I've been spending a lot of time prepping a mahogany porch for re-finishing. Part of what I need to take care of is the eight thousand nail stains. Every single nail has a black stain in the wood around it. I have used Restore A Deck. I have also tried oxalic acid according to the directions, twice, and am not much further along than where I started. The directions state to mix the canister (12 oz) per one gallon of hot water. Apply every ten minutes, then triple rinse. While everything is still wet, I feel like the stains are gone. But when things dry out again, there are the black stains. A few of them now have changed from a black stain to more of a yellow stain. ??
So my question is, do I just keep applying again and again? Do I mix a stronger solution? I really don't know, but it sort of feels like with all the rinsing you have to do after applying the acid, you sort of recreate the stains with all the water that is applied. Is that possible?
Any suggestions on where to go from here are greatly appreciated. Also, the only acid I can find is the 12 oz containers at $8.00 a pop. What sort of places would carry this in larger containers? I've gone through quite a few of the 12oz ones and am hoping I don't have to spend that kind of cash again.