clearance between parts and cathode

[elton10]

I've seen a figure somewhere calling for 3" clearance between the part and the cathodes and sides of the tank. Is there a similar clearance needed between each part? What would be the max capacity(in sq. in) of the LCD kit tanks?

thanks in advance
Elton

[Fibergeek]

That's 3" clearance between the part(s) and any cathode surface.

The parts (if you are doing more than 1 at a time) can be closer to each other, but should not touch. Since the shape of the parts can't be defined, a spec for max part capacity in the tank can't be defined either. In practice, the total surface area of the part(s) should be less than the total surface area of the cathode(s), and still conform to the 3" rule.

[elton10]

Fiber

Thanks for that info. So I gather capacity is more a function of cathode area than electrolyte amount? That is of course taking in to account the 3" clearance..

How are most folks dealing with the anode shadow on dyed parts?

[elton10]

what is the total surface area of the cathodes in the LCD kit?

[elton10]

I looked at the contents list of the kit and I think I may have answered my own question re: cathode area... Are the '8"x8" GP plates' the cathodes?

[M_D]

Originally Posted by elton10

I looked at the contents list of the kit and I think I may have answered my own question re: cathode area... Are the '8"x8" GP plates' the cathodes?

Yes. You could always add cathode are, but one other thing that can limit the capacity is this: you can only put so many amps into a given sized tank in a given period before the current raises the temperature too high for good and predictable results. If you anodize a part with .5 square feet for example, and find x amount of minutes at 2.25 absolute amps (4.5 amps per square foot) gives you the results you desire, and then try a load of 3 square feet with 13.5 amps, the results probably will not be as good. That has been my experience anyhow.

If you stabilize the electrolyte temperature with some sort of cooler, that is another matter. I have seen there are additives that can help minimize or extend the practical temperature limits, but don't have any experience with that yet.

[elton10]

MD
Thanks


The temp limits are 65 -75 degrees F?
I guess what i will do is work up the size of batches until I reach the point where the temp gets beyond.. I did notice that commercial Type II anodize set-ups do have some cooling apparatus with them..

thanks again for the info

[elton10]

Just exactly what are the 8"x8" GP plates.. what is GP..I thought anodizing used lead or aluminum cathodes?

[GramSlam]

GP Plates are lead cathode plates.