PNP paper falls off during etching

Jewelry Discussion
1

I am etching silver using PNP paper and nitric acid. The solution is
3 parts water to 1 part acid.

When I lift the silver out of the bath to check its progress the PNP
paper falls off part of the silver, preventing me from replacing the
silver back into the acid bath. Fortunately, this has not destroyed
anything I am working on but I am afraid that at some point it will.
Does anyone know how I can prevent this from happening?

Thanks!
Suzanne

2

Suzanne

How are you applying the PNP to the Silver? I have found that you
must be very careful to fully bond the PNP to the silver with a Hot
iron. If not fully bonded, it will slip of fall away. You have to be
certain to get all finger/other grease of the metal before applying
as well or it will not bond sufficiently. If you need to touch up
any parts that do not adhere then use a fresh, new sharpie permanent
marker (Industrial ones are best) and go over the lines a couple of
times allowing 10 - 20 seconds between applications. You can also
use nail polish, shellac or tar diluted with naptha (use caution as
this last on is toxic).

Karen Bahr
Karen’s Artworx

3

Suzanne, PNP will not hold up in nitric acid. You need to use Ferric
Nitrate with PNP.

Alma Rands

4

Yes, this happened to me, although I was unlucky enough to have work
ruined (brutal burnishing can sort out minor errors). The problem is
that nitric acid is too aggressive really to use with PnP, try ferric
nitrate instead it’s far easier to deal with. Do a search in the
archives and you will find out exactly how to mix it etc.

Good luck
Ali
Sheffield UK

5

I am etching silver using PNP paper and nitric acid. The solution is
3 parts water to 1 part acid. PNP paper falls off part of the
silver.

When PnP first came out we did a test of various etching methods
with it in metals class. We discovered that it did not hold up to a
nitric bath; the resist was eaten away. That’s why we used ferric
nitrate instead.

Donna in VA

6 
When I lift the silver out of the bath to check its progress the
PNP paper falls off part of the silver

When etching silver, regardless of the form of resist, the resist
will hold on better if you pre-etch your silver for 1 minute (in
nitric acid) before you apply resist to it. Rinse it very
thoroughly, of course, dry it without touching the surface with your
fingers.

You can touch up resist (that didn’t come out right, or that lifts)
with paint marker, an clean, dry silver. It is not very easy to
control, especially for fine lines, but excess can be scraped away
with a steel tool when dry.

In fact, you can draw directly on metal with a paint marker and
etch. It will stay on much better, though, if you pre-etch.

Noel

7

Alma,

Suzanne, PNP will not hold up in nitric acid. You need to use
Ferric Nitrate with PNP.

Really? I did not know that. I was taught by using nitric acid. What
kind of store do I get Ferric Nitrate from or do I just order it from
the web?

8

Hi Karen,

How are you applying the PNP to the Silver? I have found that you
must be very careful to fully bond the PNP to the silver with a
Hot iron.

I use an iron and clean the silver with a scrubbie. I might not be
letting the paper bond onto the silver. I am alway afraid of keeping
on the heat too long.

Thanks for the info.

9

Suzanne,

I have found that after applying a hot iron, it is important to
immediately put the piece under cool (not necessarily cold) water.
Only then do I pull the PnP off. Works 98% of the time.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry!