Blacksmith propane gas forge using a T-Rex burner.
Many thanks to Jesus Hernandez, Rex Price and Ron Reil for the valuable information on their web pages from which this forge was inspired and designed.

Easily reached welding temperature at 10 psi, but runs comfortably at 5 psi, even lower. 



I don't have a bending press, so I used a grinding wheel on my circular saw to score first, then heat and bend. I used a straight edge guide to keep the line straight. Careful not to score too deep as it will weaken the bend.

The burner holder is a piece of square tube with 2 screws per side so I could easily aim the burner in any direction.

I used a thin layer of Kiln cement to glue the first layer of Kaowool to the shell, but I probably didn't need it. The Kaowool seems to stand up on its own.

The ceramic fire brick sides are to protect the Kaowool from being poked by the iron. Kaowool is like cotton candy. The removable shelf catches corrosive welding flux (4 parts Borax, 1 part Boric Acid) and will not eat through the silicon carbide. It slides out for easy reconditioning.

Initially I had welded steel posts to hold the ceramic posts in place, but removed them as they were acting as heat sinks transferring a lot of heat to the shell. I filled the center post holes with Kaowool to eliminate any air gaps, and surrounded them in Kaowool instead. This works much better.

The ceramic shelves were cut with a masonry cut-off wheel attached to a circular saw

The direction of the flame is slightly offset both side to side and front to back to reduce any back pressure from the burning gas as it expands to 8 times in volume. This creates a swirling motion and lets the exhaust gases efficiently exit the chamber. The flame should come out of the openings seeking oxygen, thus creating a 'reducing' atmosphere inside the chamber (starved of oxygen). This is the key to forge welding and avoiding oxidation. 
The burner tip is recessed 1 inch back from the chamber ceiling to protect it from the heat. Also, it's very important to correctly size the chamber to the burner. See more about chamber sizing on Hybridburners web site.  

I coated the chamber with ITC-100 using a brush, no need to spray. ITC-100 is a very high infrared (IR) reflective ceramic coating that increases the heat retaining efficiency of high temperature furnaces. It also helps to save fuel and quickly achieve high temperatures. Also ITC-100 seals the Kaowool by creating by a hard surface that prevents the formation of dust. 


I went ahead and used the ITC-296A top coat over the ITC-100. It is a high purity fine grain coating that results in a smooth surface and reduces any impurities building up and sticking to the lining. Also it greatly increases the life of the lining.  

I Coated the inside of the fire bricks also. These are soft fire bricks, but the top ones cracked due to temperature differences, so I replaced them with hard bricks.
I use a high quality Harris 425-50 regulator with a splitter tee for my hand torch.

The purpose of the operational valve is to save fuel while you're at the anvil. When the steel is hot and is removed from the forge, the operational valve gets closed. A small amount of gas then flows thru the needle valve to keep a very small flame alive. Basically it's a pilot light. Then when you put the steel back into the forge the operational valve gets opened and the forge returns to normal burning. This is a huge fuel saver.  View fittings and valve details...

I  use a quick-connect to for the gas hose. It makes the forge very portable.











 










I spent roughly $600 on materials back in 2007.  

Materials from: 

T-Rex burner:  www.hybridburners.com

Kaowool and ITC-100, ITC-296:  Dempsey's Forge  - www.anvilfire.com

Ceramic shelf: Laguna Clay Company - www.lagunaclay.com

Valves :  www.valvestore.com