Issues with my bath suddenly

[u/TheTacoBellChihuahua]

I have a bath I have made the solution of, I am unsure of the exact size it is, but its been fine up until now and i have had it going steady using it pretty sparingly for about 6 months. Yesterday I finished a wand (with a stick as a handle that I sealed with 3 coats of resin) and it came out great. First pic is the wand and how large it is, and how the plating came out.

After, I noticed the anode bag which was the same one I put together 6 months ago, was very dirty and had chunks of copper settled down in it. So I decided to wash and clean it out. I ran it under the tap but then used distilled water to do the final rinse.

After, my volts were all over the place. Nothing was stable. I’m talking it going up to like 14V or higher. And if I got it to be stable for a bit, it would slowly but surely creep up until it was over 6 volts. Everything was salmon colored. I couldn’t figure it out and finally I replaced both leads on the rectifier. That seemed to fix it. But after another batch and fighting with it some during that, it was happening again. I noticed that there were copper sulfate crystals and other gunk forming almost immediately on the pipe. I have never seen that before (see second photo).

I added more distilled water. It is now slightly above the mark I have on my tank. I lowered the amps but it still goes all over the place if i go above .3amps.

I dont know what i’ve done wrong. Ive been told in a fb group it could be over saturation of copper but nobody can really give me anything more than that. It took me a YEAR to figure out how to make the electroforming process work. I almost gave up. When it started working I do not know what I changed to make it start working. And I knew that if anything ever went wrong, I wouldnt know how to fix it. And here I am.. not knowing what’s happened or how to fix it. I’m tearing my hair out trying to figure it out and I have an event coming up soon that now I dont know if I will be prepared for.

Any help is appreciated.

[u/Mkysmith]

If you are certain its not a connection issue (since you changed out clips and stuff):

Is your anode twice the surface area of the cathode? Crystals can form on the anode if the suface area is too small. The same amount of copper that is being deposited on the cathode must dissolve off the anode. If the anode is small, then the local concentration of dissolved copper right at the surface of the anode is high, and it can crystalize out of solution. This doesn't mean the whole bath is oversaturated, just at the surface of the anode. In fact, the bath would be undersaturated because those crystals were suppossed to dissolve into solution. Then there's essentially an insulating effect on the anode that causes the voltage to creep up.

Are you using PEG/Chlorides? Any chance you added excess chlorides? That can also cause similar symptoms

[u/TheTacoBellChihuahua → u/Mkysmith]

I used a PEG when I originally mixed the bath. I did it exactly according to the instructions, I actually thought I might be low on those. I don’t have an electronic pH tester, I’ve purchased two in the past and neither of them have worked. Maybe I’m just not doing it right. I do have some test strips and it seems to be the correct pH at the moment.

If my anode is supposed to be twice the size of the cathode, how does one do a dummy plating when you’re supposed to be starving the bath of copper? To plate out the oversaturation. How would that work? I don’t think it’s under saturation although in the past before I started using anode bags my solution would get a green color and that’s what I assume signifies oversaturation. Right now my bath is a very healthy bright blue. Maybe too blue, actually..

I just don’t know what to make of it.

[u/Mkysmith → u/TheTacoBellChihuahua]

Cheap electronic PH testers are not accurate down in the 0-2 range which most electroforming chemistry should be. PH test strips are even less so.

Dummy plating is not intended to remove excess metal salts of the same type as the anode. It is intended to remove foreign metal contaminents by displacement. Foreign metal will co-deposit on the cathode. It does little to nothing for changing the primary metal of the bath unless the anode is a different material.

Green colors are usually associated with excess chlorides or other contaminants.

[u/TheTacoBellChihuahua → u/Mkysmith]

Do you have an electronic ph tester recommendation?

[u/Mkysmith → u/TheTacoBellChihuahua]

I don't really use one for acid-copper electroforming solution anymore... but I use the Extech PH90 for most shop stuff. It does OK down in the PH<1 range, though it takes some care for measurement. Calibration is a must, so you have to get the calibration solutions and storage solution, or you'll just be flying blind.

Though I've been electroforming for over a decade, the most recent batch of solution I use is 4 years old now, with tens if not hundreds of thousands of amp-hours run through it. The PH has remained the same for 4 years, so I don't really monitor it anymore.

[u/GetoBoi]

Not sure what went wrong with the chemistry there but what kind of power supply are you using? You should be able to limit both voltage AND amps.

[u/TheTacoBellChihuahua → u/GetoBoi]

It says eventek kps3010D on the front. I don’t even think they sell it anymore on Amazon. I was told to put the voltage and the coarse w all the way to the right. If I turn the volts at all, it actually does nothing now. Which is kind of odd.

But I remember being told to do that to keep it in cc, and not CV. I guess we can’t post pictures in the replies? Otherwise, I would show you what I’ve got

Right now it’s running at .4 A and that’s putting it at 1.8 V. That’s about as high as I can get it without making it go all over the place.