I built this one brick forge because lately I have been involved some with metal working (most noteworthy was my homemade Rabbit Wringer). As a metalworker, I need work. However, I still have both eyes and I haven’t burned anything down so I am happy with my results.
I started my needing to make some tools for my new foundry, and decided to “blacksmith” some from some bar steel I bought. My propane torch was used to heat everything up, but that was slow going and not very satisfactory.
Luckily I remembered a book I bought a few years ago – Wayne Goddard’s $50 Knife Shop, Revised. In this book Mr. Goddard gives some advice to beginning knife makers on both the basics of metalwork, knifemaking, and shop tools. (IMHO this book is worth buying for the shop advice even if you never want to make a knife.) There is a chapter on how to make a small and very inexpensive forge for heating, tempering, or annealing small bits of metal. Of course I had to make one.
The basis of the forge is a single soft firebrick.
I found one at the local ceramic supply store for $5.00. Soft firebrick is very light and crumbly – almost like an airy Styrofoam, that is what makes it perfect for this use.
All you need to do is to take an old 1 inch spade bit and drill out the center of the brick along its longest axis. Next turn the brick on its side and drill a hole halfway through the brick until you meet the hole you just drilled.
If you take a mapgas or propane torch and place it just outside the hole in the side of the brick and allow the flames to lap around the inside of the brick the center of the forge will get very hot. It will heat any metal placed inside the long drilled out hole to cherry red in just a few minutes.
The only problem being is that the porous structure of the brick tends to hold moisture and if you get it hot very quickly it can crack. In his book, Mr. Goddard suggests wrapping iron wire around the brick to hold it in place even if it cracks. I went a little overboard since I just got my welder. I welded up an angle iron box, inserted the brick, and then welded it shut. It was the first thing I welded that actually looked like a decent weld.
This forge works great for small pieces and I have used it a lot with no problems. It’s a great piece of equipment to have in your shop.