You need a real crucible (probably a clay/graphite at those temps) for those
temps , and green sand or oil bonded sand for the mold . What kind of heat
source and enclosure di you have in mind ? There are naturally aspirated
LPG/natgas burners that will put out that much heat , but forced air is
probably more efficient . I suggest you start with aluminum and work up to
the hotter melting metals ...
If the next question is "can aluminum be melted in steel or irons pots"
the correct answer is no, unless they're coated. Molten aluminum will eat
away and dissolve the steel, and far faster than you might imagine at
Did you read that somewhere or do you have experience to back it up ? I have
been using steel containers to melt alunimun for several years , and the
majority of damage I see is caused by the flame . Get too much air and it'll
scale badly and eventually develop holes . Aluminum will dissolve a very
tiny fraction of a percent of iron , but absolutely not the kind of damage
you're attributing *under normal conditions* .
In the literature about aluminum casting, you'll find lots of expert
accounts about the effect of melting aluminum in steel or cast iron
crucibles -- it's bad. There also is technical info on the effects of
picking up iron in aluminum alloys. It damages the malleability of
aluminum, to the point of making it downright brittle if you let it
pick up too much.
There was discussion in some amateur casting source about using heavy
stainless-steel pots, which supposedly works, but I wouldn't count on
its technical accuracy.
If you read David Gingery's original casting books, he made his
crucibles by welding a bottom piece on steel tubes. He also welded on
a couple of lugs so you can get a sure grip with the tongs. But he had
a solution for the iron pickup: Make a thin slurry of fireclay, pour
it in the crucible, slosh it around and pour it out. Then let it dry.
Do it once more, and then bake the crucible a bit to be sure it's dry.
You don't have to actually fire the clay.
That solved it, he said. I never tried it because I had some ceramic
OK, I have my results.
It is a BAD idea to melt copper in a steel box. It does eat the
steel. The steel box is ruined. I was kind of lucky that copper did
not spill. Also, an electric furnace takes too long to melt it.
In addition, the cast iron pot was cold, not clean enough and the
bottom of the casting is porous as a result.
Not in my experience. My crucible is steel and has no visible signs of
being dissolved away. Maybe in time it would, but that time would be
long after it had satisfied all my needs.
Not to say that a "real" crucible wouldn't be better, but steel does work.
On Tuesday, July 7, 2015 at 4:19:06 PM UTC-4, Ignoramus11126 wrote:
Let us know if you have problems with the copper sticking to the steel. I have no experience. But silicon bronze is 96% copper and sticks to steel very nicely. Well it least it does when the steel is clean.
I don't know about this but wondered how copper was added to tin in
Britannia metal (modern pewter, often 92 6 2 92% tin 6 % antimony, 2%
copper) and was told by the producer that the copper was just added to
the molten tin and it dissolved like sugar in a cup of tea, made sense
as it is the same process, the tin melting at a far lower temperature
than the copper. Maybe a look for metal solublity may give some insite,
the soldering irons I like, Antex, have iron plated copper bits to stop
the copper dissolving in the molten solder, probably fairly common practice.
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