Well, the idea of 3" of insulation was to reduce the ID of forge to around 6", but thinking a bit I suspect 2 layers of 1" insulation will actually wind up being pretty close to 6", maybe 7" and that's just fine.Why 3" of ceramic fiber??
I can't image that much mass in a forge. Remember, I've only the the "Baking Soda" (Arm & hammer) type of power hammer so won't be working with anything that large. My arms 'n shoulders won't take that much stress.same 15lb billet
To some extent I'm thinking of the thicker insulation (now thinking 2") to protect the thin metal shell of the forge body from burn-out. Should I put a thin layer of refractory cement slurry that is thinned to down to latex paint type consistency brushed over the first layer of fiber as if just "painting" it to hold the fibers tight before placing the second layer in? OR, best to place both layers in dry before starting the "painting" of the refractory cement slurry over the inside to seal all the fibers really good?
OK, I'll plan to leave the firebricks out and use just the ceramic fiber and refractory cement for lining. Perhaps later I'll coat with ITC-100 if I decided I need it. Trying to save a bit of money (just ordered a new ham radio), so far I've only ordered the Ceramic fibers, had all the rest of stuff on hand.
Thanks again for all the help keeping me on the right track.