Metal finishing Q&As since 1989

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ACIDIC PRETREATMENT OF TITANIUM

I am a metal sculptor I like to incorporate anodized titanium in work for color accents. I have pretreated the Ti with a commercially available non acidic material from Reactive Metals. The results are good but are muted. I know there is an acidic pretreatment that has been traditionally used. Anyone have knowledge of this. I know the inherent dangers but have all the safety precautions. thanks

Bob Bass
artist - Monmouth, Oregon
February 11, 2010

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Titanium develops an oxide scale rapidly in air. You could either: 1) mechanically abrade it with wet/dry paper right before anodizing or 2) use a nitric/HF mixture to descale it. The latter is a pretty scary brew that will burn holes in you, but it's what I used when I did some hobby titanium finishing. Good ventilation is essential.

Dave Wichern
Consultant - The Bronx, New York
February 18, 2010

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Go to a truck stop and get a jug of brightener for aluminum or SS semi trailers. Look for one that contains hydrofluoric acid, or ammonium bifluoride or fluoboric acid.
It is still nasty stuff, but reasonably safe IF you follow the instructions.

James Watts
- Navarre, Florida
February 18, 2010