that box there is 24" deep 40" tall 26" wide the only problem i have had is i got the box cherry red on the back side a few times. there is no fiberglass in it either it is straight metal..

if you adjust the intake tube you can keep the heat to 400/450 no problem. i built it just to do wheels in.. i have had it at 700 for an hour for ceramic but i would not do much of it in there..

i got 3 ovens the biggest being 8'x8'x8' i run 2 200k heaters in it
i got another oven 24'long 18'wide and 8' high i need to run some elemnts in it it will be electric and gas .. the gas will get it to the temp i need then the electric will kick in and keep it there...

well back to powdering i go .. i got part's in the oven as we speak