Metal Casting Zone

Hello evryone,

is there anybody here having experience with coal/wood operated furnaces?
How high can the temperatures reach up?

I'm thinking about my first furnace for the beginnings and I'd like to try a charcoal/stone coal operated furnace ,or wood operated,that's why I'm asking here ,I'd prefer that to a gas or oil operated furnace.
Main reason for choosing coal is the permanent switch in prices for oil and gas here,2nd reason is a personal disfavour to gas n oil because of bad experiences.

Thanks,Julian

It will work absolutely fine. Consider that the major fuel source for metalcasting of all kinds for thousands of years has been wood or charcoal. In a backyard crucible style furnace you can do brass with relative ease, perhaps iron with the right fuel and sufficient air blast. The nice thing about charcoal is that it is fairly self-insulating, so furnace construction is simplified, and the need for highly refractory linings is less. Portland cement based refractories would be absolutely fine for a charcoal furnace. You will still need some type of blower, but it is not as critical to have a high powered one. A hair dryer would be sufficient for a small furnace (one with a cool or no heat setting so it won't burn itself out).
If you wanted to build a furnace that you could switch over to gas or liquid fueled burners, build a tangential-tuyere style furnace and try a woodgas burner. I am experimenting with them myself, and I will have one that will eventually melt iron easily. Google "Dassifier" or check out www.woodgas.com . I will have to look up the exact link for you. The nice thing with a woodgas burner is that you don't have the crucible surrounded by and supported by coals, and it is easier to manipulate the crucible. You also don't have to open the furnace to add fuel. They are somewhat cantankerous to get going, and may be a little sensitive to the quality of the fuel, but myself and others are working on it. Jammer, another poster here, is experimenting with them also.

Thanks for the first answer
If I aim to cast bronze,brass,aluminium and steel ,does it work??

Steel? I doubt it. If you have a charcoal furnace that will let you melt steel I want to see the plans... Iron would be pushing it. Oil burning furnaces would have a hard time melting steel, the pouring temp is pretty close to 3000F. I got my foundry sand off a gentleman who was selling his foundry setup (age and health issues), and he used an electric induction furnace to cast steel. Of course, he also had a generator the size of a VW van due to the fact that it would have been almost ten times as much to run it off the main line power. I could have had the whole setup for a measly $60K (US dollars). To melt iron efficiently with coal or charcoal you should build a cupola style furnace. It will also work for brass and bronze. Or were you referring to the woodgas burner? I have melted brass with mine, and it's just a gumped up mess, I think a properly constructed one should be able to get a furnace to iron temps at least. It's a few (dozen) projects down the line, but I plan an improved version before too long. I have a pic of it on photobucket, I'll post it in a few.

Okay, here is the Odd Duck Foundry version of Agua Das's "Dassifier", a woodgas powered foundry burner. Please note the expensive and carefully manufactured components...



Here is the link to the diagram showing how it works more or less.
www.woodgas.com/history9.htm
My gassifier is a little different than the one in his diagram, but is essentially the same.

Non ferris metals are not a problem, steel and iron i doubt.
check out my el cheapo furnace on the site under casting furnaces.
this thing is about as low teck as one can get.

i use wood and gas. i tried coal and the neighbours complained about the smell and smpke. manmade wood product are great and so is sawdust but some experience is required to manage air flow to get them burning right. i thought about woodgas! i love the idea but useing a burner under the generator doesnt make sense to me fuel wise so i use a gas burner directly into the furnace and add small amounts of wood product.under the heat of the gas burner the wood goes to charcoal very quickly.

Check out the diagram on the link that I provided. There is no separate burner, the gassifier provides its own heat source through incomplete combustion. It burns just enough (under ideal circumstances) to pyrolize the fuel directly above the hot zone. The cycle continues more or less automatically, with fresh fuel dropping into the pyrolisis zone by gravity. It smokes some on start up, but I had it figured out to the point that i could get a sustained flame in the furnace in two or three minutes.

OddDuck, are you trying to recuit more Woodgas converts?

I want to play with mine some more this spring. I saw a video where a guy had just a little fuel in on the start, got it hot fast and then added a little fuel at a time. It was going pretty quick and had almost no smoke. The last time I tried mine the wife made me take a shower before I could eat supper.

I so have to build one of these!!!!