HCL-CL dissolve brass??

[amosfella]

Title says it all... Would HCl-Cl dissolve brass or copper??

 

[Harold_V]

It rapidly dissolves the zinc contained in the alloy, so even if you don't achieve a fast dissolution of the entire body, it is degraded.

While I have not ever used any of the work-around processes that are widely supported on this forum, seems to me the addition of a small amount of hydrogen peroxide is all it takes for HCl to dissolve copper readily. Might pay you to do a search on the subject. If I am mistaken, feel free to post a correction.

Harold

 

[amosfella]

I was looking for a method to strip gold plating from brass without dissolving the brass or copper underneath... Preservation of the substrate is not an issue... Just want the cleanest way to get the gold...

 

[jimdoc]

What is it you are trying to strip?
Maybe the sulfuric cell will work.

Jim

 

[amosfella]

sheet plated with gold, and pins. All have gold on them.

 

[Militoy]

I’m a noob when it comes to processing, so I’m sure there is probably a better method – but the simplicity of AP appeals to me – and it definitely works on 360 brass, as long as you aren’t in too big a hurry. I started in straight 10 molar HCl and got a pretty good reaction, with the (cold) acid outgassing and turning greenish right away. The acid turned deep emerald green by the second day of soaking with an occasional stirring. On the third day, I added more acid and most of a bottle of 3% peroxide. On the fifth day, I decanted the liquid through a filter and added fresh acid/peroxide to the remaining pins. After about a week, all the brass pins were dissolved, leaving the plating behind, along with some ink and dross to clean up. I’m running my more recent ones using a little heat from the crock pot, and combining a few batches of foils to run in poor-man’s AR. I didn’t detect any dissolved gold in the leftover liquid – but am planning to cement the various leftover metals just to familiarize myself with the process. The photos show a pound of the kinds of pins I started with; and the foils from about ¼ pound of them in a filter.