How much is enough, or when are you wasting money? I plan to build a round one using one t-rex burner. More insulation is better but there must be a point of diminishing returns. Is two inches of 2600 degree about the best compromise or is 3". If you have one you know the stuff is very expensive, but are you gaining in using less gas over the long run and increasing the life of the forge?
I also am going to use itc-100. thanks for any ideas on this.

2" of ceramic fiber is alright for general forging. itc 100 is always a good idea but if you are going to forge weld a castable refactory will serve you much better. the flux will eat right threw ceramic fiber.

I have found 3" is pretty good, I wouldn't go any more than 3 myself but others may have other opinions, but with 3" the out side won't normally get too hot to touch but that will vary with the design of the forge also.

welder19

Thanks for the replies. IT looks like I will do 14" diameter with 12" long. It seems like 12" would be the most efficient with the wool as it comes in 24" lengths I believe.
I am not sure if I will be doing welding or not at this point, so I guess that makes it hard to decide which insulation to go with.
As far as the angle of the burner, does any certian angle work better? I think the idea is to get the flame to circulate some around the interior before exiting getting more heat form the torch. thanks for any replies. kevin

the angle should come into the forge right at the top inside edge of your liner this will create a vortex and heat more uniformaly

Thanks, are you using the 2300 or the 2600 degree and 6# or 8# wool? thanks again kevin