Rather thick gold plating on aluminum

What would be a safe way to remove thick gold plate from aluminum? I've got several little items that look like military stuff. It also has what appears to be a beryllium pad in the middle of the device. Would the gold go into solution if I used real dilute lye to dissolve the aluminum? I don't want the gold to go into solution. But I do want to get it off the aluminum.

Their is probably a barrier layer between the gold and aluminum. Might try a 25% solution of nitric.

If you only have a few items and you can break through the plating to the aluminum core then lye would be my go to solution.

Here is an old good thread on the subject.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177

Try plain nitric first to attack the plating between the gold and aluminium.
If that doesn't work, nitric acid with a small amount of hydrochloric might. All described in the thread above.

Göran

nickvc said:

If you only have a few items and you can break through the plating to the aluminum core then lye would be my go to solution.

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No mate. That's dissolving a big chunk of Aluminium that you don't need to. The weak Nitric is the best way as it will passivate the Al.

anachronism said:

nickvc said:

If you only have a few items and you can break through the plating to the aluminum core then lye would be my go to solution.

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No mate. That's dissolving a big chunk of Aluminium that you don't need to. The weak Nitric is the best way as it will passivate the Al.

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Not all aluminum will have a nickel barrier...I have encountered it without. Depends on how old it is. Purple plague was a real thing.

In the case you don't have a bunch of it, file it off and process the filings. If I had fifty pounds of it I'd probably set it up on my Cnc mill and shave it off....dissolving al is a pain.




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I've always used the sulfuric stripper. It works great and doesn't eat the Al. Don't let the amperage exceed about 5 amps per gallon of solution.

Hi everyone! I'm glad my brain is still functioning! Filing it is a possible option. I guess that depends on me and how much time I'm willing to put in this. So I'm going to try the weak nitric way, and I wanted to try the lye way too, but that's scary. Even on the bottle it says not to get near Aluminum. I'm living right in town now, and I really don't want Hazmat showing up at my door, first accusing me of cooking dope, and then just kicking me out of town. Happened before when I lived in Mtn. View, CA. (That was over 25 years ago!) But the lye way, seems the fast way. Can I dilute the lye somehow? Doesn't it react with water?
Also, I've found that I've got two types of metal housings. The other one is magnetic! It looks like stainless steel, but it's magnetic and doesn't get all rusty and corroded in nitric. Is it OK if I post a picture of these things?

Posting pictures is always encouraged.

Dave

Here are some aluminium plates that were gold plated. Sorry, can't find the pics with the gold still attached.

Forgot to add that I stripped them with dilute nitric acid.

Cool pics Geo - thanks for posting 8) :!:

Kurt

OK, here is a pic of the parts I want to get the gold off of.

Are you sure that is aluminum? Copper is much heavier than aluminum by volume. Does the piece feel too heavy to be aluminum. The reason I ask is because aluminum buss on electronics is kind of rare.

Well, now I've gone and switched parts. This one is magnetic. And heavier. And it's silver like stainless steel. I know it's not stainless steel, cuz it's magnetic. And it has this light pink, square pad that the porcelain hybrid sits on. I've included a pic of one I chopped with the bolt cutters. The pink arrow points to the pad. I thought it was beryllium. The black arrows point to the silver metal that the whole body is made of. But diluted nitric doesn't touch it. It doesn't phase any of it. But now that it's rinsed off, still wet, in a jar, it's covered in rust. I had thought this was going to be an easy job, just give it a nitric digest then wash the gold off the remains, then put the gold in AR and drop it. eh, didn't happen. It's the same part as in the first pic I put up. It's just off the little board and chopped.

Oh, and it's real hard to cut with the bolt cutters. Sparks happen when cutting it.

It's high nickel stainless steel. Nickel is magnetic.

Oh wow! I've never dealt with that combo before. And I usually avoid magnetics. Do you (or anybody else?), have any suggestions as to how I should deal with this? And should I have started another thread? The info for the Aluminum was Super helpful, And Thank-you all for that. Because I'm not familiar with dealing with that either. Setting up an electroplating system is probably in my very near future. (cuz that sounds a little easier than filing). ( I'm reading my Hoke's and Ammens books, but this forum, and you guys with experience under your belts, seem more helpful to me. And I like talking to you all better. )
Back to the high nickle stainless steel stuff. Like I said, magnetic stuff is something I usually stay away from. But I want this gold! There is so much of it! Since I lost everything in the fire, I had to buy everything new to work this. So now I'm determined to get it. Geo, thank-you for identifying this metal. How would you deal with this? (or would you even bother?)

Thank-you, everyone! Yvonne

Try placing the piece in concentrated nitric acid and adding HCl by the drop at a time and see if it will remove the gold before it starts attacking the stainless steel. It will work better cool or even chilled. It will be slow but you may have some success with that. If it starts attacking the stainless straight away, you will have to try something else.

Geo said:

Forgot to add that I stripped them with dilute nitric acid.

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Greetings Geo ... do you think dilute nitric would remove HDD platter foil ??? I mean the discs are said to be aluminum inside.....