Weld Support Parts Blog

Tag: MIG

ER309L MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER309L MIG / GMAW filler metal is commonly used as a starting point for dissimilar-metal welding, especially when joining stainless steel to carbon steel. The value of the wire depends on the actual base metals, joint design, service conditions, and the approved welding procedure. Do not treat the filler designation alone as procedure approval. Verify the WPS, code requirements, and manufacturer data sheet before welding.
Key Takeaways
- ER309L is a common starting point for stainless-to-carbon steel MIG / GMAW work.
- Selection is not complete until you check the WPS, base metal grades, and service conditions.
- Wire diameter, shielding gas, and transfer mode are application-dependent. Unknown (Verify).
- For procedure compliance, the filler metal designation is only one part of the setup.
Where ER309L Fits in the Shop
Fabricators often use ER309L when joining stainless to mild steel or when building a transition weld between dissimilar alloys. It is also seen in repair work where the base metal mix is not the same on both sides of the joint. That does not mean it is the correct choice for every stainless job. A grade match, corrosion requirement, temperature requirement, or code rule may point elsewhere.
If you are working from a drawing or weld map, inspect the specification first. Check whether the joint is stainless-to-carbon steel, stainless-to-stainless, or a repair condition with unknown parent material. If the base metal is not confirmed, stop and verify the grade before setting up the wire.
WSP Filler Metal Finder Notes
The WSP filler metal finder should be used as a selection starting point, not a guaranteed procedure approval. It can help narrow down the wire family when you already know the joint materials and process. It does not replace a WPS, a code requirement, or the manufacturer data sheet.
Use the finder this way:
1. Identify the process as MIG / GMAW.
2. Confirm the base metal pair on both sides of the joint.
3. Check whether the service environment includes heat, corrosion exposure, or post-weld cleaning requirements.
4. Compare the recommended filler family with the approved procedure.
5. Verify diameter, shielding gas, and polarity before loading wire. Unknown (Verify).
If the recommended result differs from the WPS, follow the WPS. If there is no WPS, do not assume the finder result is enough for production welding.
Practical Check / Inspect / Verify Steps
Check: Confirm the job is actually dissimilar-metal welding. Read the print, repair note, or job traveler. Identify the stainless grade and the carbon steel grade if both are known.
Inspect: Review the joint edges for contamination, coating, rust, oil, and chloride residue. Stainless wire will not correct poor surface condition. Remove contaminants before fit-up.
Verify: Confirm the approved filler metal classification on the WPS. ER309L is listed as AWS A5.9 on the source page, but procedure approval still depends on the governing document and the application.
Check: Inspect wire diameter against the contact tip, drive rolls, feeder setup, and amperage range. Common diameters may include .023 in, .030 in, .035 in, and .045 in based on the source keywords, but actual suitability is Unknown (Verify).
Verify: Confirm shielding gas selection and flow rate with the procedure or manufacturer data sheet. Do not assume a gas mix based on wire type alone.
Troubleshooting Support
Problem: Excessive spatter.
Check voltage, wire feed speed, CTWD, and shielding gas. Inspect for poor transfer stability. Verify that the wire diameter matches the setup and that the feed path is clean.
Problem: Poor wetting on one base metal.
Check fit-up, joint prep, and torch angle. Inspect whether the joint has heavy oxidation or coating. Verify the actual base metal grade and whether ER309L is acceptable for that condition.
Problem: Crack concern after welding.
Check restraint, dilution, and cooling rate. Inspect the procedure for preheat or interpass control requirements. Verify whether the service condition requires a different filler or a different welding plan.
Problem: Uneven bead profile.
Check work angle, travel speed, and stickout. Inspect the transfer mode and arc stability. Verify that the machine settings match the approved procedure.
Product and Parts Notes
The source page identifies ER309L MIG / GMAW filler metal as the selected item page. Use that page as the reference for the specific filler metal family, then confirm the exact part details with the listing and data sheet before ordering. Any manufacturer, size, or package detail not shown on the source page is Unknown (Verify).
Do not substitute ER309L for ER312, E309L, or another stainless filler without checking the WPS and service requirement. Even within the stainless family, the wrong wire can change cracking resistance, ferrite content, or corrosion performance. Those properties are application-specific and must be verified.
Safety Notes
- Use ventilation appropriate for stainless welding fume control.
- Wear eye, hand, and skin protection suitable for arc welding.
- Confirm the work area is clear of flammables before striking an arc.
- Do not weld on unknown base metal until it is identified.
- Follow lockout, hot work, and confined space rules where applicable.
Stainless welding fumes require attention even in short production runs. Follow site ventilation rules and local safety requirements. If the joint or service condition is critical, stop and verify the procedure before continuing.
FAQ
Is ER309L MIG / GMAW filler metal only for stainless-to-carbon steel joints?
No. That is a common use, but the correct application depends on the actual base metals and the approved WPS. Verify the job before selecting the wire.
Can I use the filler metal finder as final approval?
No. The finder is a selection starting point. It does not replace code requirements, procedure approval, or the manufacturer data sheet.
What wire diameter should I buy?
Unknown (Verify). The source keywords list .023 in, .030 in, .035 in, and .045 in, but the correct diameter depends on the machine, joint, and WPS.
Do I need to match the filler to the base metal exactly?
Not always. Dissimilar-metal welding often uses a different filler family than either base metal. Verify the intended filler with the WPS and the service environment.
Sources Checked
- ER309L MIG / GMAW Filler Metal
- WSP Filler Metal Finder
Use the listed pages as selection references only. Verify the WPS, base metal grades, service conditions, and manufacturer data sheet before welding or ordering.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 20, 2026
ER308L MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER308L MIG / GMAW filler metal is a common starting point for welding 304-family stainless steel in fabrication and repair work. It is used widely, but it is not a default answer for every stainless joint. Selection still depends on the WPS, base metal grade, service conditions, joint design, corrosion exposure, and the manufacturer data sheet.
Use the information below as a support guide only. Before ordering wire or welding production parts, verify the applicable procedure, code requirements, and base material identification.
Key Takeaways
- ER308L is commonly associated with 304 and 304L stainless applications.
- It is a selection starting point, not proof of procedure approval.
- Verify base metal, service environment, and required dilution control before use.
- Check wire diameter, shielding gas, and feeder setup against the WPS and manufacturer sheet.
- If the material is not confirmed, treat the selection as Unknown (Verify).
Where ER308L Fits
ER308L MIG / GMAW filler metal is generally discussed for stainless fabrication and repair where the base material is in the 304 family. That does not mean it is suitable for every stainless-to-stainless or stainless-to-carbon transition. Mixed-material joints, elevated corrosion duty, and code work can change the filler selection.
For maintenance buyers and welders, the practical question is not “Is ER308L common?” The question is “Does the WPS and base metal confirm ER308L for this joint?” If that answer is not documented, stop and verify before welding.
Troubleshooting and Support Checks
1) Confirm the base metal
- Check: Material tags, mill certs, heat numbers, and job documents.
- Inspect: Whether the part is 304, 304L, or another stainless grade.
- Verify: If the grade is not confirmed, mark it Unknown (Verify) and do not assume ER308L is correct.
2) Check the WPS
- Check: Procedure number, filler classification, wire diameter, transfer mode, shielding gas, and pass sequence.
- Inspect: Whether the procedure allows ER308L for the joint and position.
- Verify: Code jobs may require a specific filler or additional controls beyond what is typical in general fabrication.
3) Match service conditions
- Check: Exposure to chemicals, moisture, heat, washdown, or food-contact requirements.
- Inspect: Whether the service environment changes corrosion performance expectations.
- Verify: If service conditions are unclear, treat them as Unknown (Verify) and review the design documents.
