Amperage requirements and solution concentration for anodizing titanium
Q. I am trying to anodize a large piece of 6/4 titanium, 105" x 16" x 3/4". I am looking for information on the amperage requirements and what difference I can expect from different solutions. Also, does alloying of the titanium make any difference. I would be grateful for any help.
- Las Vegas, Nevada
A. I have experience with anodizing small parts in titanium (commercially pure grade 1 and Ti 6Al 4V) and niobium, but nothing as large as your part. The current densities that I use vary from about 5 amps per square inch to less than an amp per square inch. I suggest that you start out on the lower range to avoid accidentally etching the piece. I use a solution of 3-5% by weight trisodium phosphate [linked by editor to product info at Amazon] in water. Keep the solution below 80 degrees fahrenheit. I get more vivid colors on the 6-4 than the cp titanium, probably because it seems to take a higher finish easier. If you do not already have a suitable tank, you might try anodizing the piece with a brush saturated with the solution connected to the positive lead and the piece grounded to complete the circuit. You could use a painter's brush with the metal ferrule wired to the lead and then insulate the handle for safety. Artists use this technique to paint on sheets of Titanium.Howard Bailey
custom body jewelry - Flagstaff, Arizona
May 28, 2012
Hi, Howard. Thanks for the clear answer.
Readers: We have many threads on anodizing of titanium; please use the Google Custom Search box near the top of the page to search the site for "Anodizing Titanium". Good luck.
Ted Mooney, P.E.
Pine Beach, New Jersey
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