Quick Answer

Yes, diamond grinding strips dried latex paint from a slab - but use PCD tooling first, not regular metal-bond diamonds. Latex paint is elastic and loads onto plain diamond segments, glazing them in minutes. A PCD coating-removal trapezoid disc scrapes the film off in wide shavings; follow with a 30/40 diamond pass to clean the pores, then a 60/80 to profile for the next coating. For small areas, a PCD cup wheel on an angle grinder is the hand-held equivalent.

Test the Paint First

Before you commit to grinding, find out what you are actually removing. Latex is soft; epoxy and polyurethane are hard; old tar mastics are something else entirely.

• Scrape test - putty knife. If it curls off in strips, it is latex.
• Acetone test - rub with a rag. Latex does not dissolve; epoxy softens slightly.
• Heat gun test - latex bubbles and smokes; epoxy chars.
• Adhesion test - cross-hatch with a knife. If squares lift, the film is already failing and PCD will fly through it.

Tooling Sequence

Strip, clean, profile - three stages, three toolings.

For hand work on a 125 mm angle grinder, use a 6-PCD cup wheel to strip edges, around columns, and in corners where the walk-behind cannot reach.

Watch Out for These Traps

• Painted over old epoxy - PCD strips the latex but hits hard epoxy underneath; switch to a PCD-plus-diamond hybrid disc.
• Thick build-up (3+ coats) - PCD can dig in and grab. Lift the machine weight slightly and make shorter passes.
• Paint on a sealed slab - the sealer comes up with the paint; that is fine, but plan a second diamond pass afterward.
• Lead paint pre-1978 - do not dry grind without HEPA and certified lead-abatement procedure. Wet grind and bag slurry.
• Tooling glazing - if PCD stops shaving, dress it on an old concrete curb for 30 seconds to expose fresh cutters.

After Stripping - What Next

The slab is now bare, open concrete. You have a window of 24-48 h before it re-carbonates. Vacuum twice, tack rag, and either apply the new coating (epoxy, stain, or polish) or do a light 60/80 to even the profile. Do not leave a stripped slab open for a week - oil, tire marks and foot traffic recontaminate the pores.

For a polished-concrete final, continue the sequence with resin pads such as the diamond resin polishing pads after densifier. For an epoxy coating, stop at 60/80 and coat within 24 h.

Frequently Asked Questions

Q: Can I use a normal diamond cup wheel to strip latex?

It will work for 50 sqm, then glaze. Latex is polymer - it melts onto the diamond segment and stops cutting. PCD is designed for polymer film. Use PCD.

Q: How deep do I grind to get all paint out?

0.1-0.2 mm. Latex sits on the surface, not in the slab. If you are past 0.3 mm and still see color, the slab was painted by roller at saturation - switch to a 30 grit and make one more pass.

Q: Can I use a chemical stripper instead?

Yes for small spots, but on a 100 sqm garage the sludge and wash-down water is more work than PCD grinding. Grinding is faster and cleaner.

Q: Will PCD scratch my slab?

PCD leaves a coarse CSP 4-5 scratch pattern. Always follow with 30/40 and 60/80 diamond passes to bring the profile back to coating-ready.

Conclusion

Stripping latex paint by grinding is a PCD job, not a diamond job. Spec PCD tooling for the first pass, diamond for the cleanup, and recoat within 48 h. JOY TECH stocks PCD trapezoid discs for every common grinder brand and PCD cup wheels for angle-grinder edge work.