4) Inspect the wire and feed path
- Check: Spool condition, storage condition, and packaging integrity.
- Inspect: Drive rolls, liner, contact tip, and torch cable for contamination or excess drag.
- Verify: Feed issues are often mechanical, not filler-related. Correct the feeder setup before changing wire type.
5) Review shielding gas and parameters
- Check: Gas mix, flow rate, voltage, and wire feed speed against the procedure.
- Inspect: For signs of excessive spatter, lack of fusion, or poor wetting.
- Verify: Parameter windows vary by wire diameter and transfer mode. Do not guess settings.
Filler Metal Finder Notes
Use the ER308L filler metal page as a selection starting point, not as a guaranteed procedure approval. It is intended to help narrow the filler choice for stainless MIG / GMAW work, but the final decision still belongs to the WPS, code requirements, and base metal identification.
Review the provided page here: ER308L MIG / GMAW Filler Metal
Use the filler metal finder here when you need to compare support options before ordering: Filler Metal Finder
What to confirm while using the page:
- Classification: ER308L
- Process: MIG / GMAW
- Base material: 304 and 304L stainless
- Required wire diameter: Unknown (Verify)
- Shielding gas: Unknown (Verify)
- Manufacturer availability: Unknown (Verify)
If the job calls for ER308LSi, ER309L, or another stainless filler, do not substitute based only on similarity. Confirm the procedure and the engineering requirement first.
Practical Ordering Notes
Before purchase, verify the exact wire diameter needed for the gun setup and deposition rate. Common diameter options may be listed by suppliers, but the acceptable size for your job is determined by the procedure and equipment setup. If the diameter is not stated in your documents, treat it as Unknown (Verify).
Also confirm spool size, packaging, and storage plan before placing the order. Stainless wire contamination from poor handling can create problems during feeding and weld quality. Keep wire sealed until use and store it in a clean, dry area.
Safety Notes
- Use required PPE for stainless welding, including eye, face, hand, and skin protection.
- Provide ventilation or fume extraction appropriate for the work area.
- Do not weld on unidentified material without a documented verification step.
- Follow site hot-work rules, purge requirements, and contamination control procedures.
- For regulated work, follow the approved WPS and the responsible engineer’s instructions.
FAQ
Is ER308L always correct for 304 stainless?
No. It is commonly used for 304-family stainless, but you still need to verify the WPS, joint design, and service conditions. If the grade is not confirmed, the answer is Unknown (Verify).
Can ER308L be used without checking the procedure?
No. Do not treat common use as approval. The WPS or governing document controls the filler selection.
What should I check first before ordering ER308L wire?
Check the base metal grade, required wire diameter, shielding gas, and the procedure approval. If any item is missing, verify it before ordering.
Is the filler metal finder a guarantee that ER308L will work?
No. The finder is a support tool and selection starting point. It does not replace the WPS, code requirements, or manufacturer data sheet.
Sources Checked
- ER308L MIG / GMAW Filler Metal page: https://www.weldsupportparts.com/filler-metal-mig-er308l.html
- Filler Metal Finder page: https://www.weldsupportparts.com/filler-metal-finder.html
Final note: confirm the WPS, code requirements, base metal grade, service conditions, and manufacturer data sheet before welding or placing a production order.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 19, 2026
ER308LSi MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER308LSi MIG / GMAW filler metal is a common stainless wire choice when the job calls for a 308L-class deposit with improved wetting and a smoother bead profile. That higher-silicon chemistry is often used to help puddle flow and surface appearance. It does not replace procedure control. Treat the filler metal selection page as a starting point only, then verify the WPS, base metal, service environment, and required code or customer requirements before welding.
For product reference, see the ER308LSi MIG / GMAW filler metal page. For selection support, use the Weld Support Parts filler metal finder. Those pages help narrow the starting point. They do not approve a procedure by themselves.
Key Takeaways
- ER308LSi is a stainless MIG / GMAW filler metal used as a 308L-class starting point.
- Higher silicon content is commonly used to improve wetting and bead appearance.
- Verify the WPS before use. Do not assume the filler is approved because the base metal is stainless.
- Confirm base metal grade, joint design, shielding gas, and service conditions before ordering wire.
- If any technical detail is unclear, mark it as Unknown (Verify) and confirm against the manufacturer data sheet and code requirements.
When to Check the Wire Against the Job
Before you load the feeder, check whether the job actually calls for ER308LSi or another stainless filler. Stainless selection errors can show up later as fit-up issues, procedure nonconformance, or service problems.
Check: the weld symbol, WPS, job traveler, and base material identification. Inspect: the heat number, mill certs, and material tags if they are available. Verify: the base metal grade. The source page indicates 304 and 304L stainless as the base material starting point, but any final acceptance depends on the WPS and governing code.
If the stainless grade is not clearly marked, stop and confirm it. Do not assume 304, 304L, or a matching filler based on appearance alone.
Practical Setup Checks Before Welding
ER308LSi wire is used in GMAW equipment, but the correct settings depend on the machine, transfer mode, gas, wire diameter, and work thickness. Wire diameter options commonly associated with this classification may include .023 in, .030 in, .035 in, and .045 in, but the correct choice for your work is Unknown (Verify) unless confirmed by the WPS and manufacturer data sheet.
Check: the wire spool label, classification marking, and package condition. Inspect: the drive rolls, liner, torch cable, contact tip condition, and feed path cleanliness. Stainless wire is sensitive to contamination and feeding problems. Verify: that the shielding gas, polarity, and transfer mode match the procedure. Do not guess.
Before production welding, run a test bead on scrap or a coupon approved for setup. Check bead wetting, toe tie-in, arc stability, spatter level, and puddle control. If the bead profile looks wrong, stop and correct the process variables before continuing.
Troubleshooting Support
Use this quick support sequence when the weld does not look right:
1. Check feed consistency. Look for birdnesting, burnback, slip in the drive rolls, or liner drag. Stainless wire should feed smoothly. If the wire hesitates, inspect the torch path and the contact tip wear.
2. Inspect the shielding gas delivery. Confirm bottle type, flow rate setting, leaks, hose damage, and nozzle blockage. Gas problems often show up as poor bead appearance or unstable arc behavior.
3. Verify contamination control. Check base metal cleanliness, brush segregation, and solvent residue. Stainless work should not share contaminated tools with carbon steel work.
4. Verify heat input expectations. Too much or too little heat can affect wetting, penetration, and bead shape. If the WPS is not available at the work area, stop and retrieve it.
5. Confirm service requirement. If the weld is in a corrosive, elevated-temperature, or code-controlled service, verify that ER308LSi is the correct filler. If not, the correct wire may be Unknown (Verify) until engineering review is complete.
Filler Metal Finder Notes
The filler metal finder is useful when you are narrowing down stainless wire options. Use it to start the selection process, not to finalize compliance. The page should be treated as a support tool for identifying likely filler families, then the WPS and manufacturer documentation must confirm the choice.
For this classification, the listed starting reference is AWS A5.9, with ER308LSi as the classification. Keep in mind that the classification alone does not approve the wire for every 304 or 304L job. Final acceptance still depends on procedure and service demands.
If your job package lacks a clear filler callout, do not order wire based on assumptions. Verify the base material, joint condition, and required corrosion performance first.
Selection and Ordering Checks
Before purchasing filler metal, check the following:
- Classification required by the WPS
- Base metal grade and thickness
- Shielding gas requirement
- Wire diameter required by the procedure
- Heat tint or corrosion cleanup requirements after welding
- Any customer or code restriction on silicon-enhanced stainless wire
Inspect: the product label when the wire arrives. Verify: classification, lot identification, packaging integrity, and storage condition. If any of these details are missing or unclear, treat them as Unknown (Verify) and hold the product until the issue is resolved.
