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Brass melting problem


#1

Hi there, today i was tryed to melt the brass alloy,i was used
Smith little torch with melting tip (oxygen & natural gas) but it
can`t melted properly ,i tried using hard flames & take about 45
min longer but it still in grains condition, only some melted
about 20% of them, last few days i was melted copper at the same
weigth with the same torch but it melted properly. i hope some of
you who know how to melt this brass alloy could give me some tips
to solve this problem. i only have copper melting temperature &
what is the brass temperature?
Paul


#2

Paul: I don’t the Little Torch melting tip is capable of melting
what you’re trying to melt. My first attempt like this was trying
to melt some brass alloy that came with a sand cast kit and all I
had was the Little Torch and melting tip. It just plain did not
work, even with acetylene/oxygen. You need a bigger torch, plain
and simple…Dave


#3

Paul Lee, I’ve had some experiance melting brass, copper and
bronze. Brass, being an alloy of copper and zinc melts at a lower
temperature than pure copper. I wonder if you might have a
problem with heat dissipation, using such a small torch, or
perhaps have not fluxed completely. I find that with castings up
to 8 pounds of metal that brass and bronze are much easier than
copper due to easier flow characteristics. But I use a big
acetylene torch or a propane foundry when melting it.

There is a health warning about these metals. Zinc vaporizes and
if one overheats the metal they can get metal fume fever, the
same fever they get from welding galvanized steel. Also, if one
melts coppers and bronzes from unknown source they run the risk
of getting in to some beryllium copper. Beryllium is terribly
poisonous, gets in the lungs and destroys them over several
months. It is popular nowadays, used in part fabrication by big
corporations which don’t give a d*mn about whether the people
who recycle their parts die or not. There is no easily available
test for it as far as I know. IMHO it should be banned.

Geo.


#4

Hi Paul. Will you answer a few questions for me please? I think
we need to know a few basic facts before advising. 45 mins sounds
like an enormous length of time. You see, with my oxy-propane
torch I melt 30 grams of brass in a matter of 30 seconds, using
an easiflo dry flux, an open 65mm crucible. I successfully cast
melted brass screws in a gravity sand mold.

Here come the questions.

  1. How much brass (grams) are you trying to melt?

  2. What are you melting it in - describe the shape and size.

  3. What flux are you using?

  4. Is your flame oxygen-assisted, compressed air, or plain room
    air?

  5. What shape is the brass in? Are they brass screws? Wire?
    Sheet? How small? How uniform in size?

  6. Melting point: the liquidus is when the metal is fully
    liquid, and the solidus is when it’s fully solid on cooling down.
    Regarding temps, I’d say:

metal solidus liquidus
copper 1083C 1083C (1981F)
90/10 brass (gilding metal) 1055C 1070C (1931F)
70/30 brass 920C 955C (1750F)
90/10 bronze 930C 1010C (1850F)

Brass is copper with zinc, and sheet brass is usually 70% copper
and 30% zinc. The zinc boils at 900C so that’s the white stuff
coming off the melting metal and flying round the place. Bronze
is copper alloyed with tin.

Looking forward to your reply.

Brian

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