Originally posted by Michael Pfander:
Karl: Care to explain vertical forge. I thought they were all vertical, just a matter if the flame is on top, bottom, or both.
MAP
So many of these commercial forges are designed to simply heat the steel by direct line-of-contact with the flame. They're everywhere.
I hate them.
When using that type of forge, the area of steel heated by the flame is very small. This acts to inconsistently heat things making heat treatment very undependable.
The 'vertical forge' is an upright cylinder with the flame entering at the bottom.
The forge body is heavily insulated.
When the entire forge mass becomes heated it heats the steel by thermal mass radiation is is very regular over a large area.
I've made four different forges over time - an 8", two 12" and the one I now use which is a 12" cut lengthwise and an extra 6" web welded in.
The heat zone is at the top. I effectively have 18" of heat zone which is very desirable when heat treating large blades or forging billets of Damascus.
They are easily less than the cost of commercially made forges and simple to build.
Some scrap tubing and a blower with some plumbing pipe.