i am worknig on making a new forge right now.
it is gongi to made out of wood with a plywood table on it with a firepot resting in a hole cut in the plywood surrounded by sheetmetal.
the entire framework of the forge will be make of lumber.
what do y'all think?

Son

plywood has glue

Ive seen historic photos of wooden framed refractory lined forges
they were solid wood of fairly decent dimension.
What I gather to be important is a decent insulative barrier
sheetmetal wont protect the wood from sustained heat, it will transfer the heat nicely, char the wood, and eventually when the charing progresses enough that oxygen can get to it, catch fire.

But the glue off gassing from the plywood, just isnt good for you, and will delam the plywood.

is it outside?
how long is it supposed to last?
are you building it under a water tank?

it can be done, but use deep beds of sand, lots of firebrick, perlite ect.
either highly insulative or a thermal mass so large that your unlikely to heat it up to the point it can damage the wood within a typical work session

I have seen 2 forges out of wood but both had stone dust and fire bricks on top of the wood and 1 with fire clay or such morter joints. The wood was not plywood but ruf-cut 2" by 6". The 1 with just stone dust & firebricks allowed bricks to be removed and then the stone dust put in buckets now forge is light and easy to move. hope this helpd some.

I really suggest metal but if you have to use wood then use something more than just sheet metal, get a sheet of wonder board or dura rock, the stuff that goes between the brick and the wall when you put in a wood stove.
Most building supply stores carry it, it looks like cement sheetrock, it's a good insulator.

welder19

One of our members has a Viking Era forge made from wood. Uses sand for insulation.
Travis

a viking age forge.
do you know who it is? and who made it?

Son

The wood forges I have seen all have 3" to 6" inches of insulating sand,dirt, and/or ash.
I think you are a risk building a wood forge with less than that.

By the way even some commercial, high volume blacksmith shops used wooden forges where bricks and iron were very expensive. The blacksmith shop at the "Amercian Eagle" mine at Victor Colorado has a wooden forge.