On 1 Jan 2006 12:37:05 -0800, "mj" wrote:

I'm doing some brass model building and the book that I am using as a
guide (by Gerald Wingrove) mentions hard and soft solder. What am I
looking for as far as differences? I suspect the "hard" solder has a
higher melting point (silver solder???) than the soft solder.

Right.

The stuff that I got at Radio Shack has this on the label:

Standard Rosin-Core Solder
60/40 (does this mean 60% lead/40% tin?)

No: 60 tin, 40 lead.

I suppose that this is more a "soft" solder. What specs should I look
for in a "hard" solder.

Higher silver content will wet and flow better. In a cadmium-free
alloy I'd go with at least 45% silver and preferably 56%. I like
and use cadmium-bearing alloys because they work better, and I'm
careful about fumes. My go-to for nearly all silverbrazing is Harman
Handy Easyflo 45 or something very similar. A lot of
framebuilders (bicycles) use that material.

For fine work, Brownells offers some .030 wire and thin shimstock in
a cad-free 56% silversolder that works well but it won't color match
brass well.

A middle ground is a tin-silver solder like Harris Staybrite. 96 tin
4 silver. It's technically a soft solder, melts a bit higher than
tin/lead, but it's much stronger and wets brass beautifully. It's not
as strong as a "hard" silversolder, but strong enough for many
purposes. Also easier to use. You'll have more cleanup with a hard
solder because of the higher heat (1250 to 1400 deg F) and flux.

Jewellers use silversolders varying in melting temp from "hard" to
"easy" so they can make progressive joints. They start with hard,
then go to medium so they don't melt the previous joint, and so on.
A jeweller's supply place will have those materials.