First, the best thing you can do is get in touch with the Reactive
Metals folks, Bill literally wrote the book on small batch jewelry
anodizing and has come up with an etch/pre-bath for titanium and
Reactive Metals Studio, Inc
928-634-3434, 800-876-3434, 928-634-6734fx
That being said, I find I do not need a prebath with CP1 titanium,
niobium or tantalum (I don't see many jewelers using tantalum - too
expensive compared to other reactive metals, but oh so soft and fun
to work). I know that Bill recommends a procedure in his literature,
I have never used it.
Regarding voltages, I rarely have a need to exceed 70 volts or so,
and when have tried on small objects, I run into problems with spot
"burning". I generally set the maximum voltage and then control the
play of color with time, nearness to the electrode, submersion depth
and so forth. The bubbling and sparking may well be that you are
going to the maximum voltage too fast. One trick I sometimes use is
to put a resistor in line with the electrode. It does not stop the
max voltage, just delays it, allows for a slower development of the
I have found little difference in electrolytes, I generally use
trisodium phosphate (TSP).
I have had a problem with the contact point also. I can generally
get proper color by moving the contact point and re anodizing, but I
use lower voltages and when I have had a problem, I try to contact
in a less noticeable place or with the edge of the article.
I never worry about like size of cathode and anode - I use a
stainless steel beaker to hold the bath.
Good luck, and do call Bill at Reactive.
Marlin in Denver