to shut the air down quite a bit. If you tried to use the full amount of air, it would blow out the flame.
When you are ready to start the furnace, hook up the gas, check for leaks with soap, and if OK, you are
ready to fire up.
NOTE - It is important to do things at first very carefully to prevent an accident. This is the way I have my
furnace set up, and have had no problems. I have no control over what is done by other people, and
cannot accept responsibility for what some other person does. If you build a gas furnace, you are on
your own. Check it outside of the building for safety's sake.
Turn on the air, and close down the valve until there is almost no flow through the pipe. Now take a
butane torch and light it. Open the main valve on the gas tank.
BE SURE THAT THE SMALL ADJUSTING VALVE IS CLOSED ALL THE WAY.
Holding the lit torch over the opening, slowly turn on the gas. In a few seconds it should light. There
probably wont be much flame, so slowly open the air valve/gas valve until the furnace has a "roar" to it.
Don't open the air valve to much as you need a slow heat. Adjust the fuel so that you get 3 to 4 inches of
flame from the top. Let it heat up for a few minutes to dry out, and then it is ready to use.
Once it has cooled down, it can be moved back in the shop. This furnace can be changed to where it is
front loading, made larger or altered for what ever is needed.
This furnace is very fast. Normally it takes only 10 to 15 minutes to get to operating temperature. I find
that hanging the knife parts down from the top will cause even heating. You can use two bricks to close
down the opening more to confine the heat better. When through heat-treating, close the top up with the
bricks, and let cool down to tempering temperature.
This furnace works great with 01 and other tool steels. It can be used for forging steel as well.