I am in the process of building a hot box. I bought the thermostat from Bingham projects. Not sure what the high temp is before the thermostat shuts off. What is a good insulation to use inside of the box that can handle the heat.
Thanks for you help.

I never insulated the interior of the box, I lined all surfaces with heavy duty foil. Then gave a light coat of spray foam to the outside, not enough to make it bulky, about 1/2". Seems to hold the heat well and the Bingham thermostat cycled as needed. I use a different method now, but the box performed very well too.  Good luck!

My heat box is always in the way, so next one will be 1/2 or 3/4 " foil faced both sides foam made into a folding box with no bottom and the heat source on a piece plywood on top. Set it on concrete floor and put the lid on and go...

Then I can take it down and store it easy. Mine takes up waaay too much shop space.

You really don't need insulation on those things, but the foil back foam holds up well under heat until you tear it up... I used 4 - 200 watt light bulbs on mine and have an adjustable thermostat. The old binghams thermostat shuts down at 160 degrees i believe..... i only use mine in winter for curing riser block lay ups.

Foam board insulation is cheap and easy to use. One time I made a hotbox with just foam board insulation - no wood. I taped it all together with metal tape.

I used this but my box is big and deep

https://www.lowes.com/pd/Reflectix-R-21-50-sq-ft-Unfaced-Reflective-Roll-Insulation-24-in-W-x-25-ft-L/3011904

Quote from: Kirkll on January 20, 2024, 03:44:04 PM
You really don't need insulation on those things, but the foil back foam holds up well under heat until you tear it up... I used 4 - 200 watt light bulbs on mine and have an adjustable thermostat. The old binghams thermostat shuts down at 160 degrees i believe..... i only use mine in winter for curing riser block lay ups.

I think it is 185 to 150

Quote from: Mad Max on January 20, 2024, 05:20:11 PM

Quote from: Kirkll on January 20, 2024, 03:44:04 PM
You really don't need insulation on those things, but the foil back foam holds up well under heat until you tear it up... I used 4 - 200 watt light bulbs on mine and have an adjustable thermostat. The old binghams thermostat shuts down at 160 degrees i believe..... i only use mine in winter for curing riser block lay ups.

I think it is 185 to 150

You know something.... you may be right about those Binghams thromotats being 180-185 shut off. I had my temp set at 160 with my adjustable set up.

Mine is mildly foil lined (half torn off by use). And I've got a temp controller set on mine for 150 at the height of the glue up. Mine does have the binghams temp controller thing on it up top- but I noticed it was kicking the bulbs off at 110-114° at the height of the glue up. So I added the ink bird for a few reasons, one to bypass that switch.

Soon I plan to add a fan- just to ensure the heats distributed.

Mine is insulated with foil lined foam, foil facing in. Never had any issues. I do recommend a fan along with Ceramic tiles to protect the form from any Hotspot. With those additions I only needed 2 bulbs on to maintain temp.