Copy Cad Help (Power Supply Problem ?)

[Rab]

I cannot seem to achive any good results with my copy cad system,I need some help regarding my power supply. I bought a little benchtop variable power supply that has adjustable current limiting and adjustable voltage control. It is pretty much identical looking to the 3 amp rectifier that Caswell sell, it is rated at 0-50 volt, 0-3 amp. I had thought that I could simply dial in the amps and volts that I needed for my job, this was not the case. I could not get the voltage to the desired level at around 2v without raising the current up to around 2.5 amps, which was much to high for my half a dozen or so nuts and bolts. I tried to fit a bulb in series with the anode and hey presto I was able to get the desired .25 amps and 3v showing on the digital read-out on the power supply. The bulb in question happened to be a 24v truck tail light item, but surley the voltage and wattage is pretty unimportant as I can control them both at the power supply, or am I wrong ?
When I measure voltage at either side of the bulb I was getting the correct 3v at the power supply side, but at the annode side of the bulb I was only seeing 0.12v. is this normal or do I need to achieve the recommended 3v accross the annode and cathode ? I tried downsizing to a 3v lantern battery and once again I only saw 0.39v at the annode.
My attempts at plating copy cad have been dismal, despite having had superb results with my nickle set up.
My copy cad always comes out dark grey and I have to polish it with steel wool after plating to get any kind of shine, If the set up was operating correctly and the parts where polished before the plating process, should the come out of the tank shiney, or do you always have to polish the parts afterwards ( I am using brightner )
My annodes have both turned almost black now, is this normal ? I have tried a 500ma 3v regulated power adapter which should have done the trick but after around 2 hours of plating time the was no sign of a deposit of zinc at all.

My main question is when the kit recommends say 3v and .25 amps and I can send this to the tank, what voltage should I be reading accross the annode and cathode. I know that they are completing the circuit through the electrolyte but does 0.12v sound correct ?

[seanc]

Rab:

This issue has been discussed many dozens of times. Do a search on this forum for "CopyCad", Copy Cad", "zinc", "power supply", etc., and you'll have more information than you can read in a day.

Having said that, to get you going quickly:

1. get some masking tape
2. put it over the volt meter
3. turn the volts knob half-way (more than enough for a 50v supply)
4. set the current to whatever is needed for the size of your parts
5. plate away

Voltage is IRRELEVANT. Do NOT try to set voltage, it will self-adjust to whatever value is necessary for the amps you specify.

ONLY set the amps, ignore voltage.

Now, if you want to know what the voltage has settled in at, remove the masking tape and see. In the small 1.5-gallon kit, you're never likely to get above 1 volt.

Sean

[Rab]

Thanks Seanc, you are the man ! I am starting to get my head around the circuitry now !
I am having better results now I am ignoring the volts, and my surface area calculations were also wrong. My plating is still comming out really dark though, but shines up really well with a wire brush. As you say the amps per square inch that Caswell recommends seem too low, what is the difference between the old kit and new kit ? mine was bought in England about a year ago and the electrolyte came in concentrated form ( no dry Pack of Cyrstals ) which kit have I got, and how many amps per square inch and temperature do you recommend for me ?
In My plating manual there are two pages with the instructions for copy cad / zinc kits, and they both have conflicting instructions for current !
Caswell seems to recommend 1A x 40 square inches which is 0.025A per square inch ? that seems very low to me, I think I read on your page that 0.05A per square inch gave the best results, but others on the forum have talked of using 0.1A per square inch.
For some reason I Never get any bubbles or fiz comming from the part, I have watched the video on your site, I even tried cranking the Amps way up on a test piece and still no fiz - What gives ? could this be related to my dark plate problem ?

[seanc]

Rab:

I don't know if the UK kit chemicals are different than the US ones or not, so be sure to check with Caswell first. I can't say if you have the original or new formula electrolyte.

Even in the US, the electrolyte is a liquid concentrate, not dry crystals. Once mixed w/water, there is no visual difference. The original concentrate was @ 1/3 solids that had settled to the bottom of the bottle. The new concentrate is @ 2/3 solids. That's the only way I know of to tell the difference.

With the original formula, temperature should be between 60-90º F (15-32º C), and current density between 75-100 mA/sq-in. (.075-.100 A).

With the new formula, temperature should be 110º F (43º C), and current density 140mA/sq-in. (.140 A).

With the brightener added, your parts should come out bright silver. If they're still coming out dark, it's likely your current is either too high or too low.

Fizzing is not a reliable indicator, as it varies greatly depending in total size of parts, temperature of bath, current density, and distance between anodes & part. However, there should be some fizzing. Even very small parts will fizz, but it's very slight.

If you crank the current way up, it should be fizzing furiously. If this doesn't happen, then something else is wrong.

Sean

[Rab]

Thanks Seanc, I am doing some more test pieces over the next few days, I just plated a part of 60 square inches, and discovered in my manual that 2 pages past the first set of cad/zinc instructions, the second set that conflicts with the first is for the concentrate electrolyte which I have, it recomends .002 amps per square inch, so 1.2 amps for my 60" part, using the calculations that you have stated ( and I dont doubt your wisdom in the slightest ) I should have been using up to 8.4 amps for this part, if I have the new kit mabey this is why I am having no fizzing ! Why the huge difference in power recommendations. I will dramatically increase my power and do some tests.
Will let you know how it goes

[seanc]

Rab:

I just plated a part of 60 square inches

WHOA! You hadn't mentioned how big the parts were before.

