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I have been working on this solar kiln off and on all summer. So today I moved it outside the shop and wired up the fans and thermostat. It is pretty much done now and ready to dry lumber. The inspiration came from Virginia Tech's design which I modified and adapted to my own needs and taste. The walls and floor are totally insulated with fiberglass insulation. The doors have an inch and a half of styrofoam sandwiched between the the siding and the inside sheeting. There is a layer of plastic covering the fiberglass insulation before the inside sheeting was installed. The sheeting is 7/16 osb painted with aluminum fiber roof coat paint and then painted flat exterior black. The roof is poly carbonate sheeting. I'm not sure if they will hold up or not but I am using window box fans for circulation. The 4 fans will pull in cool air from the top vents and will blow across the top of the lumber stack, down the front of the pile, thru the lumber stack and then exit out the bottom row of vents. There will be a tarp baffle installed just under the fans that go down to the lumber stack so that the air can't go straight down and out the bottom vents without going thru the lumber to be dried. Winter is not the best time to use a solar kiln but I'll try and see what it can do. At least I will be ready to go in the spring! This is my first experience using a solar kiln but I am pretty optimistic about it. I ran into a guy the other day that has a solar kiln and he had it facing west instead of south (because that is where it fit in front of his shop) and he just had a little solar fan circulating air inside with no circulation to bring in cool air and exhaust hot moist air. He thought it worked pretty good and was drying about 3 batches of wood during the summer. So I figured that if his works that good, mine should work a lot better. Thanks for looking!

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Looks really good and like it would hold more lumber then I could use in a couple years. I could use one like it that could dry a 100-200bf at a time. Do you have a mill to go with it or just buy a lot of wet lumber?
 

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Your kiln looks great! We've admired Virginia Tech's design and often thought of making one but we already have a few thousand board feet of air-dried lumber stored and are getting older-running out of time to use it all!

We'd love to hear how it works out for you.

L/W
 

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Looks great very nice work.
 

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Brilliant idea - not the usual cutting board or table for sure. Let us know how well it works from time to time.
 

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Interesting and great job. should serve you well.
 

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That looks great!!! As a matter of fact, it looks just like the one I WANT to build!

Could you please provide a link to the plans??? PLEASE!!!

Did I mention that it looks GREAT!!!
 

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DIYaholic,

Just google "Virginia Tech solar kiln" and you'll find more than you have time to read. Here's the direct link to the plans.

pubs.ext.vt.edu/420/420-030/420-030_pdf.pdf

And the instructions.

http://pubs.ext.vt.edu/420/420-030/420-030.html

You'll find lots of webpages describing how to build and operate solar kilns. I'm in East Tennessee. The high temperature today will be in the high 60's and the humidity will be very low. Solar kilns work fine at these conditions. I've thought about building another one over my heat pump to supply warm air to help heat my house…

Hal
 

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It would be even better if the fans were solar powered!
 

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Thanks for providing the links!!!

I'm looking forward to seeing both your kiln, filled with future projects & those projects completed.
 

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Thanks for the post and the link. Looks like a great winter project.
 

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great idea. at least it's an controlled inviroment. looks like you can move it around with a forklift also.
 

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Winter will be a great time to test it! Insulated as you have described it should work well. Did you put a thermostat on your fans? I was planning to build one and had decided to use the thermostat from an attic fan to switch the fans on only when the interior temp exceeded (I forget what temp).
One thing I was puzzled by; why would you force the air down, against it's natural tendency to rise? I would have had the fans exhausting at the top and pulling cool air in the bottom.
You don't want to dry too fast as that will encourage checking and you need the moisture carried out.
 

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Great Job, You will love having a Kiln!
I built one on a trailer frame 2 years ago, works great. Just one note, those plastic fans won't survive the drying cycle. Temps in the top will reach 150 degrees plus. and the plastic will droop and melt. You will soon have to get some aluminum attic fans. they work great, just remove the roof flange and use the round blade guard to mount the fans. If you are so inclined they also have solar attic fans, but they are a little pricey for my taste (I am CHEAP!).

rs
YBNORMAL
 

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YBNORMAL is right, plastic fans will not hold up, I also use an aluminum attic fan in my solar kiln with a thermostat, which works real well. I have put over 2,000 bd ft of Cherry, White Ash, Basswood, Walnut, and Hard Maple through this kiln and it works great. Checking was virtually non-existent and have found no hard casening. This is a great way to dry wood, takes very little attention, and once you learn when and how much to adjust the vents, the drying goes smoothly. You're going to love using this thing. Have fun.
 

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I bet if the fans were solar powered you could get a government grant to pay for the thing.
They will pay for solar energy systems.
It's all just government money anyway, don't you know.
 

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Absolutely cool. I can't wait to finally build one! This is going straight to favorites.
 

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When I built mine I used the polycarbonate sheets and they have been working fine for years. Like Doug, I also use an attic fan. In the spring I use it to start seeds and the rest of the year I dry wood.
 

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Thanks for posting. Hopefully I'll get around to making one of these soon. I'll put yours in my favorites, for when that day finally comes!
 
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