I originally perfected Multi-Etch™ for titanium production. It’s a nonacid (pH 6.8) alternative to hydrofluoric acid. I’ve also tested it on other metals with great results.

On titanium and niobium, I use Multi-Etch™ to remove anodizing mistakes and to clean off contamination—iron from rolling mills, heat oxides, etc. Multi-Etch™ will maintain the finish on titanium and niobium as long as the metal is not etched too long. Here’s 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.

Anodized titanium unetched (top), and treated with Multi-Etch (bottom)

Anodized titanium unetched (top), and treated with Multi-Etch™ (bottom)

For a production run of two dozen pairs of titanium earrings, I use one cup of Multi-Etch™ in a two-cup Pyrex container, heated to about 150° F. You can use a thermometer or look for the built in Multi-Etch™ bubbles which tell you when it’s ready to use (visual check.) These tiny bubbles appear when the Multi-Etch™ is brought up to the correct temperature. I dangle a pair of earrings from a niobium wire into the Multi-Etch™ for 10 seconds and then rinse in distilled water. If I did three production runs a week, I would change the Pyrex cup about every three months. If you wait too long, the cup can shatter and make a mess.