It sounds as if you’re not getting a clean transfer of the resist to
the metal. PnP is quite durable in the ferrics and even a weak
solution of nitric. I’ve responded to some of your specific problems
with some troubleshooting tips below.
with a slow solution, the ferric chloride eats through the
resist, so that the area that is protected has pitting, similar to
an aquatint. Some surfaces remain completely masked.
This is most probably from oil contamination, possibly dust
contamination. Be scrupulous about cleaning your metal before
applying the resist. Sand to 400 grit to provide a bit of ‘tooth’.
Wash with a good surfactant dish soap (my personal preference is Ajax
plain dish soap), wipe both the metal and the PnP with a lint free
paper towel (cheap brown ones are best) moistened with alcohol. After
you have the metal and PnP set up to transfer, and just right before
applying the heat, wipe both surfaces with alcohol again.
a deep etch in brass, to make a plate I can use in the rolling
Etch into tool brass (hard yellow).
Clean copper or brass (water sheets off) HP LaserJet to print
design on p-n-p
Make sure it is a strictly laser printer, not an ink jet. You must
have the carbon-based DRY toner. You can also photocopy with a
machine that uses heat-set dry toner (Kinkos have been going to the
liquid toners that are not carbon-based, therefore they don’t work).
Iron set on 3 (polyester/rayon setting)
Personally, I’ve found this isn’t hot enough. Optimum heat transfer
is around 425 degrees Farenheit. When the resist transfers, it should
be a dark blue-black in color.
Tested by etching in half-hour increments from 30 minutes to 3
hours: Test strip A in used, nearly spent ferric chloride and Test
strip B in fresh, full-strength ferric chloride. Both etched
through the mask, though A didn't start to etch through until about
I’ve had no problems etching for 8 hours or more without the resist
lifting. Undercutting is a different animal, and the strength of the
ferric can be adjusted to prevent this.