[Both the types Paul mentions in his reply below are actually variants of
soft solder, although one melts slightly above the other. While these can
work on brass to some extent, the joints will be weaker than those made with
hard solder. The melting points of these soft solders are all well under
800F, although there are intermediate types that will require hotter
temperatures. True hard solder is much different; it's also called silver
solder, (not to be confused with "silver bearing" solder which contains a
small amount of silver) and melts at temperatures ranging from ~1240 - 1365F
although the flow points are somewhat higher. Real silver solder is mostly
silver, and it's used by jewelers to make invisible joints in silver rings,
etc. (They also use gold solder, which is similar but based on gold
instead). Silver solder will work with brass, steel, copper and some (but
not all) other metals. It's too hot to melt with a soldering iron; you need
a torch to use it effectively. It's also important to have everything clean,
and to make the joints fit closely without any gaps, which this type of
solder won't fill. Use white paste flux (a different type than for soft
soldering) Handi-flux is one popular brand; your local welding store will
usually have some flux that will work - ask for "silver brazing" flux. To
get silver solder, look for a jeweler's supply company like Rio Grande,
Indian Jeweler's Supply, Alpha supply, etc.]
Andrew Werby
www.unitedartworks.com
wrote in message
oups.com...
Hi, Mike.
Looks like you have all the correct answers, already.
The rosin core solder is really meant for electrical/electronic
assembly. Electronic components normally are coated with a thin solder
coat during manufacture, so when the user solders, the flux doesn't
have much work to do in cleaning the work.
I think you are wanting to solder brass that does not have a solder
coating. In this case, the flux has a really hard job of cleaning all
the surface of the brass. Oil from your hands, dust in the air, cooking
fumes and who knows what else, have put a very thin layer of
contanimation on your brass. The flux you use will have to dissolve
this contanimation and move it away from the solder, as you apply heat.
Solder will not adhere to the brass where any contanimation is living.
I think you need to find some acid core solder. When this is heated,
the flux decomposes into an acid that eats away the contanimation layer
and lets the solder make contact with the freshly exposed brass
surface. This type of solder used to be available in hardware plumbing
sections. Plumbing now is forced to use lead-free solder, so I don't
know if the flux is still acid or not. The lead-free solder will also
work for your "hard solder" needs.
In all cases, be prepared to wash your project with hot soap and water
and then rinse will. Any acid flux left on the brass will still be
active and will eventually turn the brass to a green color.
Are you using a soldering iron to make the joints for your project? The
hard solder will require a higher temperature than lead/tin solder.
Perhaps 40-50 degrees hotter. Depends on the solder. Your iron may not
be up to the job if it is designed for lead/tin solder.
Good luck on your project. Let us know how it works for you and what
you learn along the way!
Paul in Redmond, OR
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. 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?)
.062 dia
8 oz.
I suppose that this is more a "soft" solder. What specs should I look
for in a "hard" solder.
Sorry for all the dumba** questions, but I gotta get this figured out.
Thanks
Mike