[lukewarm]

I personally use a metal crucible. Heat it to red heat before using it to buildup an oxide layer to protect the steel from the motel aluminum. Always check your crucibles before using them with a tap from a hammer and toss it out if it's suspect. Steel pipe with a endcap welded on works well.

As for your fuel source are you using charcoal you buy for barbeques? If so I'm not sure its the best option as a large component of it is clay binder etc. I've used two setups, my first was a waste oil burner (messy and a pain to get started) and my second was propane. I prefer propane! There are a few ways to make good propane burners, A simple homemade propane burner is a good place to start.


WARNING - be very careful! Always wear protective equipment and ALWAYS watch out for water. A explosion of molten metal in your face will ruin your day!

[Burningleon]

Any idea where I can find some steel pipe. Cheapest place I've found around here for even a 6 in segment of 4 in diameter is 12 bucks. That isn't much but considering I already have all the stuff I need for a refractory crucible it just doesn't seem worth the hassle of driving into the city to get it.

I used charcoal to sinter it but my heating source will hopefully be the propane burner. I have already constructed the burner in your link and will be testing it as soon as I have a new crucible.

[lukewarm]

12$ will probably be cheap compared to the hassle of trying to get a refractory crucible to work. It will also save you fuel as the refractory crucible won't conduct heat very well.

If you haven't read this guide yet it's very informative. The Hobbyist's Guide to Casting Metal--2nd Edition (print)

Good luck.

[jimmy111]

About the furnace lining. You probably didnt get the charcoal at the bottom burning well before you filled it full of charcoal. Do it again and keep only about 4" of charcoal burning in it on the bottom.

About the crucible. You probably didnt make it very well. It has to be rammed (compacted) really good. If the consistancy is not equal it will crack, It also has to be cooked quite slowly and evenly the first time too.

Regardless of what others are saying here, ceramic crucibles are the best. You dont want a crucible in that conducts heat quickly. It will just result in oxididation of the metal and the alloys in the metal. A steel or iron crucible will get hot quickly. Way above the melting point of the aluminum. The Magnesium which is the mail alloy in the aluminum will rapidly oxidize and cause problems with the casting unless you add more.

But untill you learn how to make them properly it will be cheaper for you to just buy one.

[Burningleon]

I had the charcoals in the bottom burning pretty well before I added more. Can you possibly give me some examples of what it is supposed to look like so that I know what I am looking for and what I have that is wrong?

[jimmy111]

Dont worry, it just takes practice.
You probably have too much air then. Just keep the charcoal at 4" and try to turn the air down somewhat if you can. Try again.

[Burningleon]

Alright. I'll give it another shot since I'll have to fire my new crucible too. What should we be looking for in an end result?

[awerby]

Or is this about the process - doing everything "from scratch"? Because if you're really interested in good results, just buy yourself a crucible, preferably one made from silicon carbide. Steel crucibles aren't good for aluminum, since the metals aren't compatible. They aren't safe, either, since they can fail suddenly. But they are better than your ridiculous home-made crucible, which is an accident waiting (NOT VERY LONG) to happen. If you've never been in a situation where molten metal is flying around out of control, take my word for it - you don't want to be there.

The casting of high-melting-point metals can be done in a small studio, but it's an inherently dangerous activity, even if you know what you're doing, and have the correct equipment. If you don't really know how to do it, are ignorant of the very real dangers involved, and are too cheap or foolish (or both) to get even the most basic equipment that reduces the risk, then you're going to end up in a hospital with a long time to wish you'd listened better.

Sorry, but somebody needed to say this...

Andrew Werby
United Artworks- Sculpture, Jewelry, Furniture,and other Art Objects, plus Art Resources, Techniques of Sculpture, Jewelry and Lapidary, an Online Bookstore, and a Custom Art Referral Network

[jimmy111]

Ive been in this business since the 1960's and have seen only 3 people in all that time be stupid enough to burn themselves with molten metal. Yet I ve heard the same line that awerby is spouting beaten into everyone to the point that they are afraid to work on or try anything new. This line is generally said by people who have little to no experience in foundry practice.
There is not a thing on this forum that wont kill you if you let it. It is all dangerous. At least the guy has the initiative and ingenuity to try to do it himself. Traits that are sadly lacking in todays America.

[awerby]

Who wants to be the fourth? In the foundry business, you generally deal with people who basically know what they're doing, and use professional equipment when they do it. Yes, it's still possible to get hurt, but the odds are better for them than for someone who's seen a You-tube video or two and read a couple of newsgroup postings and decides to build a foundry out of stuff he found at the garden store.

I'm all for people trying new things, but sometimes I see an accident about to happen and feel the need to speak up. This guy talking about making a crucible out of clay and perlite is one of those times. When that thing fails suddenly and drops a lot of hot metal on the concrete floor (or down his tennis shoe) will he know that the metal is about to start raining upward?

I've only been doing this since the Seventies, but I've run my own foundry, and I've had enough hands-on instruction, and experience, and seen enough near-misses to know what I'm talking about. Molten metal is just too unforgiving to mess around with casually, without knowing what you're doing. If the guy wants to go ahead anyway, that's fine, but it won't be on my conscience when I hear what happened to him. I still think he should at the very least get a real crucible. Hopefully, someone else will tell him the other things he really needs to know, like pre-heating his ingot molds before pouring metal into them.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[headsmess]

this was my first attempt well, ok. 2nd.

but um.... last time i mix nice clean extrusion with um.... dirty beercans n some ground off scrap with epoxy mixed in...

[nomedia="http://www.youtube.com/watch?v=eaSHo9qgNt8"]‪castingskull in aluminium‬‏ - YouTube[/nomedia]

there was a lot more light than it looks?

[CyberGolem]

So I think both Awerby and Jimmy are both correct: The guts to try something new should always be governed with caution and respect.

If BurningLeon is wanting to learn how to scratch build crucibles and such he should go for it, but if all he's wanting to do is to make stuff, then he should just buy the right tools to do the job and start making stuff. This is my preference since it allows one to understand the capabilities & limitations of the tools being created. Once this is understood, the process of creating things that create things are easier to construct --usually.

In the end I just hope anyone doing this stuff is willing to invest as much in safety gear as in research materials. There are plenty of videos online with guys pouring molten metals wearing sneakers and no other safety equipment. It make me wonder how long it will be before I see those same people as contenders for the Darwin Awards.

—Chaz