BUILDING A GAS HEAT TREAT FURNACE

Building a small heat-treat furnace for the shop. This furnace is made from standard firebrick, 2 1/2 x 4
1/2 x 8 inches. Firebrick does vary in size, so the size shown in the drawing may have to be changed to
fit your needs. Another style of furnace is where the main opening is at the top, and the part hangs down
on the inside. This seems to give a more uniform heating.

A-Gas/Air outlet; B-Furnace opening; C-Side view; D-Opening for temperature sensor; E-Blower;
F-Gas intake; G-Heat sensor pipe; H-Heat sensor opening;

You will need eight firebricks to make this. When completed you will have a furnace with an inside size
of 4 1/2 x 3 x 8 inches. This size will handle just about any job in the shop.

The firebrick is mortared together with the cement used in fireplaces, and it should not be any problem
to get from any business that sells fireplaces or wood burning stoves. The brick is placed 2, flat side by
side, mortared, and then one brick on each side is stood on edge, (see drawing) mortared to the two
laying flat.

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