How many square inches of anode are you using? You need total anode surface area at least double the size of the parts.

it recomends .002 amps per square inch, so 1.2 amps for my 60" part, using the calculations that you have stated ( and I dont doubt your wisdom in the slightest ) I should have been using up to 8.4 amps for this part , if I have the new kit mabey this is why I am having no fizzing !

Yes, that's nowhere near enough current, and would account for no fizzing.

With the original formula, 60" will need at least 4 amps, but will plate best between 4.5-6 amps.

With the new formula, it will need 8.4 amps.

Why the huge difference in power recommendations.

In a nutshell, the original recommendation of .025 amp/sq-in was not based on electrical measurements, but simple math.

The original power-brick supplied in the kit was RATED at 300 ma., and sufficient for 12 sq-in. Doing the math, you get 25 mA/sq-in.

However, IN ACTUAL USE, while plating 12 sq-in, that power brick truly produced 800 ma! 800 ÷ 12 = 67 ma/sq-in. Not coincidentally, 67 ma/sq-in is the minimum current recommended for the electrolyte.

Sean

[Rab]

Hi Seanc, my part is not that big, is it ? help me put my lack of confidence in my math to bed . Am I working this out right ? my part in question is 6"x5" and I am plating both sides so I multiply x2 , = 60" is this correct ?
If I am correct then I now do have a power supply problem as my bench top supply only puts out 3.12A max.
I tried the piece this evening at my max 3.12A and saw a little fizzing for the first time, it turned out with shiney nice plate on a few areas but still dark on others, so I think I am heading in the right direction, looks like I need a bigger power supply and some more anodes. Can I buy regular zinc anodes from another supplier, or do I have to use the Caswell ones ?

[seanc]

Rab:

my part is not that big, is it ?

It is too big for the original small kit. Your part size will be limited by either available power, or anode size.

= 60" is this correct ?

Your math is correct. Now, how big are the anodes?

If I am correct then I now do have a power supply problem as my bench top supply only puts out 3.12A max.

That's enough for about 45 sq-in MAXIMUM using the old formula. You will be on the ragged edge of unacceptable plate though.

It's enough for 22-25 sq-in using the new formula.

I tried the piece this evening at my max 3.12A and saw a little fizzing for the first time, it turned out with shiney nice plate on a few areas but still dark on others

Now you are getting somewhere. Fizzing is good. A 60" part should produce quite a bit of fizzing. The patchy plate you describe does sound like your anodes are too small for the part.

I suggest you try a small part, well within the limits of your power supply and/or anode size, then you'll know what a good plate looks like.

Have you determined yet if you have the original or new formula? Did your kit come with a small AC power adapter? If it did, it's most likely the early formula. The new kit does not include a power adapter.

However, since you are getting kit in the UK, I don't know what the differences might be.

Sean

[Rab]

Hi Seanc,

Okay, Now I am learning ! Ok so my anode`s (1x 4"x8" cut in half) are nowhere near big enough for thye larger part that I was trying to plate, although I did get nice plates on part of it !

I decided as suggested by yourself to scale everything down, I had 8 times 7/16" flanged base nuts to plate, instead of doing them togeather or even four at a time, I done them all individually, I calculated surface area to be 3.5"
and with the recommended 20Ma per inch recommended in my instructions nothing happens, having had much better results working at around your recommended 100Ma per inch I plated all eight at 100Ma increase per nut
1@300Ma,
1@400Ma, and so on, the last one at
1000Ma
to see which one came out the best, It was a close call between 900Ma and 1000Ma, so I found another similar nut and plated it at 950Ma this turned out to be the best of the bunch, but still not shiney.

950Ma on my part = 271Ma per inch !!!

That has lead me to suspect that something else is badly wrong, all Amp readings as shown on digital supplys meter where checked and confirmed correct with a Fluke multimeter.

My electrolyte solution has become very murkey and brown, It used to have an orange colour, but it is getting closer to MUD coloured now, I have been thing now that it may be contaminated, I used to have a piece of 3/16 copper tube sitting accross the top of the tank as the tank bar, sometimes this bar would have been soaked in electrolyte either by my gloves, or occasionally by over inthuisiastic agitation fro my air pump splashing up on it, the copper tube corrodes and turns green, but if the tube gets wet again the green corrosion was washed off -- into my plating tank !

What is the chemical composition of the green copper corrosion?
Has this possibly caused all my problems?
Is my electolyte ruined?
Is there any way I could filter the pollutants?

[seanc]

Rab:

950Ma on my part = 271Ma per inch !!!

That has lead me to suspect that something else is badly wrong

That's certainly WAY over the top. In the test I did a while back, parts started burning at 150 ma. Are you reasonably sure of your part size calculations?

You are aware that the "brightener" gets consumed during plating? If you tried to plate that 60" piece often enough, your brightener may be depleted already. You may have to add more.

My electrolyte solution has become very murkey and brown, It used to have an orange colour, but it is getting closer to MUD coloured now

It does that normally. Mine is the same. It does not appear to hurt anything, though it makes it difficult to see the parts.

Is my electrolyte ruined?

I wouldn't think so.

Is there any way I could filter the pollutants?

Coffee filters work, but you need a lot of them (they plug up quickly) & it's time consuming.

Charcoal water filters also work. I use a plastic tubular drinking water filter, plumbed in to an agitation pump, w/outlet dumping right back into the plating tank. It takes a while to filter that entire 3 gallons, but clears it up nicely. I don't do it but once a year.

Either method will remove most of the brightener as well, so be aware that you'd have to add it back in.

Sean