DIY Casting Furnace

Line up three cement blocks on the ground so that they form a 30-inch wall. Make sure that you are on sand, rock or some other nonflammable surface.

Set two more blocks against the wall, on the left end, on the side facing you. You should now have an L shape. Do the same on the right end. You should now have a U shape with the open end facing you.

Place the remaining two blocks so that the open side is mostly blocked off, but has a gap of a few inches left in it. You should now have a rough square shape with a small opening in the front. This is the base of the furnace.

Break up the charcoal until no piece is larger than 1 inch across. Note that you need to use real wood charcoal, not barbeque briquettes. Save the powder left over from the breaking, which is called the fines. Place the fines in the base of the furnace. Fill the rest of the space on top of the fines with charcoal up to the top of the cement blocks.

Drill a hole in the flue six inches from one end. Make the hole as wide as the pipe. Stick the pipe into the hole and thread the nut onto the pipe inside the flue so that it stays in place. This pipe, called the tuyere, allows air to get into the flue.

In either of the sides next to the tuyere, cut a notch in the bottom that is 3 inches tall and 6 inches wide. To cut this notch, use a small drill bit to drill a series of holes outlining the notch, and then tap it out with a hammer.

Shred the cellulose and put it in the wheelbarrow. Mix the clay into it thoroughly. After all the cellulose is coated with clay, add water and mix it in until it all has the consistency of cold oatmeal.

Cover the flue with the clay mixture. Once it is covered to a thickness of about 1 inch, wrap the chicken wire around it to hold it in place. Twist the ends of the chicken wire together to secure it. Place the flue on top of the charcoal. The furnace is now ready for use.