Removing rust inhibitors

[Ldsteiner]

I have a 4'x8'x.25" piece of steel that a friend got from the scrap yard to use as a welding table. The problem is that it is coated with something that prevents it from passing a current. We've tried paint removers, mineral spirits, rust removers and at least 10 different solvents and nothing touches that coating. Even the grinding wheel barely scratches it. If you work an area long enough with the grinder it seems like it melts the coating a little - like wax? I'm thought it might be a rust inhibitor or asphalt, but nothing I've tried removes it. I'd be dead before I could grind all that off! Any suggestions?

 

[CGT80]

Have you tried a heat gun and scraper?

Sandblasting might work, if it isn't too gummy, but the cost of blasting could be so much that it is better to just buy new steel.

 

[rlitman]

Is it clear? It sounds a lot tougher than cosmoline. Have you tried a solvent on it like gasoline?

 

[countryroad82]

Powdercoat?

 

[Bondo]

Ayuh,.... Get a bigger grinder with a courser wheel, 'n be more aggressive,...

 

[matt_i]

Could be an epoxy coating, they seem pretty gummy when one tries to grind it with a flap wheel. That said, once cured no solvent that I know of will remove it. I think I'd scrap it back out and put the coin towards a fresh piece.

 

[Warrenator]

Try paint stripper. Try a few different ones. Try burning it off with a blowtorch.

 

[Ldsteiner]

It's not powder coat and it's not clear. It's black. A 60 grit flap wheel works better than the grinding wheel, but either only gives you a 1/4 inch of metal with much effort. Looks like thin asphalt so epoxy might be it. Can't scrap it out. Shop mate is brought it in and is so careful with his money that he gets nasty if I say I'll pony up for a new one. Ventilation is still not the best in the workshop so I'm leery of burning an unknown substance off - though the oxy-acetylene torch is my favorite toy. I did try several paint strippers none worked. We even tried leaving solvents on overnight. Current solution is scrap steel on top of the steel plate table so I can get a current to weld. I'll try to burn it off when either the weather gets good enough to open the garage door or the fume hood gets finished over the table. Thanks.

 

[roc_on_the_rocks]

POR-15 maybe?

 

[short4stuff]

Yep gasoline and a match