Safety Notes
Stainless welding still creates standard arc-welding hazards. Use proper eye, face, hand, and body protection. Keep ventilation adequate, especially on stainless work where fume control matters. Do not weld on unverified materials or in an unapproved configuration. If the wire, base metal, or procedure is not clearly identified, stop and verify before striking an arc.
Also confirm that cleaning tools are dedicated or otherwise controlled to avoid cross-contamination. Contaminated stainless welds can create quality and corrosion problems that are not visible at the torch.
FAQ
Is ER308LSi the same as ER308L?
No. ER308LSi is a separate stainless filler classification with higher silicon content. That difference is commonly used to improve wetting and bead appearance, but the correct choice still depends on the WPS and service requirements.
Can I use the filler metal finder as an approval document?
No. Use the filler metal finder as a selection starting point only. It does not replace the WPS, code requirements, or manufacturer data sheet.
What base metal is ER308LSi commonly started against?
The source page identifies 304 and 304L stainless as the starting base material reference. Final compatibility must still be verified against the actual job requirements.
What should I do if the wire diameter is not listed on the job documents?
Stop and verify. Common sizes may exist, but the correct diameter for your application is Unknown (Verify) until the WPS or engineering documents confirm it.
Sources Checked
- ER308LSi MIG / GMAW filler metal page
- Weld Support Parts filler metal finder
Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 19, 2026
ER120S-G MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER120S-G MIG / GMAW filler metal is a higher-strength low-alloy wire family used in qualified applications. Treat it as a selection starting point, not a final approval. Before ordering wire or putting arc on the joint, verify the WPS, code requirements, base metal grade, service conditions, and the manufacturer data sheet.
This article is for welders, fabricators, maintenance buyers, and welding support teams who need a practical way to screen ER120S-G for a job. The goal is to reduce selection errors before wire hits the feeder.
Key Takeaways
- ER120S-G is part of the AWS A5.28 low-alloy solid wire family for MIG / GMAW.
- The “-G” designation means the exact chemistry and properties are not fully fixed by a single specification path; you must verify the manufacturer’s classification details.
- Use it only where the WPS, code, and base metal requirements support it.
- Do not assume one ER120S-G product is interchangeable with another. Manufacturer data sheets matter.
- When in doubt, stop and verify before welding.
How to Screen an ER120S-G Job
Start with the joint requirement, not the wire spool. For high-strength low-alloy work, the job package should answer three questions: what base metal is being welded, what strength level is required, and what the service conditions are.
Check: confirm the WPS number, applicable code, and whether the procedure already names ER120S-G or an approved alternate classification. If the WPS is missing, incomplete, or out of date, do not guess.
Inspect: review the base metal identification on the traveler, mill cert, or maintenance documentation. If the base material grade is unclear, mark it Unknown (Verify) and pause selection.
Verify: confirm whether the service environment includes low temperature, impact loading, cyclic loading, or any other condition that may affect filler metal selection. Those details can change the required weld deposit properties.
Troubleshooting and Support Checks
Wire selection problems
If the part number, spool label, or purchase request says only “high-strength wire” or “ER120S-G equivalent,” do not release the order yet.
- Check: whether the exact filler metal is named in the WPS.
- Inspect: the manufacturer data sheet for classification, recommended shielding gas, and application limits.
- Verify: the wire diameter required by the procedure. If the size is not listed in your job information, mark it Unknown (Verify).
Fit-up and weld quality problems
When welds show excessive spatter, poor fusion, or irregular bead shape, the wire choice may be only part of the issue.
- Check: the feeder setup, drive rolls, liner condition, and contact tip size.
- Inspect: shielding gas flow and coverage at the arc.
- Verify: that the travel speed, voltage, and wire feed settings match the WPS. If the procedure values are unavailable, do not rely on shop memory.
Ordering and kitting problems
Maintenance buyers often have to source wire before the welder sees the job. That is where mistakes happen.
- Check: the spool size, diameter, and manufacturer line requested by the job.
- Inspect: whether the order is for a qualified replacement or a first-time approval.
- Verify: any internal substitution rules. If substitutions are not approved in writing, treat them as Unknown (Verify).
WSP Filler Metal Finder Use
The WSP filler metal finder is a starting point for selection, not a guarantee of procedure approval. Use it to narrow the candidate list, then confirm the final choice against the WPS and the manufacturer’s data sheet.
For ER120S-G, the listed family helps support search and screening, but it does not replace job-specific verification. Do not assume that a matching classification means the wire is automatically acceptable for every high-strength low-alloy application.
Use the finder when you need to compare classifications, confirm that you are in the correct MIG / GMAW family, or cross-check possible substitutes. If the job details do not clearly define the application, keep the decision open until the welding engineer, supervisor, or code authority reviews it.
ER120S-G Selection Notes
The ER120S-G filler metal page is a useful reference for this family: ER120S-G MIG / GMAW Filler Metal.
Based on the provided product information, this wire family is intended for higher-strength low-alloy steel applications. The job still needs confirmation of base metal, code, service conditions, and the exact data sheet from the manufacturer. Common search terms associated with this family include ER120S-G, ER100S-G, MIG / GMAW, and low-alloy steel, but those terms are only search aids. They are not proof of interchangeability.
If the wire diameter, shielding gas, or specific manufacturer is not documented, treat that information as Unknown (Verify). Do not fill in the blanks from another job or from a similar part number.
Practical Check List Before You Weld
- Check the WPS number and revision.
- Inspect the base metal identification.
- Verify the service condition and required mechanical properties.
- Confirm that ER120S-G is approved or allowed by the procedure.
- Review the manufacturer data sheet for the exact product being used.
- Check spool size, wire diameter, and shielding gas requirements.
- Inspect the feeder, liner, tip, and drive rolls before starting.
- Verify that the welder understands any preheat, interpass, or heat input limits.
Safety Notes
Use normal welding controls for arc flash, fume exposure, hot work, and fire risk. Higher-strength wire does not reduce the need for basic safety discipline. Follow the jobsite hot work rules, ventilation requirements, and personal protective equipment requirements. If the procedure, material identification, or service condition is unclear, stop and verify before welding.
FAQ
Is ER120S-G a procedure approval by itself?
No. ER120S-G is a filler metal classification. Approval depends on the WPS, code, base metal, and service requirements.
Can I substitute another wire family because it is “close enough”?
Not without written approval. Treat substitution as Unknown (Verify) until the WPS or welding authority confirms it.
Does the WSP filler metal finder replace the manufacturer data sheet?
No. The finder is a starting point for selection. Final use must be checked against the actual product data and the job requirements.
What should I do if the base metal grade is not listed?
Stop and verify the material grade before selecting wire. Do not assume the material from appearance or from a previous job.
Sources Checked
- WSP filler metal finder: https://www.weldsupportparts.com/filler-metal-finder.html
- ER120S-G MIG / GMAW Filler Metal page: https://www.weldsupportparts.com/filler-metal-mig-er120s-g.html
This draft uses only the provided Weld Support Parts filler metal pages and keeps selection guidance at a verification-first level.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 17, 2026
ER100S-G MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER100S-G is a MIG/GMAW filler metal family used on high-strength low-alloy steel applications where the weld procedure calls for higher-strength filler selection. Treat the classification as a starting point, not a final approval. Before ordering wire or striking an arc, verify the WPS, the code requirement, the base metal grade, the service conditions, and the manufacturer data sheet. If any of those inputs are unclear, the correct answer is not to assume. The correct answer is to verify.

