maynman1751 said:
SBrown said:
Did you remove the soldering mask?
Soldering masks may prevent the gold from being foiled off. If you didn't remove the soldering mask, you might have a difficult time coaxing the soldering mask of. At this point, because you already started processing the PC boards, you should probably take Geo's advice. By cutting into small pieces it makes it easier for a solution to get at, or underneath, the gold.
I did about the same thing with plastic chip packages fairly recently. I shredded them into small enough pieces that my solution could get at the internal structure from the sides, and it worked awesome.
Scott
Hey Scott! (I got it right this time 8) )
I depopulated the board and stripped off the solder mask and threw it in with the first batch.
Too funny, I am going to copy and paste names from now on so I don't mess any up.
If you look at his pictures, the top one with that hand wearing the glove. Look to the right hand side, you can see an area of the board that has nothing on it at all, it's totally bare, right on the right hand edge. If you look just to the left of that bare spot, you will see a shiny reflective surface. I believe that is some type of soldering mask.
Sometimes on older electronic boards they used a shellack type of material that is more difficult to remove than the normal soldering mask you usually come across. I had some boards with really heavy gold solder like what I posted below. These boards are all late 1970s. If you look, you can see the heavy soldering mask.
Here are a couple boards with the type of soldering mask I am describing.
You can see the solder mask I am talking about on this board, it was applied after components were soldered to the board, when I removed some of them I took this picture go show how the shellack was applied.
Here is a board that I had to process a second time with the lye past, because only part of the mask was removed. If you look at the bottom left, you will see the part that wasn't removed, and the difference between the parts that the mask was removed, and the parts that were not.
I ended up making lye paste to brush on these boards in order to get the soldering mask off. It was just simply too thick. Here is a cleaned board, what it looks like after the soldering mask is removed.
Scott