Copy CAd/Zinc Parts plated grey???

[amobine]

When I first tried my kit, with a very small P/S the parts came out very shiny, and perfect. I now purchased a Caswell 3 Amp P/S, and when I finish the 20-30 min plating, the parts come out a very dull GREY color, and they require ALOT of polishing to get a polished zinc color.

What am I doing wrong? the bath is at approx. 120-130 degree F., I am using a 1.5 gallon pail system, and I use enough of the brightner.

Am I leaving the parts in too long?? I have the P/S cranked up to 3 amps, and it shows about .8 volt

[seanc]

Originally Posted by amobine

I have the P/S cranked up to 3 amps, and it shows about .8 volt

You've left out the most important fact: how big are your parts? W/out that number, we can't give you an answer. My guess is you're burning the plate.

You need to set the amps to whatever is appropriate for the size of the parts. 3 amps is enough for 25-30 sq-inches. Are your parts that big?

Sean

[amobine]

On average It is approx. 12 sq. inches or less.
or it may be about 2-3 bolts with washers and nuts, bolts being about 5" long, 1/2" dia.

Should I lower the amps?? Also for how long?

[seanc]

Originally Posted by amobine

On average It is approx. 12 sq. inches or less.

12" requires only 1.2 - 1.7 amps, depending on your electrolyte. At 3 amps, this part would burn badly.

or it may be about 2-3 bolts with washers and nuts, bolts being about 5" long, 1/2" dia.

Well, it can't be "about x number of parts". You have to be fairly close in total sq-inches.

A rough estimate shows a 5" x 1/2" bolt by itself is approx. 12 sq-inches. 3 of these at once would need 3.6 - 5 amps. In this case, you don't have enough current! Adding 3 nuts and washers at the same time only makes it worse.

Should I lower the amps??

Set the amps to whatever the parts require. Determine the total square inches of the parts, multiply by .14 (or .1 depending on which electrolyte), and set the current to that value.

Also for how long?

How long depends on how thick a plate you want. With the new formula at .14 amps/sq-inch, 20 minutes gives .001" thick plate.

Sean

[amobine]

I reduced the current to about .8 amps, for a approx 8 sq inch job, and left it in the bath at approx. 130 degrees F. for about 10-12 minutes, when I removed it, it was all dull grey.

After ALOT of work, they did polish up OK, but why is it not plating shiny? The parts have been cleaned, buffed and shiny before the anti-greaser bath, and I have added the brightner??

[seanc]

Do you know which formula electrolyte you're using? old or new?

In either case, your temperature is too high. Why did you choose 130º? The old formula needs 60-90º. The new formula needs 110º optimum.

As for amps, the old formula works at .075 - .100 amps/sq-inch. The new formula works at .140 amps/sq-inch.

So if you're working with the old formula, your temp is way too high. For 8" you'd want .6 - .8 amp at 70-80º

If you're working with the new formula, your temp is still too high, and your amps are too low. For 8" you'd want 1.12 amp at 110º

What current & temp. do the instructions call for?

[amobine]

I just purchased the 1.5 CopyCad kit from Caswell, so I assume that this is the "new" formula?
So for 8", I should use 1.2amp at 110 degrees

How long should I keep it in for?

Thanks

[seanc]

Originally Posted by amobine

I just purchased the 1.5 CopyCad kit from Caswell, so I assume that this is the "new" formula?

If it's a recent purchase, then it should be the new formula, but you've said some things that made it unclear.

You should have got a Plating Manual w/the kit. The manual states the time, temperature & current density needed, but you haven't used those parameters.

"The system operates at 110 deg F, and 0.14 amps per square inch of part surface area. A 20 minute plating time is sufficient for most applications, including chromating."

You first mentioned using "a very small P/S" w/good results. The new kit does not include a power supply. The old kit did. Did this first "very small P/S" come w/the kit?

So, if you have the new formula, 8" parts needs .12 amp, at 110º.

Time is your choice. It only affects the thickness of the plate, not the quality. The new formula plates .001" thick in 20 minutes. If you only want .0005", then 10 minutes. If you want .002", then 40 minutes, etc.

For nuts, bolts and other threaded fasteners, I would not go more than 20 minutes (.001")

Sean

[amobine]

I used a small 12 volt p/supply that was 600 milliamps, that came off a cordless phone chgarger. It worked perfect for 15 minutes, until it fried.

I will try the mew parameters and see how it works. Thank you

[amobine]

I tried it several times, even with a piece of metal exactly 8" sqaure, at 110 degrees F. , at 1.12 amps, for 18 minutes, and it was totally dull grey. It took me quite some time to buff the grey to a shine.

What may be happening? Also when you have a piece of metal, flat, and it is 2" x 2" , is this 4 square inches or 8 sq. inches. Do you count surface, which would be 4 sq inches per side??