This patent may have already been discussed on the forum. It sounds vaguely familiar.
I just discovered this patent and found it quite interesting and simple. It is a fast electrolytic method using about a 1% nitric acid (about 10ml/liter of 70%) solution in good quality (they say at least 5 megohm) distilled water. They say that 2% nitric is the maximum that should be used. It operates fairly hot (best is between 150F and 195F, they say), making the part the anode and using two stainless sheets wired together (one on each side of the anode) as the cathodes. The spacing between anode and cathode should be at least 2" and preferably more. The voltage and current density have wide spreads. The time is from 5 to 25 minutes.
According to the patent, the karat gold layer blisters and falls off (still as karat gold) in at least 1 cm sized pieces without seriously affecting the substrate. It supposedly works on many different substrates, including stainless (watch bands), nickel, and copper alloys, although copper will be slightly attacked. They say that the acid penetrates the gold layer and attacks the bond between the gold and the substrate.
About 10 years ago, when I was fiddling around with making colloidal silver, the best distilled water I found was the higher priced variety from Walgreen's, about $1.50/gallon at that time. At least, it was the only brand that gave zero current flow measured on a milliammeter when beginning the electrolysis of the pure silver.
In the patent, they use constant filtration to collect the gold flakes but, if I were to try it, I would just let it go and then filter the solution at the end. Good success, of course, would be if all the gold falls off and you don't have to mess with it to get some of it off.
The nitric will probably become less concentrated over time. Were I to try this, I would periodically analyze the acid content and make necessary additions, without exceeding the recommended 2%.
The patent is well written and contains much more detail than I have given. The examples near the end are very good.
If anyone tries this, please report your results.
I just discovered this patent and found it quite interesting and simple. It is a fast electrolytic method using about a 1% nitric acid (about 10ml/liter of 70%) solution in good quality (they say at least 5 megohm) distilled water. They say that 2% nitric is the maximum that should be used. It operates fairly hot (best is between 150F and 195F, they say), making the part the anode and using two stainless sheets wired together (one on each side of the anode) as the cathodes. The spacing between anode and cathode should be at least 2" and preferably more. The voltage and current density have wide spreads. The time is from 5 to 25 minutes.
According to the patent, the karat gold layer blisters and falls off (still as karat gold) in at least 1 cm sized pieces without seriously affecting the substrate. It supposedly works on many different substrates, including stainless (watch bands), nickel, and copper alloys, although copper will be slightly attacked. They say that the acid penetrates the gold layer and attacks the bond between the gold and the substrate.
About 10 years ago, when I was fiddling around with making colloidal silver, the best distilled water I found was the higher priced variety from Walgreen's, about $1.50/gallon at that time. At least, it was the only brand that gave zero current flow measured on a milliammeter when beginning the electrolysis of the pure silver.
In the patent, they use constant filtration to collect the gold flakes but, if I were to try it, I would just let it go and then filter the solution at the end. Good success, of course, would be if all the gold falls off and you don't have to mess with it to get some of it off.
The nitric will probably become less concentrated over time. Were I to try this, I would periodically analyze the acid content and make necessary additions, without exceeding the recommended 2%.
The patent is well written and contains much more detail than I have given. The examples near the end are very good.
If anyone tries this, please report your results.