Key Takeaways
- ER100S-G is an AWS A5.28 classification for MIG/GMAW wire used in higher-strength low-alloy applications.
- The “G” classification means general composition is not fully fixed by the classification alone. Verify the manufacturer data sheet before use.
- Do not select this wire only by strength number. Match the weld metal to the WPS, base metal, and service conditions.
- Use the filler metal finder page as a selection starting point, not as proof that a wire is procedure-approved for your job.
- Wire diameter, shielding gas, and parameter set are Unknown (Verify) unless confirmed on the datasheet and WPS.
What ER100S-G Means in Practice

For maintenance buyers and fabricators, ER100S-G usually comes up when the application needs a higher-strength weld metal than common mild steel wire choices. It is associated with HSLA steel work, but that does not mean it fits every HSLA job. The designation alone does not tell you the complete chemistry, toughness level, or procedure limits. Those details are controlled by the specific product datasheet and the approved welding procedure.

When reviewing a job package, start with the base metal specification and the service environment. Then check whether the WPS calls for ER100S-G or allows an equivalent filler. If the WPS is missing, stop and verify it before purchase. If the code requirement is unclear, stop and verify that too.

Filler Metal Finder Section

Weld Support Parts lists ER100S-G here as a selection aid:

ER100S-G MIG / GMAW Filler Metal

Use the filler metal finder page to compare categories and narrow down options:

WSP Filler Metal Finder

These pages help with identification and shortlisting. They do not replace the WPS, code review, or manufacturer documentation. They do not guarantee procedure approval.

Check, Inspect, Verify Before Ordering

Check: Confirm the base metal grade, joint design, process, and any code constraints. If the job uses impact toughness requirements, crack-sensitive service, or postweld heat treatment limits, verify those details first.

Inspect: Review the existing wire, spool label, and job paperwork. Look for the classification, lot identification, and any supporting documentation. If the label is incomplete, treat it as Unknown (Verify).

Verify: Confirm diameter, shielding gas, and operating range on the manufacturer data sheet. If the datasheet is not available, do not assume .035 in, .045 in, or any other size is available for the job. Verify all consumable details before issuing to production.

Troubleshooting and Support Notes

If weld quality is not meeting expectations, separate the filler-metal question from the machine-settings question.
- Check the WPS first. If the procedure does not call for ER100S-G, do not substitute without approval.
- Inspect the wire condition. Look for rust, contamination, birdnesting damage, or storage exposure.
- Verify shielding gas and flow. Gas type and flow rate are application-dependent and Unknown (Verify) unless specified by the WPS and datasheet.
- Verify drive roll and liner setup. Poor feeding can look like a metallurgy issue when it is actually a delivery issue.
- Check base-metal cleanliness. Mill scale, oil, moisture, and paint can drive porosity and lack of fusion.
If the weld is cracking, do not keep increasing heat or changing wire blindly. Verify hydrogen control, restraint, joint prep, interpass temperature, and whether the selected filler is appropriate for the actual base material and service condition.

What to Confirm With the Manufacturer Data Sheet

Before purchase, confirm the following on the datasheet or product page:
- Classification and AWS specification
- Recommended shielding gas
- Available diameters
- Typical operating position or positions, if stated
- Storage and handling requirements
- Any mechanical property or toughness data the manufacturer publishes
If any of those points are not shown on the page you are reviewing, they are Unknown (Verify). Do not fill the gap with assumptions or with a different brand’s datasheet.

Practical Buyer Guidance

For support teams, the key purchase risk is choosing a filler by classification only. Two wires with the same classification can still differ by manufacturer, intended gas, and published properties. That matters when you are supporting a WPS-driven shop or a field repair program.

When a buyer is asked to source ER100S-G, collect the following before ordering: job number, WPS number, base material, required diameter, spool size if applicable, shielding gas, and any code or customer requirement. If a field technician cannot provide those inputs, pause the order and verify the application.

