I found some used greenhouse panels for sale. Lexan 2 layers with spacers between to make 5/8" thick. Question would this work good for the roof? Not sure how much yellowing they have, seller says pretty clear. Would this dead air space help or hurt? I live in NW Pa so not real hot here. Talking 8' 9" x 4' for $25.00 seems fair. Thanks Tom
I have seen this on some kilns and it seems to work well. The air space is indeed an advantage. As you imply, it may age with time and not be so clear.
Sounds like a good deal and they should work well, depending on the yellowing. At that price you won't have much money in it. One thing to look for is how he had it attached and where the holes are. You may need to frame to match the existing holes. To me it sounds like it could be a real good way to go.
Should work fine as long as they aren't too yellowed. As long as they are usable you can't beat that price. For a greenhouse application they are used to help keep heat in so should do the same thing in your kiln.
Thanks for the input I hope to take a look in a day or two. The seller also has another material but says it has yellowed more.
I'd use it.
Well I bought some, so now I am committed to build. Seller said it is lexan, a heavy 1/16" top and bottom with ribs in between 1 1/8" apart. 5/8" thick over all and clear enough to read a paper through it. Hope to start this winter. Thanks
That's a good deal. That stuff is really expensive new. I'd be tempted to by some extra pieces if you had a good place to store it. Good luck with your build.
Even if it's yellowed, it still may be usable. Transparency to visible light is un-important, it needs to be transparent to infared radiation. Infared is what makes the heat..
Pinewoods is correct...about half the solar energy input is visible and half is near infrared. The ideal cover is transparent to solar and near infrared, but reflects far infrared back into the kiln. There is no question that two layers are better with a dead air space between them. Most glass that is not green colored when looking at the edge is fantastic for a cover, but is certainly at risk for damage from hail or rocks.
Near infrared comes from hot sources that are really hot like the sun. Far infrared comes from items in the kiln that are only 0 to 200 degrees in temperature, like a black painted wall, pile cover, etc.