Making Your Own Blackmithing Forge

Sat. & Sun., Dec. 29-30, 9-4PM. Two Day or One Day Class: 1st Day: Make a Propane Blacksmithing Forge; 2nd Day: Make a Bowie Hunting Knife with Your Forge. Involves cutting metal, welding ( welding done by instructor), mixing, and assembly ( see details below). Cement used is fast-drying. A propane gas delivery system will be created with black metal pipe, hose, and 3 Plus PSI propane valve. Make a knife or tomahawk on the second day. Cut a piece of heated spring steel, shape, file, and harden. Temper at home once you have filed and polished to satisfaction. 1st day (forge): $300; 2nd day(knife): $125; two day price: $400 (forge and knife). Extra cost  for a full propane tank (or bring your own) to use with your new forge on the second day of the class.

This was Willowbrook's first propane forge making class; we are now offering another class. We are limiting it to eight students. We will be working on these inside, in a heated space, during the winter months. Sign up now!

This is one of the results of our first class. Actually, this required some tweaking. We had to re-position the propane delivery pipe. The refractory needed some work as well. As this was the first class, some changes have been made to make it better. We are using a 100 percent mix of high temperature refractory. We are also using a propane gas valve that is more powerful providing a stronger and hotter flame for balckmithing.

Here you see the valve that we created in the class. A propane gas hose attached to the gas supply hooks up to the nipple. We provided the valve and hose as an afterthought for our first class, and we will provide that in subsequent classes. We won't be supplying a propane gas supply, i.e, another tank filled with propane. For an additional cost, and if you want to take the second day of knife making and use your newly made forge, we can have that on hand. The refractory we will be using is fast drying.

Close-up of the gas delivery fitting. That open 3/4 inch black metal elbow fitting stays open to allow air to flow to a very small hole that has been drilled in the smaller 1/2 inch pipe, elbow and nipple configuration. There is a 4 inch threaded black metal pipe attached to the open ended 3/4 inch elbow you see. That fits right into the welded pipe that extends into the forge shell. That 4 inch pipe merely slides in and is free floating; it can be taken out when not in use.

Here you see a successful molding of a 50/50 refractory and kitty litter mix at an insulator for the forge. This took more than a month to dry thoroughly. There were some failures with this approach. Some mixed too much water with the kitty litter and refractory making the finished product flaky and brittle. Others moved there drying refractory around too much cracking it. Doing the half and half mix saves  a lot of money, as the refractory mix is quite expensive. We offered students to come back and have their refractory fixed. The insulating wall can be patched up with pure refractory, and you will likely have to periodically "tune up" the refractory of your forge with repeated use. It should last a lifetime given the gauge of steel of the original propane tank that this forge was made from as long as you keep the refractory insulation maintained.

Made from a propane tank. The tank is prepared by initially taking the valve off. Don't do this yourself; this can be dangerous. The valve can sometimes be under extreme pressure even if you think you have bled it thoroughly. Once the valve is off you should fill the tank with water. You can cut the tank with the water in it as a safety measure against igniting any residual gas in the tank..

The next step involves cleaning off decals and labels with an angle grinder. This is purely for aesthetics.  Students prepare a number of "lugs" that holes are drilled into and serve as a way to fasten the top of the forge to the bottom. These will be welded by the instructor round the perimeter of the top open portion of the tank and around the perimeter of the larger open bottom section. The tank will be in two halves making it easy to form the refractory cement heat insulating layer on the top and bottom.

The square holes will be the openings by which you enter your metal and heat it when blacksmithing. We use a skill saw with a metal cutting blade to make two perpendicular square openings as you see.. A black metal pipe is welded in another opening that is cut as seen in the photo.  That pipe will hold the fixture for delivering propane gas. The pipe needs to be positioned in a manner that the propane gas will be delivered on the curve of the refractory lined interior of this tank.. Gas will swirl once delivered, and the objective is to have the ignited propane delivered inside form a vortex which will achieve the desired heat for heating metal so that it can be cut, shaped and forge welded. The gas must be delivered at 3 PSI or more to achieve the needed heat for blacksmithing.

Actually, this pipe seen in the photo needs to be slightly re-positioned as you can see that much of the flame delivered would escape from the square hole on the left, which is one of the entry points for your blacksmithing project. The flame would largely exit through that hole rather than starting on its way to creating the desirable vortex.

Here instructor Adriaan Gerber welds lugs and the metal pipe gas delivery pipe to the cut propane tank we are using as our shell. We are also welding horseshoes to the bottom of these tanks to raise it off the ground for easier use in the future, and it makes for an interesting look. One might mount their finished forge on a heavy metal table to bring it to a more desirable working height ( see the homemade metal table created for the welding rig).

We painted each of these forges with high temperature black paint.

Here you see the top and bottom sections of the forge with the welded lugs that will later be fitted with nuts and bolts to close during use.

Here we see the painted forge with the welded horseshoe legs, lugs, and pipe.

For our first class we used a 50/50 mix of high clay content kitty litter and refractory cement rated at 3000 degrees Fahrenheit.

Every student created a mold to set the refractory in and preserve a center void with card board and duck tape but other materials could be used. A piece of old black metal stove pipe or a piece of Sana Tube could also be used to keep the refractory out of the center until it dries, and this would create a more uniform and smooth surface to the refractory.  The cardboard could be burned out on the initial firing of the forge; in fact, this is recommended as taking it out once the cement is dry may result in damage to your desired form.

The tank is first filled with refractory to a depth of 2 inches. This is your fire pan. The mold is formed on that in addition to creating forms to the two openings for blacksmithing.

This is the cardboard form that refractory will be poured around creating insulated walls when it dries for the forge. See the two cardboard constructions which preserve the openings for blacksmithing.

A birds eye view of the constructed card board form. This is ready for the refractory.

Here we test the gas delivery device we have devised. We will drill and fit all the pieces

The larger 2 inch in diameter pipe is the piece that is welded into the shell of the propane tank used for the forge. the smaller pipe inside is the propane gas delivery pipe, and the flame comes out of that.

Here we see the lids for the forge with the refractory in it as well.