Instructables

Setting up two forges...

Basically I have two ideas, one of which I'm pretty ready to make now and another which will take a little longer to make, one is a tiny forge, like desktop sized, for working at home and the other is a much larger forge for big metalwork projects, thankfully the large one will actually require less parts scavenging as I have plenty of acces to scrap material and there's a brickyard over the wall from us which will do me the necessary materials very cheap, mainly because I did a little forklift driving for them for larger heavyweight loads over three tonnes. That's all well and good a big one I can get my head round easily enough, But. How would I go about making a tiny forge and I mean miniscule, it's main purpose is for heating to cast for my specialist parts I prefer making and the other is for low material single cast jewellry my mum makes (she used to own a jewewllry business and still makes the odd bespoke items. But my main question is how I can build a reliable yet compact forge and furnace, from what I have sitting around I'm sure I can come up with a decent fuel source, ranging from butane torches and stoves, both of which can do propane and I could go to natural gas (we have a special plug out the back for gas barbeques the house had it when we came...) but my other questions are a bit more odd, first of all what would make a great crucible, I need something that'll be fairly invincible to the hardships caused by life, as the other liely user of the forge and furnace is very forgetful and sometimes accident prone. Next up is the housing, would it be feasible to use a single block of thermocrete cast to make the main furnace housing, as in everything is but the fuel and air source holes and the crucible hole would be one block, as it stands that seems like the best way to make it simple and effective, plus it would be pretty airtight where needed. Next question is the fuel and temperatures, I know that butane at full combustion get 1300C and 1000C is a practicable operating temp. for a butane item but what about propane or even natural gas, since it would be very cheap and clean burning... I'm a bit of a noob towards this end of the scale, I can make stuff hot and I can do alot with these things but actual forge and furnace making is a little beyond me on this scale, however I can think of several advantages to my baby furnace, including the practical movement of it, as it could be self contained very easily. The pic was just one of the last pictures that's remotely intersting I uploaded, however it raises it's own points as the jet engine basically welded all it's components forward of the flame together.

I realize I'm fairly new to this myself, but... First, you would take a small(Really small) bottle of butane for filling refillable lighters. You can get these just about any gas station or supermarket. Go outside, and CAREFULLY depressurize it. When you are sure it's empty, wait a little longer just for safety.(Don't do it around open flames, running engines, or anything else that might ignite the vapor, cause that would be BAD). After the safety wait, cut the Top(the end with the nozzle) off SLOWLY with a hacksaw, in case of lingering vapors. Wait five minutes, then drill the bottom of the tube to size for your burner. Coat the inside with 1/4 to 1/2 inch of refractory cement and let set per instructions of same. When it sets, fire it up once to get the feel of it, and get after it. Would advise you to build a small stand for it.
That should be 1/8 to 1/4 inch of refractory cement, sorry. Any more, and you would have no working space. But you could always use a little on the outside, if it gets to hot, but just remember to follow all instructions on the cement.
killerjackalope (author)  LittleJoe75145 years ago
Wow, thanks, I'm glad you dug this topic up, I suspect that a modified camp stove burner could be a good fuel/air source, running hot air in from a small source not even as strong as a hairdryer, maybe a simple mini blow heater made from a computer fan and a grid of resistance wire. Mixed in a simple venturi and burned in the bottom, with a sensible design that uses the whole top as a crucible cover a reasonably efficient furnace could be made. Funny I have an empty can of butane kicking about...
LinuxH4x0r6 years ago
Keep me posted if you make one. I might make one this fall and I could use all te help I get. Good Luck!
killerjackalope (author)  LinuxH4x0r6 years ago
Yeah I just need a bit of help getting the right idea, I can deal with heat, air and fuel but a forge is a little bit confusing for me, despite my insane 'super jet' design I have for a much later date, I have little understanding on the finer points of forges and furnaces...