I have struggled long enough when working with 10 inch blades doing the old 'in-out' when trying to get equal heat over the entire length.
I have a 12 inch forge, but once it's lined, the working heat zone is much diminished and you have to work the blade in and out for an eternity, it seems, to get everything even, and there always seems to be a high risk of overheating some things.
A 12" is alright for smaller blades.
So, without vastly creating a much larger heating volume, I took a 12" pipe, cut it in 1/2 lengthwise and welded in 6 inch webs.After 2" of ceramic blanket, this leave a 14" effective heat zone.
As well, there's one layer of 1" blanket on the bottom and then four inches of clay cat littler to catch flux.
The top two inches is ceramic blanket with a heavy coat of Satanite.
First picture is of the forge as built.
Second picture is of the forge after I had it up to welding temp for 20 minutes! :eek: