After building my small coal fired forge, I was concerned about obtaining a continuing supply of coal for its operation. Coal is not a common commodity in Tucson, Arizona! So I decided to build a small propane fired forge. I wanted it to be small, cheap, quick, and easy to make. I decided to utilize the well known Ron Reil burner design. Plans are available from his web site. I used the modified design which uses a pipe nipple screwed into the back of the burner to secure the propane jet hole tube. I drilled this hole to .042" diameter. I post this information and design to help others interested in making such a small forge. No detailed plans are necessary since nothing is critical and all is based on the size of the fire bricks.
The forge itself is merely constructed of 8 fire bricks modified as shown in the images below (7 will work).
The high temp fire bricks that I selected to use are 9" x 4 1/2" x 2 1/2" in size, very light weight, and easily cut or carved. The images below show how I stacked the bricks to form the forge body. The back wall brick was notched as shown and the two side wall bricks were cut off to fit the notches. I cut the bricks with a hacksaw. The fire brick joints can be "fitted" by rubbing the edges to be joined against each other - like ancient stone workers did. This will wear them together for a good tight fit. The small item at the front of the forge opening is a 4" shelf support turned on its side. This helps to hold heat inside the forge.
Note:
After communicating with Ron Reil and at his suggestion, I cut an opening in the back fire brick. This will allow longer stock heating and provides another vent for the hot exhaust gases. An excellent suggestion! The cut was made with a hacksaw and smoothed with an old wood rasp. The modified fire brick may be seen here.
This image shows the fire bricks joined and ready for the roof bricks. This image was made before I modified the rear fire brick. Notice the hole in the right side brick. This hole is for the burner tip.
This image shows the beginning of drilling the burner hole in the fire brick. This drilling was done with a custom made tube drill. You could pay to have this made ....or................................
....make your own from an old length of 3/4" pipe. The end was filed with four notches to do the cutting in the soft fire brick. I merely rotated the pipe as I slowly pushed it through the fire brick. This will provide a nice clean burner hole in the center of the brick.
You can better see the finished hole in this image of the stacked fire bricks.
The image at the right shows the burner inserted through this hole. This was the test firing to see if my forge design would even work. I will eventually weld up an angle iron frame to hold everything in position and weld a steel burner support. In this image it is just held up by a stack of fire brick cut offs. These fire brick really insulate. I was able to place my hand on the top brick after taking this image!
Needless to say, the forge does work - as seen here with a length of scrap steel. I tested the forge and burner and found it to work best at 5-10 psi of propane.
Here is what everything looked like during the test burn. I already had the propane tank and high pressure regulator left over from my glassblowing days (another reason to make a propane forge).
The whole forge will be mounted on a steel plate which will go atop a steel base I already have in my junk pile. The stand illustrated was only for the test burn.
The below two images show the completed forge. Everything is welded to a 1/16" thick steel platform which could be moved, if desired. The upright steel angles were welded to form a "box" for the fire bricks. This will keep them from shifting as they crack with use or if I accidently hit one while heating steel. The image on the right shows the burner as completed.
Note:
I tried the below modifications and really determined them to be unnecessary. They are posted here for your information.
If you will look closely at the above image, you will see the threaded pipe length sticking out of the burner air inlet. This was done for further experimentation. I wanted to add a foot switch activated blower for a quick "heat boost" when needed.
This image shows the temporary hookup for testing the blower. The propane feed tubing is braided stainless steel covered. The blower plugs into a foot switch (on only when depressed). The large valve serves as a choke for the standard burner (no blower) and as a control for the forced air when the blower is running. This valve can be set for optimum burning without the blower running for normal use. When the blower is activated, there will still be a good blast with the valve partially open. Closing the valve will allow full blast force.
Here is a closeup view of the burner showing the air and propane feeds.
The blower is a standard type found at scrap yards.
The valve is left open at the top to allow air intake when operating in normal mode.
Well, that's it until I weld up permanent blower and forge supports.