Heat Treating Oven

[KellyJones]

Thanks for that Fender. I was gettign a little worried that I was doing something completely stupid using charcoal.

Please also recall that the original post was about heat treatment, not melting. Having said that, how critical is it to use a diffuser in the fuel? Can I achieve 1650F by simply blowing air across the fuel?

thanks

[Fender]

Kelly,
Maybe, but you'll be doing it the hard way. Most likely only one end will get hot. Suggest you get a piece of 1 1/2 or 2 inch pipe to lay across the bottom of the pit, with one end sticking out of the side about 6". put a pipe cap on one end. Drill 1/4" or 3/8" holes in it until it looks like swiss cheese. Put the blast into the other end. Start with burning wood kindling. Pile charcoal and the work pieces on the fire. Sock the blast to it. You'll have much better results. The cold air coming in keeps the pipe from melting. When you have the work pieces up to the desired temperature, reduce the blast to almost nothing (but still some blast), and let the charcoal burn out, so the pieces cool slowly.

[steamin10]

Kelly, Fender: Dont mistake my comments as being too negative. Brass, Bronze, Gold, Silver, just about any castable metals have been heated with charcoal for a thousand years through history, all the way to the Bronze age. I am simply talking practicality, and the details to make it work, in our modern world. A difuser plate under the fuel with the vessel nested on top, is as simple as it gets. It can work. Not for me, I moved on.

I welded three steel auto wheels together and cut the centers out, for a tubelike shell to hold the charcoal. I tried to reduce some chips to a usable lump, and failed. Better off to give it to the scrapper, and get good material. My furnace was unhooked, so read that as too lazy to blow a half day setting stuff up to run a few pounds of trash. Great experiment, I know more now. Failures will always teach you, pay attention to them.

Dont expect to avoid a learning curve. It is always there.

[Fender]

Dave, agree that many people get good results from gas or oil, and if you are set up that way it is more convenient. All the commercial bronze foundries I've been to used gas. I don't have gas at my house (that came out wrong ) and I'm not set up for oil, so charcoal it is.
Kelly, what you are doing is more like blacksmithing. A blacksmith forge brings the air in from the bottom also, from what I have seen, although I have never actually tried to set up a forge.

[steamin10]

A neighbor behind me, 2 streets back, was a forger/blacksmith/ferrier. He was truly a man to give a hammer to. I thought I knew about a Smiths forge. Not so. They are either talored for one particular job, like knife forging, or big and general for making all those things blacksmiths do, Hinges, ornaments, and wheel tires for wagons. Simple? Yes I was. It is another fading art.

I guess I am easy to amaze.

[already-old]

Sorry Iam a little late on this one. But any one needs to know how to anneal a piece of ferrous metal here is how I do it. Crude but works well.

I just put it in the wood stove build a HOT fire, over the piece that needs to be annealed keep burning watch the piece till it glows a bright red. Work the ash up over the metal, like bury it let the fire go down, pull the metal out in the morning or about 10 to 12hrs later. Dont go after it with your hand the metal will still be hot enough to burn you. I guarantee that if it will soften this will do it. No stove you say or really a big part dig a hole in the ground build a fire around it keep hot till it glows red bury it in ash leave it.