Some coal forge details
These photos illustrate the forge that’s in the Sahuaro Ranch blacksmith shop. It’s the original forge made as a wood plank box and filled with brick and earth. The ‘tuyere’, or firepot is simply a large diameter iron pipe the runs underneath the width of the box with fittings on each end.
On one end, the fitting has a wooden paddle which was used to control the air pressure that comes out the hole in the ‘firepot’.