Soldering potmetal
 

Greetings,
I had to repair my daughter's music box. Gilded potmetal. The hinge
comprises three brass tubes and a copper rod. One of the hinge tubes came
off. My Radio Shack soldering iron couldn't get the thing hot enough; the
box was too efficient a heat sink. I tried using a propane torch. I got a
cold joint, which broke again soon thereafter. So I cooked it a little
hotter, the joint drew the solder in...and then the box melted through.
Filled the hole with solder. When I glued the felt lining back in, the
pothole didn't show.

Then one of the legs broke off. I used epoxy this time...

So, when it breaks again: Any tips on how I can get a good solder joint
with my limited equipment? Or should I skip the solder and use epoxy?

Thanks.

--
"Keep your ass behind you"

Australopithecus scobis wrote in
e:

So, when it breaks again: Any tips on how I can get a good solder joint
with my limited equipment? Or should I skip the solder and use epoxy?


http://www.muggyweld.com/potmetal.html

On Thu, 09 Sep 2004 02:51:53 +0000, Murray Peterson wrote:



http://www.muggyweld.com/potmetal.html

Cool. Thanks.
--

Australopithecus scobis wrote:

On Thu, 09 Sep 2004 02:51:53 +0000, Murray Peterson wrote:


http://www.muggyweld.com/potmetal.html


Cool. Thanks.

Yea, that was cool.

--
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Being right is more powerfull than large corporations or governments.
The right argument may not be pervasive, but the facts eventually are.

Potmetal can be welded or soldered, but it's tricky.
There is a special solder available for potmetal. See
http://www.caswellplating.com/aids/solderit.htm

I've seen this material in a hobby store (Hub Hobbies in St. Paul, MN),
Caswell is by no means the only source.

The problem with potmetal is that it is extremely "hot short" as you
observed. The transition from solid to liquid is abrupt, and the liquid
state is very runny.
The solution is to constrain or "jig" the joint so when the metal melts it
has nowhere to go but where you want it to be. I've used clay, petrobond
casting sand, and a blue ceramic jigging putty from Eastwood. The jigging
putty works best, don't know if they still offer it or not.

"Australopithecus scobis" wrote in message
e...
Greetings,
I had to repair my daughter's music box. Gilded potmetal. The hinge
comprises three brass tubes and a copper rod. One of the hinge tubes came
off. My Radio Shack soldering iron couldn't get the thing hot enough; the
box was too efficient a heat sink. I tried using a propane torch. I got a
cold joint, which broke again soon thereafter. So I cooked it a little
hotter, the joint drew the solder in...and then the box melted through.
Filled the hole with solder. When I glued the felt lining back in, the
pothole didn't show.

Then one of the legs broke off. I used epoxy this time...

So, when it breaks again: Any tips on how I can get a good solder joint
with my limited equipment? Or should I skip the solder and use epoxy?

Thanks.

--
"Keep your ass behind you"

Hmmm ... having just bought some Cerrobend, it pops to mind. It has a
very low melting point (160F) and tensile strength about that of solder
(6k). The question is - will it wet pot metal? Probably not, or we'd
have heard about it. I may try it anyhow. Unless someone already has.
??

Bob