Kiln liner

[pasbuild]

Can rubber roofing be used as a kiln liner?

[HORSELOGGER]

When I built my kiln chamber, I paid these 2 guys to come out and spray expanding urethane foam, 4 inches thick ( r 28 ) when looking at all costs, including my labor, it was much more cost effective to have this done than buy all the insul board and caulk and plywood and kiln paint, etc....
It has held up well , been in since last summer.

[Don_Lewis]

Foam is a great way to go but to answer your question, yes, roofing rubber stands up very well in a kiln environment

[ElectricAl]

HorseLogger,

What was your installed price per sq foot?

We talked to an installer that quoted $1 per sq ft. for a soybean based expanding foam. Another installer that uses a petroleum based product quoted $2.25 per sq ft.

Pretty happy to find an environmentally friendly product is cheaper. ;)

[HORSELOGGER]

Al... 50 cents per sq ft per inch of thickness. I went with 4 inches of thickness, so my cost was 2 bucks a foot. I framed the building, sheeted the outside walls with metal and that was the extent of my involvement. They had it done in 3 hours.....Hey ... wait a minute... thats about 700 beans an hour Maybe I need to find the FoamestryForum and change professions :D... Nah, them chemicals make a guy goofy after a while

[Ga_Boy]

Horselogger,

What did you do for the inside of the kiln?

Did you leave the foam exposed or cover the foam with some type of sheeting?

I like the idea of using foam, like you said no caulking to seal the air leaks.

[Den Socling]

I've seen DH kilns built with wood and sprayed with foam. That's it. It's done. After a couple years, they kinda look like a cavern.  ;D

[HORSELOGGER]

Yep, just installed my fans and loaded it up. We have bumped it a bit, as would be expected, but no ill effects. I found it really easy to maintain my desired temp this winter, but it is really easy to overheat in summer.

[UNCLEBUCK]

I have seen this spray on foam on the web and it can be shipped in kits that look like 5 gallon gas cans along with nozzles and instructions ,its some kind of pre-charged can ready to go for the do -it yourselfer ! I found it on askjeeves somewhere . Looked like a popular place .

[Don_Lewis]

The do-it-yourself kits usually are expensive and/or make too light foam for a kiln. You need at least 2.2 pcf density for the long haul in a kiln chamber. Also, be sure that it is installed in multiple layers with no pass being over 1.5" thick. If you do these steps you will have something that will last many years. I have seen kilns 20 years old that were done right and standing up very well and I have seen kilns where the foamer decided he knew better and in 3-4 months, there were serious problems. Most of the guys that blow this stuff seem to have inhaled a bit too much of it and will argue the points. But this recommendation came from the two leading foam manufacturers and has been proven over the last 20 years many, many times.