re: Beer Neck Knives

I apply the mask and then I have contact that's covered in felt.  I soak the felt in salt water then apply it with DC current with the positive lead clamped to the knife blade and the negative lead going to the felt-covered contact.  I do this until the etch is the depth I want.  For me it's about 25 seconds but it will depend on the actual current and voltage you are using.  Then I have a switch that changes the output leads to AC.  I apply in the same manner for about 30 seconds to darken the etch.  That's it.  You have to experiment with contact times depending on the type of metal you're etching and your actual AC and DC voltages and currents.