CGW Abrasives 42345 Flap Disc, 4-1/2″ x 7/8″ 80 Grit Zirconia (10-Pack)

Intro
Most “bad weld finish” problems start before the weld and get worse after it—wrong grit, wrong disc type, or running a disc past its useful life. The CGW Abrasives 42345 is a Type 27 zirconia flap disc in a 4-1/2″ x 7/8″ format, sold as a 10-pack. It’s a practical restock item for weld blending and general cleanup on carbon steel (application-dependent; verify for your material).

This post focuses on what’s verified from ArcWeld.store and basic selection logic welders actually use.

Key Takeaways

• Size is 4-1/2″ diameter with a 7/8″ arbor (confirmed in product title).
• 80 grit is a common “middle” grit for blending and cleanup after initial knockdown.
• Zirconia is typically chosen for aggressive grinding on steels (material suitability depends on your job; verify).
• A 10-pack reduces downtime from running out mid-job.

Performance & Use
An 80-grit flap disc is often the “second step” after heavy removal—cleaning up weld toes, blending tacks, smoothing transitions, and prepping for paint. Type 27 (depressed center) is commonly used on angle grinders for better access and control on edges and fillets.

H3: What to compare before you buy

• Disc diameter: 4-1/2″ (fits common small angle grinders).
• Arbor size: 7/8″ (confirm your grinder’s arbor and flange setup).
• Disc type: Type 27 (verify if you prefer Type 29 for more aggressive angle work).
• Grit: 80 grit (if you need faster knockdown, you may step down in grit; if you need finer finish, step up).
• Max RPM rating: Unknown (Verify) from ArcWeld.store page—confirm the disc’s rated speed matches your grinder.

Durability & Build
Flap disc life is driven by pressure, angle, and heat. Zirconia discs are generally selected for durability on steel, but the exact backing, flap density, and max RPM are not shown on the ArcWeld.store page content captured here.

If you’re burning discs fast, check technique first: too steep an angle and too much pressure generate heat and strip abrasive faster.

Power / Specs

• Brand: CGW Abrasives (confirmed)
• Model/SKU on ArcWeld.store: 42345 – 10 PACK (confirmed)
• Disc type: Flap disc (confirmed)
• Diameter: 4-1/2″ (114.3 mm) (confirmed)
• Arbor: 7/8″ (22.2 mm) (confirmed)
• Grit: 80 (confirmed)
• Abrasive: Zirconia (confirmed)
• Max RPM: Unknown (Verify)
• Recommended base materials: Unknown (Verify) (commonly steel; verify for stainless/aluminum use)

Who It’s For

• Fabrication shops that do daily weld blending and want a predictable restock item.
• Field welders who need a 10-pack to avoid running short on cleanup discs.
• Anyone standardizing on 4-1/2″ grinders and 7/8″ arbor consumables.

Quick FAQ

Q: Is 80 grit good for removing big welds?
A: It can, but it’s usually slower than a coarser grit for heavy removal. Many shops use a coarser disc first, then 80 grit to blend.

Q: Will this fit my angle grinder?
A: It should fit common 4-1/2″ grinders with a 7/8″ arbor, but confirm your grinder’s arbor/flange setup and guard clearance.

Q: What’s the biggest safety check?
A: Confirm the disc’s max RPM rating matches your grinder and use the correct guard.

Safety Notes

• Use the grinder guard and eye/face protection. Flap discs can shed debris and throw sparks.
• Don’t exceed the disc’s rated RPM (max RPM: Unknown (Verify) — check the disc label/spec sheet).
• Let the disc do the work. Excess pressure overheats the disc and the workpiece.

“Always follow the manufacturer’s instructions and your shop’s safety procedures. If you’re unsure about fitment or ratings, verify before you buy or install.”

Where to Buy