Syndicofberyl t1_ixawlz0 wrote on November 22, 2022 at 1:54 AM

Wire brush on an angle grinder. Wear a respirator and safety glasses

repstein26 OP t1_ixaz1cp wrote on November 22, 2022 at 2:12 AM

I was planning on getting an angle grinder tomorrow!

fangelo2 t1_ixb5wnf wrote on November 22, 2022 at 3:05 AM

An angle grinder is going to create a tremendous amount of dust that you definitely don’t want in your house or lungs. Grinding concrete will produce dust that can cause silicosis . If there is any black mold there, you don’t want that spread through the house. Is the paint lead based? Probably not, but it’s not a bad idea to get it tested. I would just scrape it as you are doing and spray it with a cleaner, and wipe it down. If you are going to paint it with DriLock, you don’t have to get every little piece off, just the loose stuff

phrobot t1_ixbf5yc wrote on November 22, 2022 at 4:24 AM

If you keep it wet, you won’t get much dust. But wear a respirator just in case. Then use oil based primer to cover any stains - I like Zinsser 123. Oil primer is super stinky, so again, protect your lungs, but it will cover and stick better than water based.

crankshaft123 t1_ixbfvoo wrote on November 22, 2022 at 4:30 AM

Zinnser 123 (the original formula) is white pigmented shellac. It is not oil based. That said, it's my go-to primer in most situations.

I'm not sure if it's appropriate for OP's block wall. He should probably consult the manufacturer before using it. Or at least read the label on the can.

phrobot t1_ixbfukl wrote on November 22, 2022 at 4:30 AM

On second thought, you could also just texture over the whole wall. Maybe mix water primer thick with drywall mud, and roll it on. You probably want to remove the electric box first. Depends on how thick the existing gunk is, but just covering might be way easier.