Multi-Etch® is a low-acid (pH 6.8) alternative to hydrofluoric acid and can be used on the following metals:
Click here for chart of Etch Times and Effects (PDF) for all metals tested with Multi-Etch®.
More information on select metals is below. For metals not included here, ask us or send a sample and we’ll test it for you.
On titanium and niobium, I use Multi-Etch to remove anodizing mistakes and to clean off contamination—iron from rolling mills, minor heat oxides, etc. Multi-Etch will maintain the finish/texture on titanium and niobium as long as the metal is not etched too long. Above is a single piece of titanium that I left “as is” on the top, cleaned with Multi-Etch on the bottom, and then anodized. It looks like I anodized them separately but I did it all at once.
Copper and brass etch more quickly than titanium. You can use Multi-Etch to remove light firescale from silver but not from gold. You can clean iron contamination from platinum without removing any platinum ions. I’ve done limited testing with Multi-Etch on platinum for etch effects—that is, removal of platinum ions—and there doesn’t seem to be any effect. I have not tested it with rhodium plating but I assume there would be no effect on that either. Although Multi-Etch will etch glass, it does so too slowly to be practical for decorative etching.
I have used Multi-Etch to remove broken steel drill bits trapped in titanium and gold.
Multi-Etch will enhance the patterns in mokumé and the crystals in meteorites by etching the different metals at different rates, thus slightly raising one over another.
Here is some meteorite showing before and after treatment with Multi-Etch:
Although my experience is with jewelry, there are many other industries where Muti-Etch is used, such as the dental and medical industries which use a lot of titanium.