Hi all,
I have the little torch with melting tip that I use for casting, but
it’s too little for my purposes anymore. Up to 100 grams is ok but
more than that is pushing it. So, I’m trying to decide if I should
get a bigger torch, since I already have oxy/acteylene tanks and
regulators, or if I should switch to an electro melt. I mostly cast
3x4 inch flasks with 10 to 20 items, but I need to get more bang for
the buck out of each flask and so I want to move up to 3.5X5s,
around 200g or so. Unfortunately I don’t think the little torch can
handle the charge. I could spend the extra on an electromelt but I’m
not sure if it’s really all that much better than a torch, or at
least enough to justify the cost difference. Any suggestions are
appreciated.
Those who say, do not know,
Those who know, do not say,
Except on the Orchid.
For casting, electro melt is always better unless you have a reason
to melt in highly oxidizing environment, but even that can be done in
electro melt using oxidizing flux.
Casting with the torch is a shortcut and it is not a recommended
practice.
I could spend the extra on an electromelt but I'm not sure if it's
really all that much better than a torch, or
I don’t think there’s really an answer to your question - it’s a lot
of preference. My own thought is that if you buy a larger torch,
you’ll be able to solder, weld and braze a wider variety of things,
while the furnace will just melt metal. 200 grams isn’t very much,
anyway. One shop I worked in used a furnace to melt 50 ounces of
silver, and then they poured it into crucibles for casting, but we
were casting 300 flasks/week there, too. I think a furnace would be
handy, too, but not handy enough for me to buy one…
I have been using electromelts while vacuum casting for 30 years and
have never used a torch to melt metal so I guess I am somewhat
prejudice.
I strongly suggest you move on to the electromelt if you are vacuum
casting I suggest you buy the electromelt with the controller
option. This will make melting the metal much easier. The non
controller unit must be watched closely and you have to fiddle with
the temperature control knob to prevent the heating element from
burning up.
Advantages of using an electromelt:
The temperature of the molten metal will be consistent between
pours. You can melt enough metal for several pours. I melt around 60
to 70 ounces of silver in my larger electromelt. The controlled unit
will hold the set temperature as long as you desire.
You are melting the metal in a reducing atmosphere. Pouring the metal
into the mold is like pouring coffee into a cup.
Disadvantages of using an electromelt:
It takes time to melt the metal. It takes about 40 minutes to melt a
charge of metal in the smaller electromelt and more than an hour in
the larger unit.
The graphite crucible will deteriorate in time. I find that I have to
replace the larger crucible after about 20 days of casting.
Lee Epperson
I’m not so sure I agree with you. A slower process implies that it’s
better, but isn’t always so. As long as you watch your flame and
don’t sut up your gold, and pour THROUGH the flame, acetelyne is my
preference. Propane takes too long to melt, electromelt cost a whole
lot more than a torch set up and probably burns a lot of electricity.
Stanley Bright
These are all valid points, but electro melt has one distinct
advantage. The precise temperature control. In my opinion this is
overriding factor. To achieve good crystalline structure of the
alloy, it must be poured at precise temperature. Lower that optimum,
and casting is incomplete, and higher temperature would produce
alloy with large grain which is inferior and also could produce
porosity. If all I need an ingot then torch is fine, but for more
elaborate work, precise temperature control worth all the
disadvantages.
I usually only melt what I need per flask, which means the first
batch takes about 20-30 min, and each successive melt during that
cast is 5-10 min…which usually gives me just enough time to get
things ready for the next round and quench the previous flask.
My crucible does wear out quickly though, as I am casting at higher
temps since I’m doing fine work…but the crucibles are not that
expensive, and well worth it for the advantages of not having to
coordinate my casting with wielding a blow torch!
Jeanne
http://www.jeannius.com
http://www.silverthreadsfiligree.com
Don’t even think about it! Quit wasting valuable time and buy the
electromelt. Very well worth the cost and much safer to use than a
torch and crucible.
Ruthie Cohen