Safety Notes
- Follow the site WPS and the filler metal manufacturer instructions.
- Use proper ventilation and fume control for all GMAW operations.
- Keep wire dry and clean. Do not use contaminated consumables.
- Do not weld from incomplete information on critical joints.
- If the job is safety-critical or code-controlled, verify the procedure with welding engineering or quality control before use.
FAQ

Is ER100S-G the right wire for all high-strength steel repairs?
No. It may be suitable for some high-strength low-alloy steel applications, but the correct choice depends on the WPS, base metal grade, service conditions, and code requirements.

Can I choose ER100S-G just because the strength number looks correct?
No. The classification alone is not enough. Verify the full procedure and manufacturer data sheet before using it.

What wire diameter should I order?
Unknown (Verify). Confirm the allowed diameter on the WPS and the specific product page or datasheet before ordering.

Does the filler metal finder page approve a procedure?
No. It is a selection tool. Use it to narrow choices, then verify against the WPS and supporting documentation.

Sources Checked
- ER100S-G MIG / GMAW Filler Metal: https://www.weldsupportparts.com/filler-metal-mig-er100s-g.html
- WSP Filler Metal Finder: https://www.weldsupportparts.com/filler-metal-finder.html
No additional product, ASIN, or internal-link data was provided for this draft.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 16, 2026
ER80S-Ni1 MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER80S-Ni1 is a nickel-bearing low-alloy solid wire used in MIG/GMAW applications where toughness and low-temperature performance may matter. It is also considered in some weathering steel applications when the job calls for a better color match or when the governing procedure allows this classification. That said, the wire classification alone does not approve the weld. The final decision still depends on the WPS, code requirements, base metal grade, joint design, shielding gas, and the manufacturer data sheet.

Use this page as a selection aid, not as a procedure approval. Before ordering wire, verify the job requirements and confirm the exact product listing on the Weld Support Parts filler metal page.

ER80S-Ni1 MIG / GMAW Filler Metal

Key Takeaways
- ER80S-Ni1 is a classification, not a complete welding procedure.
- It is associated with low-alloy steel service where toughness requirements may be important.
- Weathering steel color match may be a reason to review this wire, but match expectations must be verified against the job spec.
- Confirm base metal grade, service temperature, and code rule before purchase.
- Use the manufacturer data sheet and the approved WPS as the final reference.
Where This Wire Fits

For maintenance buyers and welding support teams, the practical question is not only “What is the classification?” but “What is the approved use on this job?” ER80S-Ni1 is commonly reviewed for low-alloy steel work and selected weathering steel applications. If the work involves low-temperature service, impact requirements, or matching existing weld appearance, check the project documents first. Unknown (Verify): exact mechanical property targets, shielding gas recommendation, and all-position limitations depend on the manufacturer and the WPS.

Selection Check: Verify Before You Order
1. Check the WPS. Confirm the filler classification, wire diameter, shielding gas, polarity, and technique listed for the job.
2. Inspect the base metal callout. Verify the steel grade on the drawing, MTR, or repair package. Weathering steel is not a single universal category.
3. Verify service conditions. Low-temperature exposure, impact loading, and cyclic service can change filler metal selection.
4. Review code and customer requirements. A classification that looks suitable may still be disallowed by project rules.
5. Confirm the manufacturer data sheet. Do not rely on the classification alone for final acceptance.
Troubleshooting and Support Notes

If the wire is already in house and the job is not welding as expected, work through the issue systematically.

Check
- Check the wire label against the purchase order and the WPS.
- Check the spool condition for rust, contamination, or damage.
- Check shielding gas type and flow.
- Check drive rolls, liner condition, tip size, and contact tip wear.
Inspect
- Inspect the joint for mill scale, oil, moisture, or weathering products that can affect arc stability.
- Inspect for incorrect polarity or loose connections.
- Inspect for excessive stickout or inconsistent travel speed.
- Inspect the weld surface for porosity, undercut, lack of fusion, or erratic bead profile.
Verify
- Verify the wire is the classification actually specified for the job.
- Verify that the base metal really is the grade expected by the WPS.
- Verify that preheat, interpass control, and heat input limits are being followed.
- Verify whether the job requires impact testing or other mechanical property control.
If defects persist after the basics are corrected, stop and compare the job to the approved WPS. Do not continue on a critical weld with an unverified filler choice.

Filler Metal Finder Reference

The Weld Support Parts filler metal finder is a starting point for narrowing the classification, process, and application. It should not be treated as a guaranteed procedure approval tool. Use it to help identify candidate wires, then confirm against the job documents and data sheet.

Filler Metal Finder

When searching for ER80S-Ni1, focus on the classification first, then verify wire diameter, spool size, and brand only after the technical requirement is confirmed. The keywords associated with this finder topic may include low-alloy steel, weathering steel, and low-temperature steels. Unknown (Verify): exact brand availability, diameters, and package sizes depend on the current listing.

Practical Use Notes for Shop Teams

For welders, this wire may be considered when a joint needs stronger toughness than a basic carbon steel filler provides, or when the procedure calls for a nickel-bearing low-alloy wire. For fabricators and maintenance buyers, the main risk is substitution. A similar-looking filler may not satisfy the same mechanical or code requirement.

Before you substitute anything, confirm three things: the WPS allows it, the base metal matches, and the service condition supports the choice. If any one of those is uncertain, the correct answer is Unknown (Verify).

Safety Notes
- Follow the approved WPS and site hot-work rules.
- Use proper ventilation and fume control for all GMAW operations.
- Wear correct eye, hand, and body protection.
- Handle wire and spools carefully to avoid cuts, entanglement, and contamination.
- Do not weld on unverified material or service-critical repairs without approval.
FAQ

Is ER80S-Ni1 automatically approved for weathering steel?

No. It may be reviewed for some weathering steel applications, but approval depends on the WPS, the exact base metal grade, and project requirements. Verify before use.

Can I choose ER80S-Ni1 based on the classification alone?

No. The classification is only a starting point. Confirm shielding gas, wire diameter, base metal, service temperature, and any required testing.

What should I check first if weld quality is poor?

Check the wire label, shielding gas, drive system, contact tip condition, and joint cleanliness. Then verify polarity and the WPS settings before changing the filler metal.

Does this page guarantee suitability for low-temperature service?

No. Low-temperature suitability depends on the approved procedure and the actual material requirements. Unknown (Verify): the exact toughness performance for a specific product and condition.

Sources Checked
- Weld Support Parts product page: ER80S-Ni1 MIG / GMAW Filler Metal
- Weld Support Parts filler metal finder: Filler Metal Finder
Final note: this page is a support reference only. Use the approved documentation and the manufacturer data sheet before welding or ordering.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 15, 2026
ER70S-7 MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER70S-7 MIG / GMAW filler metal is a solid wire option used on carbon steel and mild steel applications where extra deoxidizers may help with less-than-perfect surface condition. Treat it as a starting point only. Before ordering or welding, verify the WPS, code requirements, base metal grade, service conditions, and the manufacturer data sheet.

