A small forge for Blacksmiths, not a forge for small blacksmiths.
A long-term goal of mine's been to have a forge small enough and well-mannered to keep in my suburban garden, so that means no bituminous coal. I considered a Gas forge but when that turned out to be impractical for the scale of work i want to do, i looked elsewhere. Plus, with a gas forge i'd probably have ended up blowing my legs off.
So, suburban (so no smoke) and i can't use gas.... the only alternative i could see was charcoal. Finding a lost middle-american civilisation in among my socks would be considerably easier than finding the kiind of charcoal i need in the amounts i need. -everyone wanted to sell me a few tons at least-
Eventually, i found something called "smokeless fuel" seemed to be pure carbon or something, so because it was only A?1.75 for 10 kilos i decided to give it a try...
Step 1: Find something to make the forge in
I WANTED to use a wheel from a car to do this but i couldn't be bothered going all the way to a place to get it only to carry it home and eventually set it on fire, so i looked closer to home. I ended up using a 12 inch stainless steel cake tin. I never once thought i'd be making a forge in something that vould have been used to hold cakes but it worked really well.
The first thing we need to consider when building a forge is the ariflow. Too much and it gets far too hot. Not enough and it doesn't burn at all. To get the air into the forge, we need a hole through which we can out a pipe. Wheels come with ready-made holes. Cake tins do not. Ergo, i had to make one. "It's only thin steel, what can possibly go wrong?"
I spent something like 40 minutes getting a hole big enough to put the pipe through. SO: this step's instructions: Through Fair means or Foul, Make a hole big enough to fit the pipe through. Make sure the pipe doesn't go too far in or not far enough in. about 1.5 inches was right for me.
Step 2: Add Refractory
"THE FIERCER THE HEAT, THE HARDER IT GETS!" bragged my fire cement. The Refractory reflects the heat back up into the fire, making it more efficient and less likely to melt its way out the bottom of the...cake tin (shudder) It's going to get Seriously hard.
Whatever you do, don't use something that expands too much. Chances are it'll do this at the worst possible moment and carry a cargo of hot coal into your eye. Only use a proper refractory. Mine was rated to 1250 degrees centigrade, lower than I wanted but still plenty high enough. Put about half an inch on the bottom and build it up round the sides leave a working area about 8 to 10 inches wide and 4 deep at least. Make sure that no steel peeks through the refractory.
Allow the refractory to set as per the instructions that should have come with it. Mine needed to be fired immediately after being applied, so no pictures there. Others may need to dry first. Follow the instructions and only fire up the forge when the stuff's ready.
By demand, popular or not, here's some pics on how i added the refractory. I took these the afternoon after i fired it up so the refractory's stained and sootied but i think they get the point across. The refractory should be fairly thin on the bottom, thickish at the bottom of the walls, getting thinner (but not too thin) towards the top. One pic's just the forge itself with nothing added, the other's a pic with the empty refractory pot in for a sense of scale.
Step 3: ON FIRE!
Also known as lighting the forge.
Once you've placed the pipe the correct distance into the forge and applied the refractory, being careful not to obstruct the airflow and to leave a working area big enough for the work you plan to do, it's tome to test-fire it. I suggest doing this at least once before doing any work, just to get a feel for it. I lit mine by putting some wood shavings and paper into it and lighting them, then adding more wood onto that until i was happy that it wouldn't blow out when i turned the blower on (once again, i forgot something important. The blower pushes air through the forge to allow it to reach the correct heat. The blower goes on the end of the pipe that goes into the forge. It needs to be close enough that it doesn't lose too much huff over distance, but far enough away that it doesn't melt with the heat.) Once the blower's on and some more wood's on the fire, put the fuel on, whether you're using coal or charcoal or whatever else. Don't use wood for lots of reasons. It'll take a while for the fuel to take. Put more wood on as needed and put fuel over any gushes of flame coming out (don't panic, the flames from the wood are only 6 inches at the most) Soon enough the wood you used to start the fire'll have burned out and the fuel will be alight. put more on as you need to, but don't put too much on. If it gets higher than the rim of the forge, it's too much. In the picture you can see some bits of wood poking out the sides. The forge itself is on a cinder block (i think i could find a way to get porous cinderblock into ALL my instructables if i tried) Also seen is the hi-tech air blower (old hairdryer) and the space-age way of ensureing that no air is lost in the transition between blower and pipe (sticky tape)
Step 4: STILL ON FIRE!
After a while, the forge should be burning well enough for you to start work. The coals in the middle of the fire should be glowing a bright-yellow colour. When you're working with the forge, when you take out the bit of metal you're working on, turn the blower off. The fire won't go out and you'll save some electricity.
When using coal, look out for clinkers, they stick to everything. I'll post more into on this instructable as i get it.
Step 5: LESS FIRE!
To let your forge fire die down simply turn off the air from the blower and leave it. It'll burn down on its own given enough time.
Putting a bucket of water on the forge will be disastrous. You'll get a huge plume of steam laced with incandescant coals, not to mention the fact that you'll give the refractory thermal shock and make it explode. Throwing a bucket of water on it is one of the worst things you can do. Actually, this forge is as safe as a garden barbecueue when handled sensibly but there are serious hazards. Don't let children or animals near it at any times. Don't work if you're preoccupied, drunk or tired.
Read up on the symptoms of carbon monoxide poisoning. If you start to show symptoms, turn it off and get away. NEVER use this in a badly-ventilated area. Always outside.
Step 6: Odd Stuff I Probably Left OutOK then, don't be stupid, etc.
You'll want to get a poker or something to move the fire about with, i used my tongs. I'll probably have an instructable on making/finding a cheap and effective anvil soon enough.
Have Fun Forging!