Chinese White

At the suggestion of an Orchid writer, I wanted to try Chinese White
watercolor as a solder resist. This product is offered in jewelry
catalogs in block form as Winsor & Newton Artists’ Chinese White.
The same is available in tubes at art stores. Beware that Winsor &
Newton also sells a less expensive look-alike “Cotman” Chinese White
watercolor that contains lead. The lead content is revealed in very
small print on the tiny 5 ml tube, and, likely would contaminate
your metal and you if used as a solder resist. Nancy www.psi-
design.com

Dear Nancy, all these various permutations and combinations of white
paint as a solder resist seems to have obscured the traditional
practice amongst older working jewellers of simply mixing a little
polishing rouge powder into a little light oil to make up a thin
paste. This would be painted precisely over the solder area to be
protected. In early stages of heating the mixture bubbles and smokes
a little but quickly settles down to form a resistant area. After
fifty years of designing and hand-crafting I still use this method
that I was taught as an apprentice.

I’m a little balder now than I used to be, but apart from that I
haven’t experienced any discernible ill effects. Sometimes the old
ways of doing things are there for the simple reason that they are
tried and tested by generations of experienced craftspeople. They
simply work. I hasten to add that I love my modern technologies,
but… Kind regards and best wishes to all for the Season, Rex

    the traditional practice amongst older working jewellers of
simply mixing a little polishing rouge powder into a little light
oil to make up a thin paste. This would be painted precisely over
the solder area to be protected. In early stages of heating the
mixture bubbles and  smokes a little but quickly settles down to
form a resistant area. 

Rex, my question is: do you then put your item in pickle after
soldering or does the iron oxide contaminate it?

Annette

Annette, You quench in water, then wash it (a little ammonia and soap
never hurts) and brush it to remove as much of the rouge as possible
before pickling.

Also, if you don’t want to use light oil, use lighter fluid as a
diluent for the rouge. Works beautifully and doesn’t create the
"scene" you might think, because it evaporates quickly. You can use
a little lighter fluid OR some ammonia and soap after soldering and
before pickling to clean up the rouge.

It works beautifully and seems more tolerant of higher temps than
whiteout or yellow ochre.

Karen Goeller
@Karen_Goeller

Hi Annette, good question about whether the iron oxide in the rouge
and oil mix affects pickling-out after soldering. I’ve honestly never
thought of that aspect, and I’ve merrily pickled away without either
myself or the pickle being affected to any discernible degree.

Now that you’ve raised the concept I hope my pickle doesn’t wake up
to the idea and start turning everything pink. Admittedly I’ve only
ever used the mix very specifically - and consequently only in very
small amounts. Perhaps if one smothered the work in the rouge-oil mix
it might be a different matter?

Thank you for making me think. All the best for the Season,

Rex