Key Takeaways
- ER70S-7 is a MIG / GMAW solid wire classification for carbon steel work.
- It is often considered when the joint condition is not ideal and extra deoxidizers may be useful.
- Do not use the classification alone as approval for a weld procedure.
- Check the WPS, base metal, shielding gas, and wire diameter before setup.
- If any technical detail is unclear, mark it as Unknown (Verify) and confirm it before release to production.
What the filler metal finder page is for

The ER70S-7 MIG / GMAW Filler Metal page is a selection starting point. It helps narrow the classification and common use case, but it does not guarantee procedure approval, code compliance, or fit for a specific job. Use it to begin the review, then verify the rest against your welding documentation and material controls.

How to verify fit before welding

Use a simple check sequence before the first arc.
- Check the WPS: Confirm the procedure lists ER70S-7 or allows an equivalent classification. If the WPS is missing, stop and obtain it.
- Inspect the base metal: Verify the base material grade, thickness, and joint design. If the grade is not confirmed, record it as Unknown (Verify).
- Verify service conditions: Confirm whether the weld is for general fabrication, repair, structural work, or another service. Service exposure may change filler metal acceptability.
- Inspect surface condition: Look for mill scale, rust, oil, moisture, paint, or shop contamination. ER70S-7 may be helpful in less-than-perfect surface condition, but it is not a substitute for cleaning.
- Verify shielding gas: Check the gas type required by the WPS and wire manufacturer data sheet. If not documented, treat it as Unknown (Verify).
- Confirm wire diameter: Common search terms include .030 in, .035 in, and .045 in, but do not assume any size is approved for your job. Verify the actual diameter allowed by procedure and feeder setup.
Troubleshooting support checks

If the weld does not run as expected, use a sequence that separates machine issues from material issues.

1) Arc instability
- Check contact tip size and condition.
- Inspect wire feed path for blockage, liner wear, or drive roll slippage.
- Verify shielding gas flow at the nozzle.
- Confirm polarity and machine settings against the WPS.
2) Excessive spatter
- Check voltage and wire feed speed.
- Inspect stickout length and gun angle.
- Verify the work surface is clean enough for the selected wire.
- Confirm the wire classification matches the application, not just the machine setting.
3) Porosity or surface contamination
- Inspect the joint for moisture, oil, rust, paint, and scale.
- Check shielding gas coverage and leaks.
- Verify the base metal condition before welding starts.
- If contamination persists, stop and clean the joint rather than increasing heat to compensate.
Selection notes for maintenance buyers and support teams

For purchasing and stock review, ER70S-7 should be treated as one option within a controlled filler metal list. Do not assume it replaces ER70S-6, and do not assume it is interchangeable without procedure review. For shop support, keep the following records aligned:
- wire classification
- wire diameter
- shielding gas requirement
- WPS number or repair instruction
- base metal grade
- heat input or preheat limits, if applicable
If any one of those points is missing, the correct status is Unknown (Verify).

Practical check before release to production
1. Verify the job traveler or WPS references ER70S-7 or an approved equivalent.
2. Inspect the wire label and lot information before loading the feeder.
3. Check that the gas bottle, regulator, and hoses match the required setup.
4. Verify the coupon or first article weld meets the project criteria.
5. Document any repairs, changes, or deviations before continuing production.
Safety notes
- Follow shop ventilation and fume control requirements.
- Keep the work area dry and free from flammables.
- Do not weld on unknown material without confirming the base metal and service condition.
- Wear the proper PPE for MIG / GMAW work, including eye, face, hand, and body protection.
- Do not rely on filler metal selection alone to solve fit-up, contamination, or machine setup problems.
FAQ

Is ER70S-7 the same as ER70S-6?

No. They are different classifications. Do not assume interchangeability. Verify the WPS and manufacturer data sheet before substitution.

Can ER70S-7 be used on dirty or scaled steel?

It is often considered when extra deoxidizers may help with less-than-perfect surface condition, but it is not a substitute for cleaning. Inspect the joint and clean it as needed before welding.

What wire diameter should I stock?

Unknown (Verify). Common search terms include .030 in, .035 in, and .045 in, but the correct size depends on the WPS, machine setup, and job requirements.

Does the filler metal page approve a weld procedure?

No. The filler metal page is a starting point for selection only. Procedure approval still depends on the WPS, base metal, service conditions, and code requirements.

Sources Checked
- ER70S-7 MIG / GMAW Filler Metal
- Filler Metal Finder
Note: No additional product, price, certification, or compatibility claims were used. Any technical point not confirmed in the provided source material should be treated as Unknown (Verify).

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 13, 2026
ER70S-6 MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER70S-6 MIG / GMAW filler metal is a common starting point for mild steel and carbon steel fabrication, repair, and general shop work. It is widely used because it supports routine production welding and maintenance work where good fit-up, practical deposition, and broad application matter. That said, the filler wire is only one part of the weld package. Final selection still depends on the WPS, base metal, service condition, joint design, shielding gas, and any code or customer requirements.

Use the WSP filler metal page and the filler metal finder as selection references, not as automatic procedure approval. The product page for ER70S-6 MIG / GMAW Filler Metal and the filler metal finder are starting points for narrowing the choice. They do not replace a qualified WPS or manufacturer data sheet.

Key Takeaways
- ER70S-6 is a general-purpose solid wire for MIG / GMAW on mild steel and carbon steel.
- Do not treat a filler metal listing as proof of WPS compliance.
- Verify base metal grade, thickness, service environment, and shielding gas before ordering wire.
- Match wire diameter to the application and the procedure. Common sizes may include .023 in, .030 in, .035 in, and .045 in, but the correct size is procedure-dependent and may be Unknown (Verify).
- For critical work, confirm code requirements and manufacturer data sheets before welding.
How to Use ER70S-6 as a Starting Point

ER70S-6 is often selected when the job calls for a dependable solid wire for shop fabrication, repair work, and general maintenance on carbon steel. It is often considered alongside ER70S-3 and ER70S-2 during selection, but the right choice depends on cleaning level, deposition needs, and the procedure in use. Do not assume a wire works because it is common. Check the actual base metal and the weld requirement first.

Check: the base material identification, thickness, and any drawing notes.
Inspect: the joint condition, contamination, rust, mill scale, primer, and moisture.
Verify: the WPS, shielding gas, polarity, and wire diameter before loading the feeder.

Troubleshooting and Support Checks

If the arc is unstable, the weld bead profile is inconsistent, or spatter is higher than expected, do not assume the wire is wrong. Start with the setup and consumable path.

Check the gun liner, contact tip, drive roll tension, and wire feed path for drag or birdnesting risk.
Inspect the shielding gas delivery, flow settings, leaks, and nozzle condition.
Verify the wire diameter matches the drive roll groove, contact tip, and procedure requirements.

