I’m planning on making a custom oven in the near future, and have been looking at insulation, and I found some high-temp fiberglass insulation at mcmastercarr.com
Here’s the specs:
• Temperature Range: 0° to 1000° F
• Heat Flow Rate: 0.22 Btu/hr. x in./sq. ft. @75° F
• Color: Light tan
These lightweight blankets provide high temperature insulation. Made of glass fibers bonded with a resin, they can be layered up to a thickness of 6″ for increased thermal efficiency. Use a razor knife to cut and install using pins or studs. Use indoors, or add a jacket (see pages 3312-3313 ) for outdoor use. Perfect for use on boilers and vessels. Density is 2.4 lbs./cu. ft. Meet ASTM E-84 for flame and smoke.
a 24″x96″ blanket 2″ thick runs ~$24 + s/h, which i think is very reasonable.