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Plating over firescale & Worn out Prips

I have a bowel that I raised out of 12 inch disc of 18 gauge
sterling. It took longer to solder the base on than I expected and I
now have firescale. I would prefer not to sand it off, because I
will lose my plannishing marks. I have two questions:

  1. Can I silver plated over the firescale, or does the firescale have
    to be removed first for the silver to properly adhere? (I would use a
    commercial plating company)

  2. During the soldering which caused the firescale in the first
    place, could I have sprinkled powdered borax on the hot piece when I
    noticed that the Prips was wearing out?

Mitch Adams

Mitch:

You’ve stumbled on to one of those “ye olde ancient silversmith’s
tricks”: Nevermind the firestain, just plate over it. I’ve done it
myself on a couple of chalices, and it works just fine with no
special prep work beyond making sure the finishing is perfect.
(Somehow, plate seems to accentuate scratches you never knew were
there.) For a truly wild effect, have them do a gold wash on the
inside of the bowl. A bowl that large will just turn into a lake of
golden reflection. (The wash is very thin, so don’t do that except
for showpieces, or goblets.) I do it on my goblets when I can, the
effect is amazing.

Not to claim that I’m the slacker responsible for this little trick,
I picked it up at the Cass in London. It was pretty much SOP to
plate hollowware rather than worrying about the firestain.

As for borax and prips? Now that I think about it more, maybe it
would work…Couldn’t hurt anyway, except that doing that would
distract you from finishing the joint and ending the problem
altogether. Generally, if you’re burning out your flux, that’s a good
time to stop, take a deep breath while you’re waiting for the pickle,
and do it again carefully, rather than trying frantic 'off the cuff’
stunts while the metal’s hot, and the torch is waving around
randomly. You might want to ponder using white paste flux when doing
large things that are apt to take a while. It hangs around a lot
longer than Prips does. Much preferred (by me anyway) for
silversmithing scale work.

Regards,
Brian Meek.

You can easily do a depeltion plating by “raising the firescale” To
do this you heat the piece to an annealing temperture until it all
turns black. Let it air cool and pickel. It should now be white.
Repeat this again leaving it in the pickel a good long time, perhaps
10 to 20 minutes. It won’t get as black as you repeat the cycle. You
may repeat anywhere from 2 to 5 times depending on heat and strength
of your pickel. This process will remove the copper from the surface
and leave a very thin fine silver layer. Polish this with rouge and
it will look great. The downside is that there is still firescale
under the fine silver skin, so if you polish through it you will get
the effect of firescale again. Be sure that all the scratches are out
before you start because all you can do is a final polish at the end.

 You might want to ponder using white paste flux when doing large
things that are apt to take a while. It hangs around a *lot* longer
than Prips does. Much preferred (by me anyway) for silversmithing
scale work. 

Hi Brian,

I agree with everything you said, except for the flux part. I
personally prefer Prip’s or Battern’s over paste flux, and I think
they hold up at higher temperatures better. The best flux, though,
for high temperatures, is black flux. It’s very strange-looking,
though, so I mix it with white, and make gray flux. It also does a
superior job with copper and brass alloys. Black flux is the flux
you need if you want to silver solder stainless steel. (available at
welders suppliers, if you don’t see it in your favorite jewelry
supply catalog)

Warm regards,
Cindy
Cynthia Eid
http://www.cynthiaeid.com

Hi Cindy:

I use the dreaded Black Flux myself, but figured it was a little too
weird to bring up. Didn’t know you could mix it with the white
though.

Hummmm…

(Various ‘dark and light side of force’ jokes are now floating
through my head…) I’ve always had much better endurance with the
paste fluxes than with anything thin like prips. Although, come to
think of it, some of the people I teach with like to really water
the paste fluxes down. I tend to like it thick like kindergarten
paste. That may have a lot to do with it. (My logic is that I can
always water it down if I need to. Thickening takes more time than
I usually have.)

It suddenly occurred to me after my initial reply that I wasn’t
entirely sure what he was using the prips for. I initially assumed
as a joint flux, but the way he was writing, it seems like he was
using it as an ‘all over’ firecoat, sort of like ‘ye-olde’ boric
acid & alcohol.

If so, there are easier ways to skin that cat, boric acid and
alcohol being the classic, but argotect or ?stop-ox? being the two
others that come to mind.

Cheers-
Brian.

Black flux is just white flux with metallic boron added to it. So
diluting it with white just reduces the amount of boron available in
the flux. One thing to remember is not all white fluxes are the same
there are several “safer” white fluxes that don’t contain the
fluorides or the sodium hydroxide. These “safer” fluxes just don’t
work as good but they are somewhat less toxic to breathe. You should
have sufficient ventilation that this is not an issue so use the
more effective white fluxes like handy flux. They are much better
soldering fluxes than prips or batterns. When soldering silver items
I first coat the whole item with prips flux then apply the white
paste flux to the joint area then dry off the paste before applying
the solder.

Jim