Very interesting, GT. I hadn't seen this one before. It's basically a method for separating the karat gold layer from the substrate of gold-filled materials. It uses a 304 or 316 SS cathode and a very weak nitric/distilled water solution. The gold filled material is the anode. The karat gold layer is undermined and flakes off. Supposedly, the copper base isn't appreciably attacked and what copper does dissolve deposits on the cathode. Also works on nickel and other base metals. Might work well on stainless watch bands. Might work on gold plated materials.GTmurph said:I couldn't find anything with a couple forum searches and I was wondering if anyone had ever tried a HNO3 cell similar to the one described in this patent, http://www.freepatentsonline.com/4606797.html?
You're right. It says, preferably, between .02-1%, but MOST preferably, between .03-.06%, and ideally .05% - that's only .5ml (about 8 -12 drops)/liter. Most straight glass eyedroppers from the drug store will dispense about 23-25 drops per ml. You can determine the drops/ml from any eyedropper by counting the number of drops of water it takes to weigh 5 grams and divide by 5 or, weigh 2 grams and divide by 2, although that's not as accurate.FrugalRefiner said:I read through the patent as well. Very interesting. It mentions a couple of times that the 2% is the upper limit for the nitric and that the preferred concentration is actually 0.03% to 0.06%. I'm not sure that's concentrated enought to even yellow the skin. :shock:
Certainly sounds safer than the sulfuric cell.
I can't wait to hear someone try this! Especially if it can work on gold filled.
Dave
Great first post GTmurph!
Geo said:if i read the patent correctly, its not the nitric acid that removes the gold but rather copper nitrate. i may be wrong but from what i got out of it the color change is to be expected.
GTmurph said:@GSP: A sheet of nickel plated on one side. I'm sorry I can't really say anymore.
GTmurph said:@Geo: I don't think so because the author mentions various base metal substrates where no copper nitrate would be present. From my understanding the nitric is dissolving the base metal beneath the gold which thereby delaminates it.
etack said:GTmurph said:@GSP: A sheet of nickel plated on one side. I'm sorry I can't really say anymore.
This should give you a green solution. as Nickel dissolved in nitric is green. your not dissolving that much so it should be light.
GTmurph said:@Geo: I don't think so because the author mentions various base metal substrates where no copper nitrate would be present. From my understanding the nitric is dissolving the base metal beneath the gold which thereby delaminates it.
etack said:this just seems like an ion exchange to me. as when the X metal substrate is dissolved in the nitric it is then plated back out on the cathode as X metal. Nitric is used cause it wont exchange gold ions.
Will have to try it.
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