What helps paint stick to old floor that was tiled?

I've removed the old tiles from my basement floors and it has the old blk looking glue still on the floor. What will help new paint stick to it?What helps paint stick to old floor that was tiled?
ask at depot but ive always sanded with rough sand paper and a pole sander or a belt sander then use an acid wash from the depot or the paint store called muriatic acid make a solution then wash down the floor dry and then mop rinse now its rough enough to paint i use basement floor or garage epoxy from the depot it 50 dollars for enough to cover a 20 foot sqaure check that at the depot or paint store or buy a gallon of industrial enamal from the paint store from ici dulux glidden its anywhere from 27 to 50 dollars hardens to a tough finish its brite they will try to sell you a eurathane coating for porches and floors but the oil based industrial or the epoxy is best and heres a clue do the floor wait a week then do it again stonger finish and now its cool for a long timeWhat helps paint stick to old floor that was tiled?
If its a basement floor, I assume it to be concrete.





You really have to do a good job of removing the old adhesive or thinset. Usually this requires a lot of scraping.Then if you are using concrete paint, use a good concrete primer first. If you will be using a concrete stain, then a primer will not be necessary.
I am a painting contractor and orlando57 gave the correct answer, you have to etch it with the acid first or you will have very poor bonding, and you can get concrete paint that is not epoxy,but don't bother ,get the epoxy ,it will serve you better in the long run.

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