Forced Air Circulation in a Solar Kiln

An example of a fan-and-plastic-sheeting setup that forces air through the lumber stack. May 14, 2006

I have heard people talking about a drop curtain mounted on the bottom of the fans that goes to the floor, but I have not seen any design specify to use a drop curtain. Should I use one or not?

Forum Responses
(Sawing and Drying Forum)
From contributor B:
You need some way to direct the hot, dry air through the wood stack. When I close the kiln door, I attach the near edge of the plastic to the side of the door and all air blown from the collector has to go through the stack.

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From the original questioner:
Thanks for the picture. How do you attach the plastic to the wood stack, also the door, and the far wall? It looks like attaching the plastic to the wood stack, it would be hard to keep the air blocked. I like your idea. I just don't understand how you get the plastic to work.

From contributor B:
The inside of my kiln is plywood, so I just stapled the 6 mil plastic to a 1x2 and rolled the plastic around it about 1 1/2 turns and screwed it to the ceiling next to the fans and straight above the leading edge of the wood stack. I wrap the bottom of the plastic around a 2x4 and roll it up until it is even with the top of the stack and I just lay it on the stack. I have about 18" on each end and I slit the plastic, take a sticker ( I use 1"x4' strips of 3/4" plywood) and roll a bit of plastic under it and screw it to the wall and pull the other side of the plastic to the stack and staple it to the stickers in a few places - enough to get a decent seal. Above the stack I use duct tape to close any cut plastic together. Just use common sense and you can figure out how to seal up so the air is directed through the stack. It is not air tight, but does not need to be. When I empty the kiln, I bunch the plastic up a bit and get a sticker under it and screw it to the ceiling. About 3 stickers hold up the 19' of plastic.

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