Powder Flask Repair

[CARBABY]

Soldering a powder flask. I have become the owner of
a replica powder flask that has separated on the solder
join/seam. Any guidance would be appreciated.
- What is the best method to rejoin?
- What percent tin to lead should be used?
- What flux?
- Can a propane torch with the supplied stock copper
soldering head be implemented or a direct
flame be used? Or does one attack this with an old
copper solder head with a blow torch.
- CAVEAT: Last weekend on the TV - PBS Channel,
Roy Underhill on the WoodWright's Shop
hosted a Tin Smith. The Tin-Smith demonstrated
how Tin-ware was joined by soldering. The
methodology was with an old hot copper head
soldering iron. The tin was fluxed, the iron was
taken from the heat source moved to the solder
and then touched to the "fluxed area" and the
solder ran/(wicked) from the iron to the intended
area.
The concerns with this method: The soldering
will be on joining two edges of the flask (not an
overlapping joint ~rather a butt joint - the thickness
of the flask metal) so will there be slop of solder
metal on the out side of the flask, making removal
a problem. Also once the heat (iron) is applied will
the area of the already soldered joint come apart
and I will have be chasing another open
seam.
- Other FYIs
- The flask shell looks like a mixture copper
or brass. (It is not Zinc.)
- Flask has never been used. No powder in
the flask and no residue.

 

[bdarin]

Sounds like a simple enough soldering job. The flask being copper based it will take solder real easily. We used to get Roy Underhill in this market on PBS ch. 17 (WNED, Buffalo) but they canned him a couple of years ago and replaced him with Motor Week. Anyway, Ol' Roy had no power tools at all....everything was done with hand tools. Soldering with one of those antiques takes practice...kind of like ironing with one of those old irons that had to go on the stove to get hot: either too hot or too cool, just right for only a few minutes. If I were doing this, I'd use an ordinary electric soldering iron and regular old radio solder (60/40 with tin and flux built in). It should go really easy. I used to repair old brass model airplane fuel tanks like that. I think I once repaired a set of brass carburetor floats this way back in the 70's. Everything worked fine. :thumbsup: