Dmitry,
For the boards in question I use a large rectangular plastic cake carrying pan. I put enough HCl in the pan to cover the bottom about 1/2-3/4 ". I then add in a board and sink it under the HCl. Next I pour in 3% peroxide making sure to move around the pan while pouring so the peroxide mixes with the HCl.
Then I rock the pan a few times to mix everything nicely.
Within a few minutes the solution will begin to turn yellow green.
At this point I take an old tooth brush and buff the gold plating off the board. When the gold comes off it typically is so fine that it immediately dissolves.
After doing both sides, I pull the board out with a set of plastic or wooden tongs. Rinse the board into the pan with a spray bottle and insert a new board.
If the solution doesn't react quick enough or quits working quickly with the gold, I add more peroxide.
This process is different than your typical AP reaction in that the goal is to dissolve the gold, not the base metals. Since the gold is so fine, it's very easy for the strong peroxide mix to attack the gold.
Once all the boards are processed, I add enough peroxide to dissolve any remaining foils. The solution appears a clear yellow green when it's all finished.
Drop the gold with SMB.
Here's some photos:
The card on the left was stripped using this variation of the AP process, the card on the right is what it looked like before stripping. The solution in the lower portion of the photo has the gold from 35 of the circle cards stripped in it. I did these tonight in about 1 hour total time. I soaked them in batches of 15 at a time and used a toothbrush to remove the light gold plating. Each batch took about a 1/2 hour. The discs were too lightly plated to process via the standard AP route so I opted to use the quick AP method
This next photo is of one of the stripped communication boards I mentioned:
I processed this batch about a year ago.
I did several types of these boards and all of them really sucked. They are plated exactly as the cell phone boards are... barely.
I want to thank Johnny for the circle cards.
I hope this helps.
Steve :wink: