Does molten copper stick to steel or cast iron

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 first.

Right now, just for trying, I am using a small 2,400F electric heating furnace. Melting copper in a steel box.

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* .

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.

Bob

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 crucibles.

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.

Dan

The biggest problems melting copper are dissolved oxygen and hydrogen. They cause porosity and other problems. That's why they use electrolytic refining for anything that requires clean copper.

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.

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.

experience, using Lodge 2 cup cast iron fat melting pots with aluminum. I had no idea what was going on at first.

"Ignoramus11126" wrote in message news:- snipped-for-privacy@giganews.com...

I'll bet that would have ruined the furnace.

Why didn't you put the steel box on the aluminum plate, too?

This just in:

Live & learn.

Thanks for letting us know your results -- the best mistakes to learn from are _other_ people's mistakes!