Etching resists brakes down

I could use some feedback. I frequently etch fine silver in ferric
nitrate, I’ve used PnP, ImageOn Ultra and paint pen. I get a
fabulously detailed etch, but the resists begins to brake down
before it can get deep enough for my use- one nice layer of enamel.
I have tried: giving the resists a day to sit, new acid vs slightly
used acid, heated vs non heated. Should I switch to Nitric acid? Any
help would be appreciated.


Several things you might consider when working with PnP: Make sure
the PnP has a dark navy blue color. After the initial transfer, if
it’s not dark blue, and leave it on the heat source until it does
turn dark blue. The other is that PnP sometimes loses the color in
the resist, but that doesn’t mean it’s not still there. Check things
carefully with a 4X power Optivisor. Be sure your sanding is all in
one direction. Cross hatch sanding can cause the resist to lift.
Make sure the metal and the PnP is super squeaky clean. Even the
smallest amount of oil can affect the results.

PnP Blue will not hold up to nitric acid. If you are looking for
depth for champleve enameling, how about copying out 2 designs of
PnP Blue resist, use one, then when you see that you are not at the
depth you want but still don’t have breakdown of the resist, put the
second copy over the first (after washing the surface well) and heat
adhering it over the first resist. If you want that depth, another
alternative is to get some sheet wax and carve your design, then
cast in fine silver.

Donna in VA

Katherine, thank you I have not thought to only scrub in one
direction. Due to the manner in which the resist lifts off this
could be a key. I also got an offline response discussing the
strenght of my ferric nitrate (500 grams to 1 pint water) being too
strong. I could use any other tips anyone has. Not etching is not an
option, while i do cast plenty of work, I have a great need for
etching success.


What you need for maintaining a clean deep etch is Dragon’s Blood…
no, I am serious… it is a red resinous powder which is/was much
used in the printing trade for preventing undercuts in etched
printing plates.*

dragon’s blood

Powder applied to the relief portions of a metal printing plate
by using heat, so that the powder fuses with the plate's surface
and protects the covered areas from damage caused by acid that is
used during the printing process. Dragon's blood powder is made
from the fruit of the rattan palm." 

also see Zinc Engraving Or Etching for more description…

Now where’s that dragon - my stocks are running low…!

Best wishes,
Ian W. Wright
Sheffield UK

I also got an offline response discussing the strenght of my
ferric nitrate (500 grams to 1 pint water) being too strong. 

Sharon, if you’re really going to do a bunch of etching, it will pay
you to invest in a Baume’ hydrometer that measures specific gravity,
in the range of 15-60 degrees. Different grades of ferric nitrate, as
well as different manufacturers, will not be equal in the strength of
the ferric nitrate by volume or weight. You want a stronger solution
that bites fast and deep for fine lines. You want a weaker solution
for a slower bite in areas that have lots of open (negative) spaces.

Also be sure to use distilled water to make your solution, as regular
tap water contains contaminants (iron, lime, calcium) that will
affect your etching results.

Dear Sharon, There are more powerful resists. Not as convenient, not
as fast, but very strong. You might look to Kodak for some guidance.
Computer chip technology is all based on photo resists so there is a
lot of info out there.


Bill, Deborah & Michele
Reactive Metals Studio, Inc
928-634-3434, 800-876-3434, 928-634-6734fx