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Old 05-09-2006, 09:04 PM
seanc seanc is offline
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Default Re: Copy Cad / Zinc Trouble

Rab:

regarding "burnt" plate, give us more to go on. How big is your plate? and how many amps was going through it? Here's a link to a truly burnt plate compared to good plate:

Burnt plate

And your power supply, does it have meters for current & voltage? And the voltmeter is going up to 50v? Then you don't have a good connection. The voltage should be quite low, @ .5 - 2 v, depending on the size of the part.

If you never get any bubbles, something's certainly wrong. If it not fizzing furiously, you can't be burning it. Even small parts will "fizz" a little. Here's some videos of a part I plated. It's @ 45 sq-in surface area. The fizzing is quite evident:

Part fizzing & agitation

Since you're not getting any bubbling, I have to ask, do you have the power supply connected correctly? Positive to anodes, negative to the part?

Regarding corrosion, if the power supply was backwards (or had no connection at all), the part never plated, so it rusted. If power was correct, did you seal the part after plating, either w/WD-40 or chromate? And was it rinsed thoroughly?

As for "decorativeness", are you using the zinc brightener? Un-brightened parts will never be "decorative", they will always be dull grey. Here's a comparison of un-brightened vs brightened parts:

Bright vs non-bright plate

I have to disagree w/Ken on the temperature. The electrolyte calls for a range of 60-90º F. I get my best results at the lower end, 65-70º.

Ken, I'm curious, why do you recommend 120º? When I first had difficulties (which turned out to be insufficient current density), Caswell had me try 110º, and it was a disaster.

Sean
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