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Removing soft solder


#1

Dear all, at the Department of Conservation / Restoration of the
Royal Academy of Antwerp, Belgium, we are setting up a series of
tests and analyses to determine the best ways of removing soft
solders from jewellery. This will be described in a dissertation,
one of the students makes. We would appreciate it if we could
receive practical about various ways of removing soft
solder, chemicals, succesfull ways, disasters etc. and references in
modern or older literature. When the study is finished, we will put
the outcome on this list. Many thanks, Patrick Storme.

Royal Academy of Fine Arts
Department of Conservation / Restoration of Metals
Blindestraat 9-13
B-2000 Antwerp
Belgium


#2

Hello Patrick,

For soft solder like an alloy of Tin (Sn) and lead (Pb), I use FeCl
(Ferrous Chloride) on gold and gold alloy. in a high concentration.

If you are lucky and there has been no overheating when the soft
solder was used. It will come of clean. If the gold is heated above
250 Degrees Celsius the lead out of the solder alloy will amalgate
with the gold. Like Mercury does at room temperature. If you are using
the FeCl you will see that the amalgatet gold is eaten away to

Greetings
Martin Niemeijer


#3

Patrick,

Just today I was reading in Tim McCreight’s book “The Complete
Metalsmith” and I quote from his book page 71.

“…soft solder can be chemically removed. Mix 3 oz. glacial acetic
acid with 1 oz. hydrogen peroxide. Heat, but do not boil. Brush onto
the affected area and allow several days to work. Tin will be left as
a white powder that can be brushed off.”

Not sure what this formula will do to any lead, cadmium or other
metals found in various grades of old or current soft solders


#4

Get some Muriatic acid from any hardware store. Plop the piece in A
PLASTIC container, and after about a day depending on how much soft
solder there is, the lead should be gone. Careful of the stones -
same rules apply as if you were using pickle acid. No need to heat
it. You can if you like. If you want to try to speed things up, put
the piece in a small PLASTIC container with a tight fitting lid and
float it in your ultrasonic for a while. That’s what works for me.


#5

Dear all, at the Department of Conservation / Restoration of the
Royal Academy of Antwerp, Belgium, we are setting up a series of
tests and analyses to determine the best ways of removing soft
solders from jewellery. This will be described in a dissertation,
one of the students makes. We would appreciate it if we could
receive practical about various ways of removing soft
solder, chemicals, succesfull ways, disasters etc. and references in
modern or older literature. This question appeared already on this
list some weeks ago, but only very few reactions were received and I
cannot imagine there is no more practical from all the
colleagues available. We really would like to have as many help as
possible, to make the study more overall interesting. When the
study is finished, we will put the outcome on this list. Many thanks,
Patrick Storme.


#6
   Dear all,  we are setting up a series of tests and analyses to
determine the best ways of removing soft solders from jewellery.  

G’day Patrick Storme. I have never had to remove soft solder
(which is usually lead and tin) from precious metals, but I would
suggest that as lead acetate is soluble in water, the jewellery
might be heated with around 25% acetic acid, which might dissolve
the lead and tin - after removing any acid susceptible stones first.
I have heard that hydrochloric acid might do the job, but as lead
chloride is quite insoluble, I rather doubt it - although some of
the tin may dissolve.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#7

Hi, On occasion we have customers who send us castings that have
parts soldered on with lowmelt lead solder. This type of solder will
usually melt in a vulcanizer ( not good) so what we have done when
we see this potential problem is this… We put it in our smallest
pickle pot with sparex /water and heat it to about 150 oF and leave
it in the pickle until the finding falls off and the solder
completely disintegrates off of the silver or gold item. Afterwards ,
there is usually a very tiny grey area that can be wiped off with
fine emery paper. If the pickle is still good, we will keep it in
a glass jar for other similar situations.

Hope this is helpful.

Daniel Grandi, www.racecarjewelry.com We do casting finishing and a
whole lot more for designers, stores and people in the trade. Contact
us at sales@racecarjewelry.com Or call 401-461-7803


#8

Hello ,

Provided the metals have not been exposed to such heat that would
cause the soft solder to amalgamate with the precious metal , you
can remove the soft solder mechanically . Using scrapers , files ,
abrasive media , one removes all visible solder . Then one heats
the piece gently , any missed soft solder will become shiney ,
easily observed , and is then removed as suggested above , the
process is repeated as necissary . I use this process frquently , and
carefully so as to not breath any lead dust , for simple lead solder
removal…

Mark Clodius