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Silver soldering and acids


#1

Dear Beginners as well as others,

I note that there has been some discussion about using various
pickles to clean the silver

I thought Orchid members might be interested to know that for
the past fifteen years I have been using Potassium Alum ( the
commercial grade as the pure grade is horribly expensive) It
costs approx Aud$17.00 for 2kg. (4.225lbs I think) I throw a
handful into about about 1 and half litres of water ( say 6 cups
of water) . The mixture does need to be heated… a medium heat
is all that is required to remove flux from the work. I also use
it to bring up fine silver when doing Keum Boo, or covering
firescale. Replace the mixture when it starts looking "dirty"
Alum is used in tanning leather. Any good chemical supplier
should have it in stock.

At least I no longer have any holes in my clothes.!!! Always a
bonus in this economic reationalism age.

Felicity in beautiful West Oz , where spring is just around the corner and
the first blowies arrived in 27degrees heat today!


#2

Had to add my tidbit of knowlege to Felicity’s post regarding
Potassium Alum…

When I set up a bench in my home, I had no place to put acid to
assure that my kids wouldn’t get into it… so I used Alum.
Regular old alum from the grocery store like one would use to
make… pickles. :c) Hence the name?

Okay… now I’m no longer lurking… but out from under
the bench… ;c) Enjoy this list a great deal… thanks all!

Maire
baking in TatorTown (aka Boise, Idaho)


#3
I note that there has been some discussion about using various
pickles to clean the silver

Alum is what I use to make dill pickles…wonder which came
first, the “pickle” as in vegetables preserved in acid, or the
"pickle" as the acid to clean metal…

Anyway, I use food-grade citric acid in a crock pot set on low.
I mix 8 oz. to 2 qt. of water. It is cheap and biodegradable,
unlike Sparex. The only two drawbacks that I have had is that
little spills or drips dry sticky, and that tiny flecks of fuzzy
grey mold now grow on the surface of my rinse basin if it is
undisturbed over the weekend. [Heaven knows my Sparex rinse
basin could never support life! Quite the opposite.]
Otherwise, it works as well as the more toxic stuff I used to
use. I bought mine from a baking/cooking supply house; sometimes
it is called “sour salt”. A half pound runs about $3 US. I know
the King Arthur Baker’s Supply Catalog in VT sells it. Anne
Hollerbach


#4

Hello everyone;

Alum is the standard pickle in Thai silver manufacturing. Called
"Sansorm" in the local language. It is cheap, effective and
highly safe to use. I use sulphuric acid only for very resistant
fire scales and ONLY with my personal supervision! safety always
comes first :slight_smile:

Hanuman

Dr. E. Aspler
aspler@ganoksin.com
Managing Director
Ganoksin Jewelry Co.,Ltd

Webmaster Ganoksin Online

ICQ # 864 5224


#5

Hello everyone,

if pickling with alum really works so well, why did nobody ever
tell me about it??? I’ve always been taught to pickle with
sulphuric acic, but I really hate it. Also in literature I did
find no hint on alum. So maybe there are any good reasons to keep
working with acid instead of alum?

And what about stones? If you’ve done a repair on a piece of
jewelry with the stones in place, is it possible to pickle the
piece in alum without damaging the stones?

Thanks,
Sabine

sabineas virtual gallery:
http://www.sabinea.com/


#6
   if pickling with alum really works so well, why did nobody
ever tell me about it??? I've always been taught to pickle with
sulphuric acic, but I really hate it. Also in literature I did
find no hint on alum. So maybe there are any good reasons to
keep working with acid instead of alum? 

Sure. Acid is faster. And a bit more effective. Alum will not
quite get the fire scale as effectively, especially on some gold
alloys. But then: what’s this about not believing it just cause
you can’t find it in print? Who’ever said the books are
complete? Hah! Most of em are the basics. Pickle is used cause
it’s long lasting and effective. (I assume you realize that
almost nobody actually uses sulphuric acid itself anymore as a
pickle for normal jewelry work. We all use Sodium bisulphite,
sold as sparex or other such. It’s a sulphuric acid salt, and is
much safer to use, while being almost as effective.)

Alum is gentler and safer yet, but not as effective. If it
works for you, great. But few professionals are in any hurry to
switch. On the other hand, many of those same professionals ALSO
have a beaker of alum solution sitting around for when we break a
drill bit off in the work. Ordinary pickle will dissolve the
bit, of course, but then makes a mess of other work as a result,
and especially the piece with the broken bit gets heavily copper
plated while the bit dissolves. With alum, you don’t get this
copper plating, and if you boil the solution, the broken bit is
quickly removed.

