Pickle not working

[Sheen]

Intially using a vinegar and salt solution worked well, then i was having pieces go a mucky brown grey colour. Switched to a hotpot of alum, but didn't remove the mucky colour. Was my vinegar contaminated or is this firestain?

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[Dennis]

Generally pickle leaves a duller colour when the solution becomes very concentrated due to evaporation.
It can be revived by adding water.
Alum solution needs to be used fairly hot.
Gently heating your pieces and dropping them in pickle will improve the colour, but of course you will be polishing too I guess.
Alternatively a wet and soapy brass brush will clean them up Dennis.

[Sheen]

That's what's getting me with the mucky grey colour its adhered pretty solidly a brass brush struggles to remove it. I've resorted to getting it off with sandpaper.

[CJ57]

It shouldn't look like that after it comes out of alum, it should be milky white. What is your container made of Sheena?

[Sheen]

Hi caroline, it looked like that after coming out of the vinegar and salt pickle (it stopped working after i got a little impatient took a item out gave it a wee sand then put it back in again, maybe contaminated by sandpaper or soap? Alum didn't correct the colour. So have now ditched vinegar mix.

Bought a slow cooker with a ceramic liner. Put two table spoons of alum in with some water. How long do you heat it for? I have a high, low and warm setting on my cooker. Going to try a new batch of silver next.

[CJ57]

It doesn't matter how hot it is, I get it up to heat and either put it on low or turn it off as my lid starts to rattle. Make sure you have lots of water as it'll dry out quite quickly if you have it on for ages. I just chuck alum in, I've never measured it as long as it comes out the colour it should I'm happy.
The receptacle you were using might have been responsible for the colour, it should work well with ceramic

[Sheen]

Thanks caroline, will let you know how a get on once i've stopped burning my solder paste and have a new batch to pickle.:-D a hot day today.

[Sheen]

Put some silver and copper in my pickle pot, the silver came out nice and white but the copper came out a dirty red/brown colour. What's going on? Does alum work with copper?
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[Dennis]

My reply, 20.04.18.

[CJ57]

My OH puts copper in alum pickle and it comes out a matt pink which polishes up really easily with a wire brush. Not sure why yours is coming out that colour, does it not rub off with your fingers under the tap?

[Sheen]

Hi Caroline and Dennis, i used the alum in a crock pot where the alum started to steam. I haven't had many items in the pickle so the concentration must be okay. The dark colour doesn't rub off easily i tried soap and toothbrush, brass brush and eventually went with green scrubby and bon ami to remove it. Caroline interesting that it should come out matt pink in the alum, suggests there's something i'm doing wrong. As long as i know the alum should work for copper then hopefully i'll figure it out:o.

[Dennis]

What I would do then Sheena, is to make up a new hot alum solution, gently heat the copper without melting any solder joints and drop it in. Should work. Dennis.

[Sheen]

Thanks Dennis, will give it a go with my next batch. The last lot of things i made i really enjoyed the soldering, i feel like i'm making progress.

[CJ57]

I should say Sheena that his copper isn’t soldered only fold formed and I have no idea if that makes a difference. I’ve given him his own batch and he boils it up on a stainless steel pot on the gas.