A brick forge is one of the oldest known tools for blacksmithing. A brick forge can be built practically any shape or size to fit the blacksmith's needs. This may require some masonry skills, depending on how the smith chooses to build his or her forge. A foundation, a chimney, and a heating chamber are all required when building a brick forge that will handle very high levels of heat.
After determining how big to design the brick forge, the first thing to do is, dig a pit large enough for the foundation. In this pit, also dig a spot to install the pipes and heating system under the heart of the brick forge. It is a good idea to leave a gap or a ditch around the foundation to store unused coal. This will keep the coal dry and ready to use as when needed. The heating system can be done fairly cheap at a local hardware store. Place a T-Joint pipe in the pit, with the top of the T running vertical (place a cap on the side pointing down at the ground) and the base of the T running horizontally. Attach a fan to the base of the T-Joint, preferably a Squirrel cage fan.
Now it is time to lay the foundation. When poring the foundation, leave a hole for the heating system pipe and open space around the heating system for easy access. Using rebar to reinforce the foundation as it is laid is always a good idea, but the foundation will hold just fine without it. The hole left over the pipe in the foundation is to be covered with a piece of grated metal. This allows the fan to blow air through the T-Joint pipe and circulate heat from the fire all around the inside of the brick forge.
Now comes the part where those masonry skills will come in handy. The chimney will be started with a fresh layer of mason. Lay down a row of fire brick and make sure to mason in between each brick generously. This is very important, because cracks or spacing between bricks will allow heat to escape from the brick forge. The chimney design can be as basic or unique as desired, it really makes no difference in performance. The most important thing is just sealing the chimney up good and tight. Leave an opening in the front of the chimney to do the blacksmithing or metal work. Lastly an anvil and forge table will be needed for the brick forge. It is important to put the forge table on a foundation as well. The anvil should be on a foundation along with being anchored down using rebar hooks or brick anchors.