I understand that lead solder will form a eutectic mixture with
silver and “eat away” the silver. Does the same thing happen with
tin/silver solder and sterling? If so, at what temperature does this
happen?
Milt
Calgary, Canada
I understand that lead solder will form a eutectic mixture with silver and "eat away" the silver. Does the same thing happen with tin/silver solder and sterling? If so, at what temperature does this happen?
221C @ 96.5% tin, balance silver. The reason tin or lead eats into
the metal is not the eutectic but that it has such a low melting
point and it will easily alloy into the silver. Tin makes silver
brittle so don’t use it on highly stressed parts.
James Binnion
James Binnion Metal Arts
cheap solder wastes your metal- the pickle can attack it and it’s
intended for plumbing more than jewellery making- I presume you are
talking about the 2% silver bearing solders sold in home stores and
radio shacks- definitely not for jewellery construction. won’t hold
up over time either. Buy good hard silver solder or make your own
with zinc not tin, and definitely not with lead-it’s illegal in
jewellery these days anyway… rer
RER. Thanks for your response, I should clarify that I am doing a
repair on a nickel plated sterling ceremonial object. I can not hard
solder it. I am trying to decide between rivets, screws and soft
solder. I am also trying to better understand the properties of soft
solders and their appropriate applications with sterling silver.
Regards
Milt
cheap solder wastes your metal- the pickle can attack it and it's intended for plumbing more than jewellery making
There is another problem with tin solder, tin, like antimony and
bismuth (submetallic elements) expand upon cooling wheras metals
contract. This means that over time tin soldered joints will fail by
pushing themselves apart. In electrical circuitly this is commonly
known as “dry joints” which have lost their conductivity as the
solder detaches from the circuit and oxidises. So, even a tin/silver
alloy that is of assayable quality wouldnt last the test of time.
Ever noyice that your tooth fillings really ache in cold weather?
that is the tin/silver alloy giving you problems, not just the cold.
Nick Royall
I should clarify that I am doing a repair on a nickel plated sterling ceremonial object. I can not hard solder it. I am trying to decide between rivets, screws and soft solder. I am also trying to better understand the properties of soft solders and their appropriate applications with sterling silver.
On manufactured teapots, etc., handles and bases are routinely
applied with soft solders. I worked in a repair shop in Chicago which
took in repairs from jewelry and department stores such as Marshall
Field’s, and I worked on these types of objects. After soft soldering
and cleaning off the joints as well as possible, everything went into
the plating room for a complete re-plating, which hid the solder
seams.
M’lou Brubaker
Minnesota, USA
Why can’t you hard solder it? Is it already lead soldered together?
If the nickle plating is an issue send it to a good plater and have
it stripped off first.
Before I was a gold and platinum smith, I used to be a liturgical
silversmith and did a LOT of silver hollow ware and flat ware repair
and re plating. Still do a bit on old and rare pieces because most
folks won’t touch it. The most recent piece I repaired was a pair of
over 200 year old silver drinking cups that were badly repaired with
glue, foil, and yes paper clips. No pressure:-) When I repaired silver
plated goods, yes I would use soft solder because the feet, finials,
handles and spouts were cast out of low temp pot metal.
I used Tix solder and then silver plate it afterwards.
On sterling silver. NEVER. I had a chalice that I made nearly
destroyed by a hack repair man who lead soldered on it after it was
dropped and part was broken off. I had to disassemble the whole
thing, scrape the lead solder off, then reassemble with silver
solder.
Once a piece of silver or gold is lead soldered you can never go
back and use higher temp solder on it unless it is completely
decontaminated. It likes to alloy /eat into the silver or gold. It is
a much weaker bond than hard solder as well.
Lead soldering on precious metals is akin to gluing stones in place.
It must be avoided at all costs.
I’d like to hear from Jeffrey Herman on this. He is the REAL expert
on silver restoration.
Have fun and make lots of Jewelry.
Jo Haemer
timothywgreen.com
In a previous job when I was asked to recommend a soft solder for
use on sterling silver we would always go for a 4% silver 96% tin
alloy which has a melting point of about 221C (490F). As a rough
rule of thumb a soft soldered joint has a bout a quarter of the
strength of a soldered (brazed) joint. For some reason I have a
memory of this solder being used by one manufacturer for sticking
the spouts on to teapots and coffee pots!
Charles Allenden
Hi Jo,
Sounds like you’re a pro at restoration!
I’ve never had a rhodium plated piece in the shop for repair. If I
did, I’d remove the rhodium and/or nickel to get down to the base
alloy. Not doing so would be like soldering on top of firestain which
would produce a weak join.
Unfortunately, I’m not a big fan of Tix. It’s very brittle and the
flow quality is less than desirable. It’s akin to using a
cyanoacrylate - poor shear strength. Sorry Jo. So, when working with
white metal, I tend to go with plain ol’ tin/lead solder, drawing it
down to approx…020" and using short lengths as opposed to stick
soldering. If I do get a bit of solder on the plated piece I’m
working on, I’ll use a sharp burnisher (not a scraper) to remove it.
Or, I’ll gently heat that area and remove it with a Q-tip.
