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Firestain removal tips


#1

HI all,

If anyone has any tips on how to remove firestain, I would be glad to
hear them. I know that plating is an option, this is one I don’t
particularly want to use as it is an added cost. I have read about
concentrated acid solutions to strip the top layer of silver off,
thereby removing the firestain. I know people will say use Argentium
silver. We can’t get it yet in the UK except by shipping it in from
the US.

Thoughts and suggestions would be welcome.
Richard Whitehouse
www.richard-whitehouse.co.uk


#2

Richard,

Firescale isn’t fun, but it has to go. I file, then sand and when I
can barely see it, I polish with tripoli. Then I look again to see
if it is there, then I sand some more, then polish with tripoli. I
do this until I don’t see it, then I finish polishing.

The real trick is to try to not get it and there are several
products of flux out there to help. I use Cupronil ( spray) (Rio
Grande), blue gas flux (liquid (and I dip or brush on large pieces),
and there is Pripps flux. There is a recipe for it here somewhere on
Orchid. If it doesn’t show up again, I will find it for you.

jennifer friedman
http://www.jenniferfriedmanstudio.com


#3

This isn’t a firestain removal tip, but when I first started
learning to make jewelry, one of my teachers told me to get a supply
of white index cards to keep on my bench. When I finished soldering a
piece and had pickled it, I was told to stand it on the white card
and I should be able to see immediately if I had firescale on the
silver. It works like a charm and is easily seen. Quick way to check
to be sure it is gone, as well.

Kay


#4

When I was at college they taught us that firescale was something
that could be controlled by controlling the flame you are using and
paying close attention to you piece and the various colour changes
that occur. The takes a lot of concerntration, but well worth the
time and effort to concertrate when heating your piece.

Yes there are several fluxes out there that will help you lessen the
amount of firescale on your piece, and I certainly encourage you to
try them, but to master the control of your flame is the best and
most satifactory way of getting rid of fire scale, especially if you
are working with a piece of jewellery that does not have a lot of
metal to file and sand, ie: if your piece is narrow or of fine
detail.

My advise is to keep your flame small and reducing( well shaped but
not sharp) and watch carefully as the silver turns colour. Add as
much flux as you can without having it get stuck in places that will
be hard to clean, but silver should not go beyond a point of a dull
cherry red. I suggest that when soldering or heating, turn your
lights off in the workshop, the dull cherry red colour will glow from
beneath the surface, dont let it get to a point that you can see it
glow bright red like steel does. you are certain to get firescale at
that bright red tempreture.

Hope this helps. I have had a lot of problems with firescale in my
college years but have praticed hard to concerntrate on the colour of
the silver when heating.

Take care
Raakhi


#5

I never* get firescale. I use Rio Grande’s Stop-Ox. I wouldn’t dream
of working without it. Once you’ve got it, some say to depletion
silver. I do that when I don’t have firescale just to make the piece
bright white and prevent such rapid tarnishing, but I’ve not used it
for covering up firescale. Before I started using Stop-Ox, I just
kept after the stain with my regular polishing methods until it was
gone. It seemed it took forever.

*Once when metal on earrings was quite thin I got it.

Sue
http://www.jseenameljewelry.com


#6

Richard,

Just hate that ugly purple stain pushing up! Hate going back to 400
grit sandpaper time after time.

I find a soft goats hair brush liberally loaded with Tripoli on the
pendant motor does the best job for small pieces. (As my teacher
reminded me, it’s the Tripoli that does the cutting, not the brush
itself, so reload with Tripoli frequently. Work lightly from the
outside of the stain towards the centre. Move the direction of the
brush strokes around so you don’t groove a dent in the surface.
Trouble is, it all takes time. and time’s money. I’ll follow other
replies to your post with interest!

Jane Walker


#7
When I was at college they taught us that firescale was something
that could be controlled by controlling the flame you are using 

I think Richard was really looking for a magic bullet, like the old
nitric acid dip which actually attacks the silver faster than the
firescale (sounded good at the time, I guess). Alas, I have never
heard of anything effective besides just scouring it away in various
ways. Along the lines of the quote above, though, is to do all your
heating and soldering first - solder your earring post on the raw
casting and THEN finish the casting - stuff like that. But that and
the fluxes that actually work apparently and stuff don’t answer
Richard’s question as I understood it, “I’ve got it, now what can I
do about it?” Scrub, scrub, scrub, as far as I’ve ever found.

http://www.donivanandmaggiora.com


#8

Here is the recipe for pripps flux:

Prips Flux
64 grams/41 dwts. Borax
64 grams/41 dwts. Trisodium Phosphate
96 grams/61.5 dwts. Boric Acid Powder

Make a paste with a little distilled water and gradually add one
quart distilled water while heating. Bring this to a boil. This will
make a clear flux that protects against firecoat and is also an
excellent flux for gold and silver.

Jennifer Friedman

Ventura, CA where we finally had some rain last night, it came down
hard enough to hear it. I know that doesn’t mean much to most of you,
but here in southern CA we haven’t had more than 1 min of light rain
in 2 years.


#9
I do that when I don't have firescale just to make the piece bright
white and prevent such rapid tarnishing, but I've not used it for
covering up firescale... 

Even though it is appealing to have a layer of fine silver, I have
been under the impression that depletion gilding on traditional
Sterling silver causes firescale just beneath the fine silver
layer.? Is this true or not true?

Nancy
www.psi-design.com


#10
Even though it is appealing to have a layer of fine silver, I have
been under the impression that depletion gilding on traditional
Sterling silver causes firescale just beneath the fine silver
layer.? Is this true or not true? 

Yes it does. When you depletion guild you are dissolving the copper
oxide from the surface metal. To get the copper to oxidize you need
to heat it in the presence of oxygen and thus are creating
firestain. By dissolving the copper oxide you leave behind the fine
silver but just underneath it is the firestained silver that the acid
could not reach.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#11

Hi all,

As I thought, there is obviously no magic bullet to prevent firestain
after soldering. There is a chemical stripping recipe in Oppi
Untracht’s Jewellery book, perhaps I will try that. Thanks to all for
tips and on the subject.

Richard