   And what about stones? If you've done a repair on a piece
of jewelry with the stones in place, is it possible to pickle
the piece in alum without damaging the stones? 

Alum is no more dangerous to the stones than is pickle. Any
stone which should not go in normal pickle should not go in the
alum either. Alum works for the same reason sparex pickle works.
It’s an acid salt. Some stones which should not go in pickle
are things like pearls, turqoise, malachite, amber, coral, jet,
lapis lazuli, peridot, and “soude’” type doublets (many of the
green spinel synthetics. The acid sometimes attacks the glue
bond between top and bottom pieces…) I wouldn’t put any of
these in alum either.

Hope this helps.

Peter Rowe


#7

Dear Peter, Alum works fine for removing bits of broken drill
bits, but I find that Hardware store variety Muriatic acid works
even faster! About half the time, and you can even shorten that
time by rattling the remains of the bit out in the ultrasonic.
Just another opinion, Eben Lenz


#8

Peter,

I did not say, that I’m not believing it! I was only
wondering…

Over here in Germany (almost) everybody does use sulphuric acid
itself for pickling. Never heard of Sodium bisulphite. But I
think I’ll try this out. And also the alum pickle. Well, that’s
what I am here for… getting to know different or new working
methods.

Thank you,
Sabine

sabineas virtual gallery:
http://www.sabinea.com/


#9

Since it’s come up about the toxicity of Sparex…does anyone
know how long you can use the same batch of Sparex and the safest
way to dispose of the Sparex when one can no longer use it?? I
like the idea about citric acid and will try that when I run out
of Sparex!

Thanks!
Cat Dancing
Enjoying life in the country between Austin and Houston, Texas


#10
   Dear Peter, Alum works fine for removing bits of broken
drill bits, but I find that Hardware store variety Muriatic
acid works even faster!  About half the time, and you can even
shorten that time by rattling the remains of the bit out in the
ultrasonic.  Just another opinion, 

You’re right. my only problem with the muriatic or HCL is that
fumes tend to rust every tool in the area.

Peter


#11
   Over here in Germany (almost) everybody does use sulphuric
acid itself for pickling. Never heard of Sodium bisulphite. But
I think I'll try this out. And also the alum pickle. Well,
that's what I am here for... getting to know different or new
working methods. 

Um … Actually, that was a typo. It’s sodium bisulphAte, not
ite. The stuff is available here as a product called Sparex.
but you can also find it as an acidifier used to lower the ph in
swimming pools. In that guise, it’s often a lot cheaper. At
least here, anyway. Germany, I don’t know about…

Peter


#12

G’day Sabinea et al, In the context of pickling silver and gold,
do NOT use sodium sulphite (ITE) but DO use sodium bisulphate
(ATE) which is also sodium hydrogen sulphate, and also sodium
acid sulphate. NaHSO4

Sodium sulphite is excellent for disinfecting vessels and other
equipment when making home-brew. I use it all the time. But
then, I make a delicious home-brew :wink: Cheers,

       / \
     /  /
   /  /                                
 /  /__| \      @John_Burgess2
(______ )       

At sunny Nelson NZ in early spring with lambs, daffs, magnolias.
kowhai,
Cold starry nights, cold sunny days (well, quite often)


#13

Dear Peter, Not to be a wise-ass, but that’s why I always use a
stoppered container, usually one with a plastic lid and a glass
body.Only a minor amount of fumes seems to escape. I haven’t
noticed any appreciable rust forming for the 15-odd seconds that
the jar is open to retrieve the “soaking” item.
another two cents, Eben


#14

I stopped using Sparex a long time ago when I discovered a
product called E-Z Clor used in swimming pools. It’s 96% sodium
bisulphate and comes in a gallon and a half container. It’s a lot
cheaper than Sparex. You can buy it from a pool supply.


#15
   Since it's come up about the toxicity of Sparex.....does
anyone know how long you can use the same batch of Sparex 

Use it till it stops adaquately dissolving the flux and oxides,
or is so saturated with copper that you have a hard time keeping
it from plating out with copper, or until the pickle pot is so
grungy looking that you can’t stand it anymore and just HAVE to
clean the sucker out.

  and the safest way to dispose of the Sparex when one can no
longer use it?? 

dilute it with ordinary water and flush it if you’re connected
to a municipal sewer. Small amounts are not going to harm
anything at all in the environment. In a small closed system like
a septic tank, you might slow down the tank process, so that’s
not a good place to put it. If you’re worried, though, you
could always just let the pot boil dry, scrape the solids into
whatever’s handy, and take it to whatever local facility handles
out of the ordinary waste materials. For what it’s worth, some
types of hardware store drain cleaner are often a dilute
sulphuric acid. This is no worse, though as a depleted salt,
less effective as a drain cleaner. About the only concern might
be the small amount of dissolved copper, and you’re putting into
the environment with your pickle, a lot less copper than in a
single penny dropped in the river… About all it might do is
briefly slow down the amount of algae growing in your sewer
lines… while large users of the stuff need to be more
careful, we’re not generally talking about a polluting or toxic
waste here. Just a mild acid compound that’s already common and
naturally occurring in the environment, and which will cause your
city sewage disposal system no harm or problem in the small
amounts invovled here.

