Two more are then placed on top of the first two. To finish it off, two more are mortared and set on edge
on one end, as per drawing. Let it set for 24 hours before starting any more work on it"
Next you will have to get a cement drill 1 1/2 inch, and drill one hole 1/4 inch above the base in the
center on the side. This is where the 1-inch pipe from the blower will be inserted.
You will need to get your pipe cut and threaded to the correct length. Connect a 2-inch pipe to the 1-inch
pipe; this will go to the blower.
Next, you will need to cover the firebrick on the outside. Cut 1/8 inch metal to fit to the outside and top
and weld this together, to form a box for the firebrick. Be sure to have a metal bottom already cut out to
put under the brick so the sides can be welded to it.
You can when building this go with the opening in the top, and then you need not make a door for the
front. This is the simplest way to go and I believe the best. You hang the part down through the opening
in the top. At the front, there is a small opening for the temperature probe. This is a 1/4 or 3/8 inch hole.
If you decide to build a front-loading furnace, you will need a 2-inch opening in the top of the furnace for
the gas. In addition, you will have to build a metal door for the front and line it firebrick. You now will need
to find a used Kirby vacuum cleaner blower, or any other type of high-speed blower to provide the air
for the furnace.
A shop Vacuum blower also works great. You will need to find an adjustable rheostat to control the
speed of the blower. The speed that it runs would make it impossible to light the oven. The final step is
to tap into the airline with a line from your gas supply.
The basic tools for heat-treating are the gas torch. The torch is a simple apparatus consisting of a
mixing tube into which fuel gas and a blast of air are introduced to be mixed and burned at the end of
the tube. An old vacuum cleaner can be used for the air blast.
The hose used for the various attachments for the cleaner can be used to deliver the blast of air to the
torch.