Win G.

Yes, there was a typo in the wattage. Thanks for pointing that out.

Thank you all. So many great insights will definitely help me make a decision.

I am still using an IFB test kiln that I made 50 years ago from a plan from Alfred University. the interior is 8x8 an it is made from 14 IFBs with 22 gauge Kanthal wire. It fires on household current. It draws 14 amps or 5840 watts. It fires to cone 6 in about 3 hours. I would like to make another one using fiberboard instead of bricks. How thick would the fiberboard need to be? Any other ideas are welcome. TIA.