Peter Rowe


#16
    Since it's come up about the toxicity of Sparex.....does
anyone know how long you can use the same batch of Sparex and
the safest way to dispose of the Sparex when one can no longer
use it?? I like the idea about citric acid and will try that
when I run out of Sparex!  

I use Sparex until it turns a funny color (Usually a dark
greenish blue.) Then, I dump it into a kitty litter box (the
kitty went to kitty heaven a few years ago,) and let the liquid
evaporate. Then, every once in a while, I scrape the dried stuff
into a plastic bag and throw it away. Although, if it is useable
in Swimming Pools as an acid, I doubt that it is very toxic in
water . . . one could dump it down the drain without too much
worry?


#17

Neutralize it with baking soda…adding a little at a time until
it is absorbed. If you add too much, it will bubble over. Once
you’ve added as much baking soda as you can…you have two
choices. You can bag it and throw it away or pour it down the
sink, with the water on (hot, I think) and pouring more soda down
as you go. Run the water for a bit. This may anger some people,
but throwing it into the solid waste stream is probably better
and less costly overall.

If it’s poured down the sink, the water treatment plant has to
filter that out. Another option is to nuetralize it with the
soda and then let it evaporate before throwing out.
Unfortunately, who has a safe place to leave pickle out as it
evaporates?

My 2 cents.
Elaine, Illinois, USA


#18
       [snip]  that's why I always use a stoppered container,
usually one with a plastic lid and a glass body.Only a minor
amount of fumes seems to escape.  I haven't noticed any
appreciable rust forming for the 15-odd seconds that the jar is
open to retrieve the "soaking" item. 

So you’re taking the drill bits out by just soaking them cold in
muriatic? When I’ve tried that, it seemed to take forever… I
was talking about using it hot, just below boiling. Plastic lids
don’t seem to stop the fumes then… THEN it’s fast, Buuttt…
So I use Alum, and I use it at a rapid boil. Besides, our shop
is across the street from a drug store, where I can pick up a
little spice jar of alum if I happen to be out. They don’t have
muriatic/HCL. And, er. Well, I don’t seem to have your stopperd
containers so handy as one or another of those old beakers
sitting by the sink which don’t seem to have lids. Remember that
normally when those drills break, I’m in a hurry, and just want
to stick the ring in a beaker, put it on the hot plate, and be
able to come back in a half hour and get on with the job…

Peter


#19
       Since it's come up about the toxicity of
Sparex.....does anyone know how long you can use the same batch
of Sparex 

G’day; Don’t let’s be miserly when using Sparex; it’s so cheap
to buy it as pool pH adjuster that you could easily afford to use
a fresh batch every day; what; about 2c a pot? In any case if you
don’t want to ‘waste’ you might use the appearance of a pale blue
colour in your pickle pot (the presence of copper sulphate) as
an indication that it is about time to make up a fresh batch.
Cheers,

       / \
     /  /
   /  /                                
 /  /__| \      @John_Burgess2
(______ )       

Mapua village is beautiful in spring. Which has thoroughly sprung.


#20
    Although, if it is useable in Swimming Pools as an acid, I
doubt that it is very toxic in water . . . one could dump it
down the drain without too much worry? 

Being overly cautious in general, and slightly paranoid about
the way people can twist things they read on the internet, I
couldn’t let this pass without comment.

Umm…not that I’m saying Sparex is anywhere near the bogey that
bombing gold is, but “useable in Swimming Pools” isn’t really a
great dividing line for chemical safety. Chlorine goes in
swimming pools as well, but excessive chlorine (actually,
leakage of chlorine (?)) caused a swimming pool full of people to
have to go to the hospital this summer in San Diego County… For
example, HCl diluted, can be sold as “muriatic acid” and is
relatively safe, HCl in high concentration is another matter
altogether.

Use any chemical with caution, please, and if you’re in the
U.S., read the MSDS (MDSS? Material Safety Data Sheet) and keep
it on hand…

Better safe than sorry, and ignorance won’t keep any of us from
suffering the consequences.

This is NOT directed at original writer of this message, and
they have received a note to that effect in private.