How to make a Homemade Mini Forge
Making a homemade Mini Forge (sometimes called a firebrick forge) can be a great way to make jewelry and other objects at home, or to heat and bend small pieces of metal to make something like a knife. You can also use a Mini Forge to make and stamp coins.
Project Warning: This project deals with combustibles and extreme temperatures. This Mini Forge can reach temperatures of over 2500° F (1370° C). Extreme caution should be taken and adult supervision is mandatory. Care should always be taken not to overheat the torch or forge. There is a serious risk of injury and burns if not used correctly. If you have any doubt about your ability to do this project, please do not do it.
Also, using a torch in this manner, while safe, will likely void the manufacturer’s warranty and may result in decreased life of the nozzle. You have been warned.
Building the Mini Forge
Building the Mini Forge is quite simple and only requires a few parts. You can get them all at your local hardware store or from Amazon.com. See the PDF and Sketchup Plans for all the dimensions. You’re going to need a firebrick (this is not a regular clay brick), a torch with locking trigger and tank, a two foot section of aluminum angle, and four 6 inch bolts, with nuts and washers.
When purchasing the firebrick, make sure it is rated to at least 2600° F (most are) as we’re going to generate a lot of heat. Using an under-rated block will cause fracturing that could lead to burns and/or starting a shop fire.
The first step is to cut the firebrick into two equal halves. This can be done in any number of ways. I chose to use my compound miter saw because it makes for a very clean finish.. If you don’t have one of those you can use a hacksaw, a bandsaw, or drywall saw.
The firebrick is made out of ceramic and silica so it won’t damage your blade and will cut easier than most softwoods (regular bricks are made out of sand and clay). Just don’t cut it too fast or you could fracture the brick. It’s actually somewhat fragile and too much pressure can be bad news for your Mini Forge (the speed in the video is actual speed, not sped up or slowed down).
Step two is to drill the holes in the forge. I used a 2 inch hole saw bit and my drill press. Again, I did this because I felt like it made the cleanest cut. You could also use a paddle bit and a handsaw if that’s all you have.
Be sure to put a sacrificial board under the brick so that you don’t get a bunch of “blow out” when the bit exits the backside of the brick. This is especially import if you use a paddle bit.
You’re going to need a hole that is the same size as the nozzle of your torch in the side of the brick. That hole of course intersects with the larger one in its center. The exact dimensions are in the PDF and Sketchup plan files.
Step three is to make the angle brackets. I used aluminum because it is lightweight and has a little give to it which helps with the softness of the firebrick, but you could use steel if that’s what you already have, but do not use wood or plastic! Cut the section of 24 inch angle into four 6 inch sections. You can do this with a cut-off wheel, metal cutting rotary saw, handheld hacksaw, or a reciprocating saw (sawzall).
Drill a hole at both ends of each of the angle sections (on the same face) using a drill-bit that matches the diameter of the 6 inch bolts that you purchased. It’s important that these are centered so that they spread the clamping force evenly.
Putting the Mini Forge Together
Assembling the Mini Forge is incredibly simple. On a flat surface place both halves of the firebrick together. Then just lay the six inch sections of angle on the two halves of the firebrick, slide the bolts through and tighten them up snuggly. Again, be very careful not to over-tighten the bolts as the brick will fracture if you do.
Take care to make sure the hole for your torch is on the left or the right side of the completed firebrick. Which side is up to your preference, but if it winds up on the top or the bottom you’ll have to take it all apart.
Using the Mini Forge
The Mini Forge can be quite the cool tool around your shop, and its certain to attract questions from your friends and family who see it. It’s always a neat discussion piece around my shop. Using the Mini Forge is as simple as placing the nozzle of your torch into the small inlet hole and firing it up. It only takes a few seconds for the inside of the forge to reach operating temperature (in the video I say “minutes”, but I meant seconds). I highly recommend you get some long handle pliers to hold your objects with so that you can keep your fingers and clothing far away from the Mini Forge. I use some 12 inch needle nose pliers I got from Amazon for $5. Don’t spend a lot of money because you’ll likely destroy them pretty quickly heating items up with them at some point anyway.
If you make the Mini Forge be sure to send me some pictures of it!
To make our Mini Forge, you’re going to need a firebrick, four 5/16 by 6 inch bolts, 8 fender washers, 4 nylon lock nuts, a section of aluminum angle, and a propane torch, which next the forge itself is the 2nd most important item we’ll need.
To get started we need to half our firebrick. Find the center point and then make a tick mark. Then using a square draw a line down the exact center of the brick. Next using my compound miter saw, I halved the brick. Just go slow and it slices it like butter and gives a super clean cut.
Now over at the drill press, use a 2″ hole saw and drill out the center of one of the bricks. Again, just go slow and it works great! If the center gets stick in your bit a few taps should set it free. We’ll finish off the brick by drilling a 5/16″ hole in the side of it that connects to the large center hole. When you’re done, you should have a solid brick and a brick with two holes in it that will become our fire chamber.
Take the aluminum angle and measure off four sick inch sections, and using a cutting tool cut them out. At the end of each aluminum section droll a 5/16″ hole. When finished the completed sections should have two holes on one side and look like this. And now it’s time to assemble all the pieces!
Take the aluminum sections and run the bolts through them with washers. Then we’ll place them on the bricks. Be sure that the side hole we drilled is situated on the left side, towards the center of the bricks and then install the next section of aluminum angle. Now go ahead and install the top straps, along with fender washers and nylon lock nuts and hand tighten them.
Using a 1/2″ socket wrench we now need to tighten up the straps. We want the straps to be secure, but do not over tighten them as doing so will fracture the bricks. And this what our completed mini forge looks like!
I sat the mini forge on top of pan, inserted the propane torch, and fired it up! Within a few seconds it was glowing red hot inside the fire chamber and about a minute later, we’re ready to start using it!
Using some long pliers, I took this scrap metal I had and placed it in the mini forge. It took about about a minute and it was glowing red hot! Well in future videos I’ll show you how to use this forge to make all kinds of cool things. If you have a request, leave it in the comments! And if you like this video, please like and subscribe to my channel on YouTube!
By popular request, here’s where to get the firebrick I used. It’s a seller on Amazon.com.
AMACO Insulating Firebrick – 9 x 4 1/2 x 2 1/2 inches