If porosity appears, the first checks should be gas coverage, surface contamination, and stickout. If there is excessive spatter, review voltage, wire feed speed, inductance if available, and whether the wire is being used within the intended procedure. If fusion is poor, verify travel speed, work angle, joint prep, and heat input settings. These are support checks, not guaranteed fixes. Unknown (Verify) details should be confirmed against the WPS and the manufacturer data sheet.

Filler Metal Finder Notes

The filler metal finder is useful when the team is sorting through options for mild steel and carbon steel work. Treat it as a filtering tool. Start with the process, classification, and base metal family, then narrow by job requirement. The finder can help reduce guesswork, but it cannot approve a weld procedure.

Use these practical selection questions:
- Is the job MIG / GMAW and solid wire is allowed by the WPS?
- Is the base metal mild steel or carbon steel?
- Does the service condition require a different filler or higher control?
- What diameter is called out, or what size is permitted by the procedure?
- Is the shielding gas specified, or is it Unknown (Verify)?
If any answer is unclear, stop and verify before purchase. A common wire selection can still be wrong for the application if the service environment, code, or procedure is not matched.

Ordering and Setup Checklist

Before you order or load ER70S-6 wire, run this basic check sequence:
- Check the WPS number and revision.
- Inspect the base metal marking, mill certs, or job traveler if available.
- Verify that the shielding gas, polarity, and wire diameter are compatible with the procedure.
- Check spool size and feeder capacity for the job volume.
- Inspect storage conditions to reduce moisture and contamination risk.
If the documentation is incomplete, the technical answer is not to guess. Mark the missing data as Unknown (Verify) and confirm it through the welder, supervisor, engineer, or manufacturer data sheet.

Safety Notes

Welding safety still applies when using a standard mild-steel solid wire. Keep the work area ventilated, protect against arc radiation, and control fumes generated by base metal, coatings, and contamination. Remove flammables from the weld area and use correct PPE. Verify local procedures for hot work, cylinder handling, and shop ventilation. If the job involves coated, painted, plated, or dirty steel, the fume and cleanup risk may be higher than expected.

FAQ

Is ER70S-6 a universal choice for all MIG welding?
No. It is a common starting point for mild steel and carbon steel, but the final choice depends on the WPS, base metal, service conditions, and code requirements.

Can I use the filler metal page as proof of procedure approval?
No. The filler metal page is a selection reference only. Confirm the WPS and manufacturer data before welding.

What wire diameter should I buy?
Use the diameter listed by the procedure or job requirement. Common sizes may include .023 in, .030 in, .035 in, and .045 in, but the correct size for a given job may be Unknown (Verify) until the WPS is checked.

What should I verify before troubleshooting weld defects?
Verify gas delivery, base metal condition, contact tip condition, wire feed path, polarity, and the weld settings before assuming the filler wire is the root cause.

Sources Checked
- ER70S-6 MIG / GMAW Filler Metal product page: https://www.weldsupportparts.com/filler-metal-mig-er70s-6.html
- WSP Filler Metal Finder: https://www.weldsupportparts.com/filler-metal-finder.html
Final note: use the product page and the finder as support tools, then verify the job requirements before ordering or welding. When in doubt, stop and confirm the WPS, base metal, and manufacturer data sheet.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 12, 2026
ER70S-3 MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER70S-3 MIG / GMAW filler metal is a general-purpose solid wire used on clean carbon steel fabrication. It is typically treated as a starting point for selection, not a final approval for production welding. Before ordering wire or loading a feeder, verify the WPS, code requirements, base metal grade, joint condition, shielding gas, and the manufacturer data sheet.

Key Takeaways
- ER70S-3 is a solid MIG/GMAW wire for clean mild steel and carbon steel.
- Use it as a selection starting point, not as proof of WPS compliance.
- Lower deoxidizer content means surface condition matters more.
- Confirm wire diameter, shielding gas, and procedure limits before welding.
- If the joint has rust, mill scale, or contamination, verify whether a different wire or cleaning method is required.
What to Check Before You Order

For ER70S-3, the key question is not just whether the wire matches the material family. It is whether the job condition matches the wire’s intended use. This wire is presented on the WSP filler metal page as a general-purpose option for clean carbon steel fabrication. That means fit-up, cleaning, and procedure control matter.

Inspect: Base metal type, surface contamination, joint prep, and required weld procedure. Check whether the job uses carbon steel that is clean enough for a general-purpose solid wire. Review the applicable code or spec if the job is code-controlled.

Verify: The WPS, wire classification, shielding gas, polarity, and diameter. The source page lists ER70S-3 under AWS A5.18, but the job still needs procedure-level verification. If any detail is unclear, record it as Unknown (Verify) rather than assuming it will work.

Check: The filler metal page and the filler metal finder page together as selection tools. Use them to narrow choices, then confirm with the manufacturer data sheet and internal welding requirements before purchase.

Troubleshooting Support

If weld quality is inconsistent, do not start by changing only parameters. Start by checking the basics.

Issue: Excess spatter or unstable arc
- Check: Shielding gas setup, stickout, contact tip condition, and drive roll tension.
- Inspect: Wire feed path for drag, liner wear, and contamination.
- Verify: That the wire diameter matches the feeder setup and procedure. Unknown (Verify) if the feeder has been reconfigured since the last job.
Issue: Porosity
- Check: Base metal cleanliness, gas coverage, and leaks in hoses or fittings.
- Inspect: Rust, oil, moisture, paint, or mill scale on the joint.
- Verify: Whether the material condition is suitable for ER70S-3 or if the procedure calls for different cleaning or filler selection.
Issue: Poor wetting or inconsistent bead shape
- Check: Voltage, wire feed speed, travel speed, and torch angle.
- Inspect: Joint gap and part fit-up.
- Verify: That the welding parameters align with the approved WPS. Do not assume a setting that worked on one job is valid for another.
Filler Metal Finder Notes

The WSP filler metal finder page is useful when you need to narrow a wire choice from process and base metal information. It should be treated as a selection starting point only. It does not replace the WPS or manufacturer data sheet.

Use the finder page to confirm the wire family for MIG / GMAW applications and then compare it against the job requirements. For ER70S-3, the practical question is whether the base metal is clean enough and whether the procedure allows this general-purpose wire. If the service condition is critical, high restraint, or code governed, verify all requirements before release to production.

