If I may just add a few thoughts about soldering steel. I would
recommend Easy Flo flux to use with Easy flo solder. Use the
round wire solder. Make sure that the steel is really clean
before soldering. Make sure the joints are really close. Put flux
on to the joints before bringing the joints together. I wouldn’t
get the steel too hot, perhaps a very dull red when the flux
melts and goes runny. Easy flo flows very quickly hence the name.
It should go through the joints very quickly, just a matter of
seconds. In the UK both the solder and flux are available from
Johnson Matthey, I can’t say for the US.
Richard Whitehouse,
Silversmith,
Ardleigh Workshop,
Ardleigh,
Colchester,
UK
I know that one would braze or as jewelers call it, solder, with
brass. I also know that one would buy the brass in rod form
already coated with flux. My question is – when you braze
steel, how hot are you getting, do you have to apply any flux to
the metal pieces you are joining? Please help
The flux coated brazing rod is probably 58% copper- 38 % zinc that
melts 1590 F- 1620 F it does not need extra flux on the base metal.
You can also buy unfluxed rod and a borax brazing flux that you
apply to a heated rod by dipping in the flux.
H & H’s Brazing Book will be available from Ganoksin shortly.
Stay tuned
hanuman
My question is -- when you braze steel, how hot are you getting,
do you have to apply any flux to the metal pieces you are joining?
Generally, when I braze something that’s steel, I use an uncoated
brazing rod (usually 3/32") . After heating the tip of the rod a
little, I dip it in a can of flux. The flux adheres to the rod for
the depth that it was inserted in the flux. I’ve never fluxed the
steel being brazed. If the area being brazed uses more of the rod
than that which is fluxed, dip the rod in the flux as required.
I’ve never looked up the melting temp of the brazing rod, but the
temp is probably between 1700 & 2000F, the range of most brasses.
when you braze steel, how hot are you getting, do you have to
apply any flux to the metal pieces you are joining?
BJ, you can buy brazing rods coated with flux, but I can’t recommend
it because the coating tends to crack and fall off. In my opinion,
it would be better to do one of two things. Either buy the black
flux which is available at welding shops and is stable at higher
temperatures than the usual flux for silver soldering, or buy a can
of dry flux meant for brazing and dip your brazing rod into it
periodically as you are brazing.
As to how hot you need to get, in order to braze, check the melting
point of the brazing rod. The metal you are brazing must get at
least that hot, in the area of the braze. If you are brazing large
pieces of metal, you will need an oxy-acetylene torch, in order to
get and keep the metal hot enough for the brazing rod to flow.
Selecting the right fuel gas for brazing is affected by what you are
brazing. Acetylene produces the hottest flame but heat and BTUs are
concentrated in a “pinpoint” at the tip of the inner flame that is
best for joining smaller pieces where you want heat in a specific
area. Natural gas, propane, and MAPP have a more bulbous, soaking
flame that works better on larger, tubular pieces, say 1" diameter
and larger, where a broad even heat is more desirable. Acetylene
works on bigger pieces but you have to keep the torch moving so as
not to overheat the work and possibly cause melting or other surface
defects. A torch with natural gas, propane or MAPP requires less
movement and heats a larger area, drawing the braze rod and filling
the joint better.
My company has experience with brazers joining all combinations of
copper, steel and brass with a range of filler alloys and invariably
brazers like the bigger flame of natural gas on larger pieces.