Having the ability to bring steel to a temperature high enough to change its physical state is essential in knifemaking / bladesmithing. I am going to show you how to build a forge that is simple, safe, and effective. There are countless gas forge builds documented on the internet, I want to set this one apart by showing exactly where I got the materials and how they go together to result in a forge that work will work for you too!
Gas v Charcoal
I have made both gas and charcoal forges/ furnaces. Both types are relatively simple to build, but for my needs, a propane fueled forge is the only option. I live in a residential area. I have neighbors on all four sides of my shop within 100 ft. Using gas lets me run a simple setup inside my garage with minimal fire hazard. Propane is much more space efficient and cost effective in my situation. However, if you live in an more rural area, you may want to consider using coal.
Step 1: Materials
Firebrick is different that ordinary red brick because of its ability to withstand high heat without breaking down. Shipping brick is not exactly cost effective, so only order it as a last resort. Search your area for a distributor. Google Maps makes this easy, search keyword phrases like “Firebrick”, “Fireplace” or “Refractory”. Call ahead to your selected business to make sure they have firebrick and what sizes they offer. The ones I used for this forge are 2 1/2x4x9”.
I also found some thinner bricks at Tractor Supply Co. They are 1 1/4” thick and I used them on the top and bottom of the forge to insulate it, but if this is all you have access to, try wiring 4 of them together for the proper thickness.
The burner is the assembly that applies heat to the forge. You can find plans and parts online to build high pressure high heat propane burners. To make it simple, I suggest you buy the Bernzomatic Hose Torch Propane Kit. Home depot carries them in store for about 65$.
You can also click here to get them from amazon.
The brass torch tips that screw onto the tops of bottles do not get nearly as hot as the bernzomatic torch. Also, if you do not already have a torch, investing in a quality model will add an extremely useful piece of equipment to your shop.
To run the torch off of a 20 lb propane tank, you are going to need a hose adapter. I got an 8' hose with the proper fittings from the camping section of walmart. You may be able to buy the female to male fitting on its own, but I chose the hose adapter because it added an additional 8' into my setup.