I have been involved in a local school (Portland Waldorf School) which has a blacksmithing program. There have been complaints about the smell of the coal burning and so I found out that charcoal can be used as the fuel instead of coal/coke. So I am building this charcoal maker so that the children can see how to blacksmith without coal.
There are health benefits too! Coal produces sulfer when burned which can combine with water in your lungs creating sulfuric acid (acid rain) as well as the water in your sweat. If this helps someone have a better experience blacksmithing, I will be happy.
Here I describe how I made a charcoal retort. This is also known as the "indirect" method of making charcoal. Basically you take a metal container and cook it until all of the volatile gasses leave the wood.
step 1-Make the container
I decided to go ahead full bore for my first charcoal attempt. Many online sources indicate that they started out with small metal containers, but I figured a 55 gallon drum would be the best bet. So I found a recycled drum merchant on craigslist, paid $25 for a drum and proceeded to cut into it. I took some 3 inch round steel tubing and made the retort tube. This is …
step 2-provide holes for gasses to escape and Burn
Next, you need to provide holes in the pipe under the drum. The point is to create a large burner-like thing. I drilled 1/4 inch holes every 3 inches in both sides of the tube. Later I thought that might not be enough so I used my die grinder to cut 3 slits in the top of the pipe so that the gasses would be directed more directly at the drum.
step 3-collect wood and take your stuff to the burn site
At first, I figured on using all pallet wood. So I loaded everything in my van to take it to the burn site. Below you can see that I have everything loaded up and ready to go
step 4-load it up and cover it to keep the heat in
On my way to the burn, I realized that I did not have any way to keep the heat in the drum. So I stopped off at Lowes and bought 3 pieces of cement board at $9 each. You can see that I put a tray below the assembly in an attempt to have a low impact on the site. I did not want to burn the grass where I was doing this, and we had a copper fire place on hand. I think …
step 5-more on trying to keep the heat in
Here you see the cement board leaned against the assembly. I have some left over KaoWool (kiln refractory blanket) from a forge project so I draped that on top to keep the heat in the drum as much as possible. I draped chains over it to keep it on the drum
step 6-Load the drum with wood
Here we put some wood in the drum. this is Fir heartwood which my friend uses to heat his home. They are mill ends from a plywood mill. We filled the drum that much.
step 7-Start a fire
Pile wood up under the drum and set it ablaze. An old indian showed me how to start a fire without flint, steel, paper or tinder. He called it a weed burner and it's fuel is propane. It works real well.
step 8-burn for a good long time
we lit the fire at 10:30AM and did not see gasses come out of the tube below until about 3PM.... We wound up burning about 5 pallets, plus 2 moving boxes full of scraps from the school's woodshop. Probably about 150 lbs or so. There is about 120Lbs of wood inside the drum. not as efficient as I had hoped...