Subject: Silver Solder with cadmium

From: [email-masked] (Paul Boulle)
Date: Thu, 26 Sep 1996 19:31:09

I picked up some silver solder rods cheaply from a second has shop. The rods 
are marked as L_Ag30Cd (DIN 8513). Can anyone tell me what there intended use 
is and why they contain cadmium?

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From: [email-masked] (Ernie Leimkuhler)
Date: 27 Sep 1996 07:54:34 GMT

> is and why they contain cadmium?

I'm not sure what that alloy is for.
The only Cadmium silver-solder I've ever used was some wonderful stuff
>from  Indian Jewelry supply. 
It was kind of yellow and was designed to blend into brass and bronze.
Toxic as all hell, but beautiful solder.

Best of luck

-- 
*********************************************************************
                            Ernie Leimkuhler
                   STAGESMITH PRODUCTIONS
                     Custom Metal Fabrication
       ABANA       AWS        SCA        IATSE Local 15/488
                        Renton, Washington, USA
*********************************************************************

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From: [email-masked]
Date: 27 Sep 1996 14:16:32 GMT

>is and why they contain cadmium?

One of the functions of cadmium in silver solder is to improve the solder's
flow characteristics.    Once the solder becomes fluid (hot enough)
it will find and flow into the tiniest crack.

A former co-worker described the process where liners were silver
soldered into large gun barrels during WWII - the barrels were bored 
to size, and the liners basically pressed in.  Then large torches
brought the entire assembly up to temperature, and then silver
solder was applied to one end.  

The workers could tell when the joint was good, because a ring of
silver solder would appear at the other end of the barrel, many feet
away.

The *other* notable function of cadmium is to be very, very toxic.
The fumes from the molten solder pool are cadmium rich, and 
this element has been proven to cause all kinds of damage
to humans, both long- and short-term.

So if you insist on using cad-bearing solder, use plenty of ventilation,
and do *not* stick your face close in to the joint as the solder 
begins to flow.  (aside from the flux fumes, too!)

===========================================================

 1959 BMW R50                                           Jim Rozen              
 1969 BMW R60US                                (JRR0 @ watson.ibm.com)                 
 1975 BMW R75/6    (The "new" one)        

===========================================================

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From: [email-masked] (Rich Klopp)
Date: 27 Sep 1996 15:28:29 GMT

I don't know whether what you have is equivalent to Easy Flow 45, but the
cadmium is there simply to make an alloy with desired melting and flow
characteristics.

Easy Flow 45 was one well known brand of the formerly popular
cadmium-containing 45% silver solders. It was a wonderfully fluid solder
with relatively low melting temperature (1100 deg F or so) and very narrow
melting range. The fluidity, low temperature, and narrow range came about
because the silver and cadmium were in the corrent portion to form a
"eutectic" alloy. It's too bad Easy Flow 45 has gone away, because there's
no substitute quite as nice to work with (at least until the cadmium gets
you!). The 56% and 72% alloys are pretty nice but melt at higher
temperature and cost more. The non-cadmium 45% alloys have wider melting
range and can therefore separate on repeated heating or accidental
overheating.

-- 
Rich Klopp