I need help with my chrome plating kit!

[advantagetech]

My name is Kelly Pichel and I own a small electroforming company. I specialize in electroforming small optical reflectors for hand held search lights,dust particle counters and other various uses and I recently got a job electroforming ophthalmic eye glass molds. Most of my reflector business requires the pure nickel reflectors to be plated with Rhodium which is very easy to use, or I send them out to get an enhanced aluminum vacuum coating. The eyeglass company wants there molds chromed. Since they are my only customer that needs chrome, I didn't want to set up a large industrial plating line and that's when I found caswell.

I set up a plating station and hung my anodes in a way that I can move them closer or farther away from the mold I am plating. The mold looks like a flying saucer cut in half with the convex side being optically polished so I can't buff or touch the surface with anything. I put the molds in an ultrasonic cleaner and then I put them in an electrolytic 10% sulfuric activator ( I also tried dipping them in 10% hydrochloric acid with no power and it did not help). I use ultra pure D.I. water. My surface area is 17.25 sq in. I go into the bath hot but with the power low and then I turn it up. I have been experimenting between 12 and 16 amps. sometimes I get some coverage on both sides but the polished side is streaked with white wash. Most of the time the back is partially covered but sometimes there is nothing. I have anodes on both sides.

Can somebody give me some pointers?


Do I need to take the anodes out every day, and if so do I need to treat them with something? I have tried to plate about 30 molds and I have only been successful with two, and those two were in the beginning. The next one that I would do the same would come out stained white on the optical side.

Please let me know if you have any advice.

Thanks

Kelly Pichel[/quote]

[mcaswell]

Firstly, do you need to plate both sides?

If not, then set the anodes to plate only one side.

Is the 17 sq " counting both sides?

16 amps for 17 sq" may be a bit low.

Temp of tank is also important, as is the closeness of the anode.

Have you attempted to plate the copper tubes as per the manual? Did you get a good result with this? If not, forget your project and get back to basics with the copper tube. Get that right before doing exotic stuff.

[advantagetech]

I do need to plate both sides. I have tried more ampe but got the same results. As far as the brass pipe, It came out good all thrree times that I tried it.

Thanks for your input.
Kelly

[fxstcguy98]

Kelly,
First dummy plate the chrome bath to get it activated as per the Caswell manual. Prepare the part as before and make sure you pass the water break test. Don't go in hot, put the mold in the bath and let it sit in there for 2 or 3 min. without power. Then turn on the power at 17Amps for 3 min., Don't ramp it up. Make sure you have good connections to the part and don't jiggle it or remove it during the process, it will not continue to plate. Hope this helps
Darrin

[mcaswell]

Try moving the anodes up close to the part, say about 2-3" away.

[advantagetech]

Thanks for the info, I am setting up my tank. I bent a dummy and am going to have a system set up in a couple of days. What asf do I run the dummy? Does it matter?

Thanks again for your help.
Kelly

[fxstcguy98]

Dummy just as you would plate at 1amp/si surface area. A 4"X6" dummy would be at 48amps (both sides).

[advantagetech]

How do I filter my chrome bath? I have a Rhodium bath that I filter with a small acid resistant pump and a small filter chamber. This circulates the solution keeping the temp constant and also filters down to 5 micron.

I need to know what type of filter material will work without eating the filter. I tried pouring it through watmans paper but it burns the paper and it falls apart. Since I am working with optically polished surfaces, I need my deposits to be as pure as possible.

Kelly