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Submerged hook for anode sheets ?

January 24, 2009

I am trying to use 3mm copper anodes sheets for a tiny acid copper plating bath. Due to the thinness of the anode there is no place to drill and tap in a conventional titanium anode hook. Instead, I've decided to use the hooks upside down. That is, drill and tap a copper bus bar and screw in an upside down titanium hook. The bottom of the hook will be immersed in the bath with a copper anode sheet hanging via a small hole. My question is how well will this perform in terms of electrical connectivity ?
Must I always bolt to anodes ?

I did some measurements of titanium hooks and noticed large voltage drops occurring at the copper/titanium interface, sometimes a 1V drop. Worst, is that this resistance can vary widely. For paralleled anode this may cause poor current balancing. This is half expected since titanium has 24x resistance of copper, and titaniums also forms an oxide layer in air. I'm curious how other people handle these issues or is it normally insignificant ?

Adam Seychell
product designer - Melbourne, Australia

Titanium is a very poor conductor of electricity. I would use brass wire as hooks. Mask if you absolutely need to.

James Watts
- Navarre, Florida
January 27, 2009