Then I’ll use Wright’s silver polish on a Q-tip and gently remove
any remaining residue. (Shhhhhhh, that’s a trade secret!). Since I
don’t do any plating, I make my customers aware that I will be doing
a STRUCTURAL REPAIR, and they may see a very thin solder line where
the white metal piece was reattached. There have been times that a
previous repair revealed the base metal, so after I re-repaired the
piece I’ll send the piece to my plater, should my customer desire.
The very rare occasions I will use tin/silver solder is if I
absolutely cannot identify if every last bit of lead solder had been
removed. It sometimes depends on the piece I’m working on. If I can
use my pulse arc welder, I go that route to maintain the integrity of
the object. For even if there’s lead hiding, the welding is so
localized that it won’t’ flow the lead. And Jo’s absolutely correct -
the high temperature when melting hard silver solder will of course
melt the lead, allowing it to eat into the silver like the Ebola
virus, creating its own alloy. I learned this lesson very early :~/
I hope this helps.
Jeff Herman
This item has already been repaired with some typeof soft solder so I
can not use hard solder on it. I am currently using a combination of
Staybrite and rivets/screws to repair it. Also, I did discuss the
repair with both Jeffery Herman and Jennifer Friedman before
starting.
Regards
Milt Fischbein
Jeff -What combo of tin to lead in the solder do you use? I used to
buy 50/50 but have a hard time finding it any more. That’s why I
went to Tix.
I’ve used the old Wrights trick many times too. I also find that a
stiff bristle brush with Tripoli will remove extra soft solder as
well but will go through a plated surface. I plate after.
I like to roll out all of my solders paper thin so that I can handle
larger pallions that melt into tiny amounts. I actually do this for
all of my solders, gold, silver etc. It saves money and makes for
tidier seams. It’s especially handy when making or repairing chains.
Have fun and make lots of jewelry.
Jo Haemer
timothywgreen.com
Jo,
I use 63 tin/37 lead soft solder wire that’s eutectic and melts at
361 degrees F. I couple it with Superior #30 Soft Soldering Flux. I
use some 0000 steel wool to clean the solder before using it.
If I find the residual lead to be a bit stubborn when removing it, I
may use a piece of moistened hard felt with Wright’s.
Jeff Herman
I read the topic correctly this time. in my previous post when I
said, “regardless of what I’m repairing”, I mean pewter, brass,
copper, iron, and plated base metals; NOT silver or gold!
Using tin solder on sterling silver totally devalues the whole item.
Perhaps OK for fashion jewellery and tiny things where the weight of
silver is so little it may be cheaper to use silver rather than base
metal+plating, but you would not be able to stamp the item as
stirling silver if it has tin solder on it.
Alastair
Hi M’lou, soft solders have similar properties. In the order of
melting temps. Pure tin has the highest melting temperature of the
soft solders, is non toxic, and can be applied with a HOT soldering
iron. Then there are a range of tin/silver and tin/copper alloys
known as ‘lead free’, then tin/lead alloys, and lastly lead/bismuth
alloys that can melt in boiling water!
The fluxes are similar too. Resin flux for electrical stuff that
cannot stand a wash and rinse. Active flux (zinc chloride) for
anything that can be washed and nutralized afterwards; and
glycerine/hcl flux for the ultra-low temp solders.
I only use pure tin or ‘lead free’ regardless of what is being
repaired. This includes old lead/tin pewterware. Making my own
soldering irons with various copper bits is a big help, they are all
heated in a gas flame for speed and precision. Sometimes, when
repairing a silver plated EPNS item, I have to heat the whole area
to get a good meniscus in the soldered joint. Pure tin or ‘lead
free’ matches the silver plating and won’t discolour in time. (Clean
up with a fine brass brush, polish by hand with a silver cloth).
People fear lead like it’s radio active, and lead oxidises to a grey
colour. more lead = deeper grey.
Alastair
Jeffrey Herman…You’ve got my attention. To remove lead or
tin solder you mentioned "I’ll gently heat that area and remove it
with a Q-tip."What’s the trick…If you’re at the temperature to
melt low temp solder howdo you keep the Q-tip from burning? Is it
wet? Does it matter if it burns?
This item has already been repaired with some type of soft solder so I can not use hard solder on it.
This is not necessarily a recommendation for this job, but just a
related tip for those who don’t know (I hope I’m not repeating
something as I was not following this thread). When you get a piece
that someone has used lead-like soft solder on and you want to
remove it so you can use the proper high temperature solder to make
a stronger, undetectable repair. You can usually just soak the piece
in Muriatic Acid overnight (in a well ventilated area). The next
morning the offending solder will be crusty and come right off.
Karla,
I don’t let the Q-tip get anywhere near the flame. You have to be
quick. Use the smallest flame you can, gently heat the area (don’t
use any flux), remove the flame, and come in quick with the Q-tip. If
it burns a little, don’t worry - toss it in some water and use a
clean Q-tip. Don’t keep wiping with the same one or you’ll end up
depositing the lead right back on the piece. Water on the Q-tip will
only cool the solder.
Jeff Herman