OK, I've searched the forum for quite a while for info on etching weld cross sections, remembering seeing somewhere what solutions to use...but just can't find the posts. Searched "etching", "penetration", "weld penetration", and some more.
I cut and polished some sections of welds on 1/8" and 3/16" (T's, laps and butts) and want to etch them to check for penetration.
First, there are no chem supply houses within 75 miles, so nitric acid is out. Pharmacies don't have it.
Second, I tried muriatic (HCl) acid with poor results. I used dilute (10%) and full strength pool stuff (35%), both on cold steel and heated steel. I let the acid work for about 10 minutes and saw no action...no difference in the base metal and weldment.
Third, I found some circuit board echtant at Radio Shack, but the stuff was about $10 for a small bottle and passed on that, not being sure if it would work ($$).
Vinegar is only 5% acetic acid, so I wouldn't think it would be strong enough to show contrast.
Any suggestions on what to use? Do LWS's normally carry something like that?