View Full Version : Building Your Own Gas Forge

05-06-2004, 11:44 PM
I have been reading some threads from people wanting to buildtheir own forge. Well, I do not want to waste this opportunity to recommend all of you guys to buy the book "Gas Burners for Forges, Furnaces, and Kilns" by Mike Porter. This book is all you need. It is so amazing that I bought it because I wanted to have more tools to work on my metal sculptures. However, now I am more interested in the book and what I am buiding than the use that I am going to give it. It is a most have book. The only regret that I have so far is that my copy is already dirty from too much use, I am looking forward a second edition just to keep it in my library. This is the link for yu to buy it: http://www.amazon.com/exec/obidos/ASIN/1879535203/qid=1083900984/sr=2-1/ref=sr_2_1/002-0082153-2269647
Alfredo Alamo

05-07-2004, 04:07 PM
About 15 years ago, I built several gas forges for myself and friends, which are still in daily use. Sandia National Labs had a blacksmith working for them at the time named Robb Gunter, who developed a naturally aspirated design. The initial plan was very involved and took quite a bit of time to build. It was also fickle about ambient temperature, altitude, etc., but I built a couple and used them for a while. Over time, I figured out some of the important variables and started focusing on them. I eventually settled on using a rammable clay from AP Green for the floor and highly reflective insul board for the body of the forge. The clay is a heat sink until it gets hot but it also helps put BTU's in a big cold piece of steel. The insul board is rated at 2600 degrees and serves to reflect or contain the heat inside the box. The box was 16 ga sheet sheared and bent to make a square form with a rear stack. There is a hinged front door to retain the heat, which can be pivoted up to allow putting a piece inside or a long bar under the door. There is also a hole in the back to allow a heat on the center of a bar.

You can make a box any convenient size to fit your type of work. Many people use old propane bottles and Kaowool, which is also good. The wool won't stand much abuse but it's cheap and easily replaced. I use a small 60 cfm squirrel cage fan from Grainger for a blower and run the mix pipe over the exhaust so I get a little preheat before ignition in the box. The control orifice is just a simple gate valve placed after the blower and the burner is plain 3/4 pipe. This forge will run about 80 hrs on a 100 lb propane tank at 4 lbs pressure and will melt steel if placed directly under the burner.

06-24-2004, 11:45 PM
I also built a small propane forge that I use to melt silver and to heat iron rods for the anvil. Its a basic forge made of k23 and k26 brick, lined with itc100 and fired with a hybridburner. Whereas HW built his forges with blowers, the one shown at the website below is normally aspirated.


I've since lined it with stainless steel sheet for a cleaner look.

You may be only interested in the book now, but I recommend designing and building your own because it is way too fun, and because you WILL find uses for it afterwards...including roasting marshmallows. I've even fired small ceramic pieces with it. My brother has used it to melt lead and make fishing sinkers. The possibilities are endless.

My next fire box will be either a larger propane forge or a raku kiln, but that a ways off.

06-25-2004, 12:05 AM
I work on crematories and we use a material called Express-30 it is a 3000 degree material that is very durable for the floor and can be formed into shapes. On the walls we use a ceramic fiber module that is rated to 2600 degrees we have found that these last longer than the 2600 degree insulator bricks. There is also a material called Thermbond that can be formed but it sets up in 30 minutes so you have to work fast and not do large areas but a forge would be farrely small.

07-01-2004, 11:04 AM
Where can a person get this material (Thermbond)??

07-01-2004, 09:11 PM
CoCowboy try: http://www.refractech.com/thermobond.htm

07-26-2004, 09:07 PM
Thanks for the tip on the book I bought i**** a great looking book very informative

08-01-2004, 06:53 PM
I saw a big bbq-pit looking thing out behind a mortuary the other day. I'm guessing they don't use it for cookouts.