The air blast tends to blow the main flame so far away from the end of the mixing tube that it will mix with
so much outside air that it will no longer be a combustible mixture and will be snuffed out. This annular
ring of low velocity flame surrounding the outlet of the mixing tube will keep the main flame ignited unless
so strong an air blast is used that the entire flame is blown away from the end of the mixing tube.
When you start up the burner, shut off the gas until you have the air adjusted, and then slowly turn on the
gas, while holding a lit Butane torch over the opening of the furnace. It is best to reduce the air blast until
the gas is ignited and then slowly open it until the desired flame is obtained. The flame should burn with
a firm blue center cone, and the hottest spot will be at the tip of the blue cone. A yellow flame is not as
hot and is very sooty. After the bricks of the furnace have become well heated, the air blast may be
opened a little farther, and the blast will thus be increased.
The flame from this torch is very hot and will heat steel to a white heat for forging, but it is not hot enough
for welding, however a supply of oxygen for the air intake will increase the temperature.
Get large enough cement drill to drill a hole through the firebrick about 2 inches from the top. The heat
sensor will fit in there. I find a short length of iron pipe that is large enough on the ID to allow the sensor
to fit inside. This pipe is then mortared in place. See Drawing.
A High Temperature gauge can be purchase from an industrial supply dealer. If you can find one, a
2000-degree gauge is best.
In the air intake pipe, (A) you will need some kind of manually controlled valve. You will have to be able