Dennis,
When I was experimenting with this, I had corresponded with Dr. Gaddy. What was unclear was the actual strength of the FeCl He gave me percentages, but I didn't know they were based on starting with a Radio Shack circuit board etch which is only 41% FeCl
So my experiments finally fleshed out that one part 41% strength circuit board etch diluted at least 6 parts water will work with a 10 second dip and immediate water flush with a wet carding of 000 or 0000 steel wool. 8 parts water will give you a little more time in the etch dip.
Or about 6% actual FeCl strength. As Kuttler pointed out, 3-4% works. Stronger than 6% and dwell gets too short.
I think Bertram had gotten around to doing it and would have more experience than I by now.
Last edited by Chuck H; 01/03/17 07:11 AM.
