Will this insulation work for solar kiln?

[Stevenjohn21]

I managed to snag a load of 8'x4' insulation from our jobsite that is used to insulate commercial warehouse roofing. It is made of fiberglass and Foam and is 1.5" thick. 
Would this be ok to use on the walls and the floor of a solar kiln? 

[Southside]

You need to find out the temperature rating for the material.  Not all foam is the same. 

[Don P]

But roof insulation in Hotlanta is probably good for what a kiln can put out. It looks to be polyiso, i think you're fine.

I paid $49/sheet for 2" XPS foam earlier this week.

[doc henderson]

does it have ID printed on it.  I agree it should work.  translation, it was free and I would use it!  The silver side should reflect heat so the peak of 200° inside the kiln (air) will never see the foam of the insulation.  how old is it.  It might be different than what is used today, looks to be in good shape.  look up the rating for that brand and type to be sure.

[Stevenjohn21]

does it have ID printed on it.  I agree it should work.  translation, it was free and I would use it!  The silver side should reflect heat so the peak of 200° inside the kiln (air) will never see the foam of the insulation.  how old is it.  It might be different than what is used today, looks to be in good shape.  look up the rating for that brand and type to be sure.

The only thing printed on it is:
LGA 021122 "this side downward" 
The insulation is brand new, it's what was leftover from a job and the roofers were throwing it in the dumpster. 

[Sod saw]

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When you install foam board, you should use double layer (triple layer in the floor) thick with the joints between the second layer board pieces not on top of the joints from the first layer.  They should be staggered just like you see in a concrete block wall.  Furthermore each joint between foam boards as well as corners should be spray foam filled to cut down on heat loss (air flow).

Remember that the difference between the inside and outside of the kiln can be greater than the difference between the inside and outside of your house.

Its always a good idea to cover foam insulation to protect it from abrasion.

Doc is correct in that, a solar kiln could approach  200 degrees F, or more.

Good luck with your kiln build.


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[taylorsmissbeehaven]

That might be a good candidate for the score of the day thread! I hope it works for your kiln. As DonP said that stuff is close $50 each at the box stores. I just insulated under a slab and was shocked by the price.