What the ****?! Blueish zinc electrolyte??!!

[paskharen]

Hi!

I have casted my own sheet anodes from some zinc pellets (99.99 %pure) and started up my bath today. I was doing everything as i always do cleaning, rinsing pickling and so on. I plated one batch, beautiful results. Started up a second one, went inside the house for some coffee and returned to the plating tank after 15 minutes. I looked in the tank and thought, hmm... thats strange, the electolyte seems to have a blueish coulor to it. With a closer inspecton i noticed some blue powder like stuff on the side of the tank (waterline). I took out the parts i was plating and discovered that they had black spots on them.
What the heck has happened?! I belive its a copper contamination, but how?? Could copper have leeched in to the anodes when i casted them? I didnt use any copper i the casting process.....

[woodjames]

Without knowing the exact process you used that's going to be tough to answer. You'd be best off to keep the pellets as is and get an anode basket for thiem.

[paskharen]

Yeah... Seems like i have to learn everything the hard way,messed up electrolyte, a lot of swearing, tools flying across the room. I should have sticked to the pellets, but since i didnt have a basket and was eager to start plating again i thougt casting them was the next best thing. Apperantly not.. I milled the casting mold from two steel plates and melted the pellets in a steel bowl. I probably went wrong with the steel... Right now i feel like throwing all the plating equipment on the pickup truck and drive it to the dump. But i'll probably wont.... i think...

[woodjames]

Dog running the other way, and everyone else around the vicinity running in to make sure everything is okay? I've been there.


You can save a bath from practically anything, get some good zinc back in there and just start dummying. If it's copper, during an idle period it'll build on the anodes. If you put zinc dust in the bath, the copper will immersion plate on it too, which is better yet, but you need to get it out quickly afterwards by decanting/filtering.

If you need a basket, lemme know, we can work something out. I've got a few extra kicking around, and I've gotten pretty good at re-working them to better sizes.

Yeah... Seems like i have to learn everything the hard way,messed up electrolyte, a lot of swearing, tools flying across the room. I should have sticked to the pellets, but since i didnt have a basket and was eager to start plating again i thougt casting them was the next best thing. Apperantly not.. I milled the casting mold from two steel plates and melted the pellets in a steel bowl. I probably went wrong with the steel... Right now i feel like throwing all the plating equipment on the pickup truck and drive it to the dump. But i'll probably wont.... i think...

[paskharen]

Yes, you told me earlier about zinc dust and i really need to get some of it. But as a do-it-your-self guy i wonder if i can make the dust myself by...... hmmmm......sanding a zinc piece?

[woodjames]

problem is sandpaper breaks up and you'll get too many particles in there, but a file....
just keep it contained, like do it all over a plastic bag, with a clean! file (no oil) with no rust.

Yes, you told me earlier about zinc dust and i really need to get some of it. But as a do-it-your-self guy i wonder if i can make the dust myself by...... hmmmm......sanding a zinc piece?

[paskharen]

What kind of zinc dust should i use? (microns) And should i do something special to the electrolyte, like heating it, stirring and how long would it take for the copper to plate on to the dust?
I will email you about the baskets later Jimmy..

[woodjames]

Size isn't that important. You're just aiming at having a lot of surface area for the copper to plate out onto. Finer dust = more area. Larger pieces will work, you'll just have to do it a few times. Pretty much just trial and error. Wish I had some exact numbers, but it is what it is, and you'll just have to keep at it 'til it's mostly gone. Even if you get it close, just dummy it out. The anodes themselves will pick-up copper the same way as dust will, watch for deposits on the anodes when no power is on. Take them out, scrub off the darkness, then put them back in. You should be able to do it at room temp, no agitation, stirring will help distribute the particles better. The copper will begin plating out onto them immediately. But since you're trapping it, you need to get it out quickly. You could even try to put the dust in a stocking, swirl it around for a while, inspect. Put new dust in the stocking, swirl it around in the tank awhile...repeat as necessary. That way you wouldn't have to filter much.

To dummy, take a piece of steel, and bend it like an accordian. It should be 1/2 the size of your anodes - the good ones
Run it like any other piece, except with the following cycle - one hour at 3 volts, an hour at 2 volts, an hour at 1 volt, then 5 minutes at 5 volts. Don't pull out and inspect too often, as loose particles will drop back into the tank. If you do pull it out, just run it at higher voltage for a few minutes to "Lock Down" the loose stuff.

That should get things back to normal. Sounds good on the baskets, I'll watch for it.

What kind of zinc dust should i use? (microns) And should i do something special to the electrolyte, like heating it, stirring and how long would it take for the copper to plate on to the dust?
I will email you about the baskets later Jimmy..

[paskharen]

Thanks again Jimmy, but you only mention a wide range of voltage when dummying...what about the current? Should it be run at low current?

[woodjames]

Pay no attention to the current, as the piece will draw what it needs, and the higher voltage will bring higher current, and the lower voltage will draw lower current. If you're still using that ni-chrome or whatever now's the time to get rid of it, and just go direct with the rectifier. Just watch the output, you'll see the amps jump with the voltage. There's a Faraday law to explain it.

Thanks again Jimmy, but you only mention a wide range of voltage when dummying...what about the current? Should it be run at low current?