ER70S-3 MIG / GMAW filler metal page

WSP filler metal finder

How to Use This Wire Correctly

ER70S-3 is generally used on clean carbon steel where a solid wire is appropriate. The practical checks are simple, but they need to be done in order.
1. Check the job requirements. Confirm the WPS, material grade, and service conditions.
2. Inspect the joint. Remove oil, moisture, and loose contamination. Unknown (Verify) if surface cleanliness is acceptable without further prep.
3. Verify the machine setup. Confirm polarity, drive rolls, liner, tip size, and shielding gas.
4. Run a test weld. Evaluate bead shape, fusion, and spatter before production welding.
5. Document results. If the weld is intended for a controlled job, keep the settings and observations with the job record.
Safety Notes
- Use proper ventilation or local exhaust when welding.
- Wear the required eye, hand, and body protection for MIG welding.
- Keep shielding gas cylinders secured and fittings leak-checked.
- Do not weld without verifying the base material and procedure requirements.
- If the metal condition is unknown, stop and verify before proceeding.
FAQ

Is ER70S-3 a general-purpose MIG wire?
Yes, it is presented as a general-purpose solid MIG/GMAW wire for clean carbon steel fabrication. That does not mean it is approved for every job. Verify the WPS and base metal first.

Can I use ER70S-3 on rusty or dirty steel?
Not as a default assumption. Lower deoxidizer content means the joint condition matters more. Inspect the surface and verify whether additional cleaning or a different filler is required.

Does the WSP page replace the manufacturer data sheet?
No. Use the WSP page and the filler metal finder as selection tools only. Verify the final choice with the manufacturer data sheet and the project requirements.

What should I verify before buying wire?
Check the classification, diameter, shielding gas requirement, WPS, base material, and service conditions. If any item is unclear, mark it as Unknown (Verify).

Sources Checked
- ER70S-3 MIG / GMAW Filler Metal
- WSP Filler Metal Finder
This draft is intended for welders, fabricators, maintenance buyers, and welding support teams who need a practical starting point for filler metal selection. Final responsibility for procedure compliance remains with the user and the governing welding documentation.

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 11, 2026
ER70S-2 MIG / GMAW Filler Metal: Filler Metal Finder Notes
ER70S-2 MIG / GMAW filler metal is a solid carbon steel wire used as a forgiving starting point for mild steel and general carbon steel work. It is commonly considered when fit-up is not perfect, mill scale is present, or surface condition is less than ideal. That said, it is not a substitute for the weld procedure specification. Before ordering wire or striking an arc, verify the WPS, code requirements, base metal grade, service conditions, and the manufacturer data sheet.

Key Takeaways
- ER70S-2 is a solid wire for MIG / GMAW carbon steel applications.
- Use the filler metal page as a selection starting point only, not a procedure approval.
- Confirm base metal, joint design, shielding gas, and wire diameter with the WPS.
- When fit-up or surface condition is questionable, inspect the joint before you assume the wire will solve the problem.
- If a requirement is unclear, mark it as Unknown (Verify) and check the governing document.
What the Filler Metal Finder Page Does

The ER70S-2 MIG / GMAW filler metal page and the filler metal finder are useful starting points for narrowing a wire choice. They help you move from a general application to a candidate filler metal, but they do not replace the WPS, engineer approval, or code review.

For this wire, the known basics are limited to the following: classification ER70S-2, AWS specification AWS A5.18, process MIG / GMAW, and intended use on mild steel and carbon steel. Any other detail such as recommended gas mix, weld position limits, current range, or diameter selection must be verified from the actual manufacturer data sheet or the project WPS. If that data is not available, record it as Unknown (Verify).

Practical Selection Checks

Use these checks before you put ER70S-2 into service:
1. Check the WPS. Verify that solid wire carbon steel filler is allowed for the joint and material group.
2. Inspect the base metal. Confirm the parent metal is mild steel or carbon steel as expected.
3. Verify service conditions. If the part sees low temperature, pressure, fatigue, or code-controlled service, do not assume this wire is acceptable without review.
4. Inspect joint prep. Look for rust, oil, paint, heavy scale, moisture, and dimensional mismatch.
5. Verify shielding gas. Do not guess. The correct gas and flow settings are Unknown (Verify) unless the WPS and manufacturer sheet state them.
6. Confirm wire diameter. Common sizes may exist, but use only the diameter specified for the job. If not specified, Unknown (Verify).
Troubleshooting and Support

If weld quality is inconsistent, work through the problem in order. Do not start by changing wire type unless the procedure allows it.

1. Verify the joint condition
- Inspect for contamination on both sides of the joint.
- Verify that loose mill scale, rust, and paint are removed to the level required by the WPS.
- Check root opening, land, and fit-up consistency.
Poor joint condition often looks like a wire problem when it is actually a preparation problem.

2. Verify the machine setup
- Check wire feed consistency and drive roll condition.
- Inspect liner wear, tip wear, and contact tip size.
- Verify polarity and gas delivery against the WPS. If not stated, Unknown (Verify).
Erratic feed can cause stubbing, spatter, and poor bead appearance. Do not treat these symptoms as proof that ER70S-2 is the wrong filler.

3. Verify the weld outcome
- Inspect bead profile, tie-in, and edge wetting.
- Check for undercut, porosity, and visible lack of fusion.
- Verify that the finished weld meets the acceptance criteria for the job.
If defects repeat, stop and compare the actual setup to the WPS line by line.

How to Use This Page in Purchasing

For maintenance buyers and welding support teams, the right workflow is simple: identify the application, pull the WPS, confirm the filler classification, and then compare the wire page to the manufacturer documentation. The filler metal finder page narrows the field, but it does not authorize substitution by itself.

When a detail is missing from the job packet, do not fill the gap with assumptions. Record the missing item as Unknown (Verify) and request the source document. That includes shielding gas, wire diameter, polarity, and any approval for out-of-position or restricted-service work.

Safety Notes
- Follow the WPS and site safety rules before welding.
- Use ventilation, fume control, and appropriate PPE.
- Do not weld on unknown or unverified base metal without clearance.
- Handle wire spools carefully to avoid contamination and damage.
- If the weld is for code work, pressure work, or critical service, verify the procedure and inspection plan first.
FAQ

Is ER70S-2 the same as ER70S-6?

No. They are different classifications. If either can be used on a job, that must come from the WPS or engineering direction, not from assumption.

Can I use ER70S-2 on rusty steel?

It may be considered when fit-up or surface condition is less than ideal, but that does not mean dirty steel is acceptable. Clean the joint to the required level and verify the WPS. If the required prep is unclear, Unknown (Verify).

What shielding gas should I use?

Unknown (Verify) unless the WPS or manufacturer data sheet states it. Do not guess gas type or flow rate.

Can I select wire from the filler metal finder without a WPS?

No. Use the finder page only as a starting point. It helps identify a likely filler family, but it does not replace procedure approval or code compliance.

Sources Checked
- ER70S-2 MIG / GMAW filler metal page
- WSP filler metal finder
Reviewed details were limited to the provided WSP pages and the information supplied in the draft brief. Any unlisted technical detail remains Unknown (Verify).

Disclosure: As an Amazon Associate, Weld Support Parts may earn from qualifying purchases.
July 10, 2026