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kiln questions

Started by sully, July 29, 2012, 02:11:16 PM

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sully

I am building a solar kiln.  So far it will be 12x5.5'.  On the one side it will be 9'tall but where i am able to put it It will slant to the loading side.  I was going to keep it at 6' so i would not keep knocking my head.   I am in nebraska so it would be only about 35 degree tilt instead of the 40plus that it should be.  I am hoping that this should still work.  I do have electricity right there so If i need to i can add a dehumidifier.  what do you guys think?   thanks so much    sully

Dan_Shade

I would make the roof angle your latitude  plus ten degrees and point it south.  this is known to work
Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

Compensation

Latitude plus ten for sure. My advice, use hinges on your ridge beam and side supports so you could lift the polycarb up and out of the way. Make the lower section fold down and use as a ramp mine is 8x12 and about 9 or 10 foot tall. I have less then 700 since i got all but my floor plywood for free.
D4D caterpillar, lt10 Woodmizer, 8x12 solar kiln, enough Stihl's to make my garages smell like their factory :) Ohh and built Ford tough baby!

Tree Feller

The roof angle needs to be your latitude +/- 5 degrees for optimum solar gain. For a "fill-it-and-forget-it" operation, you want 1.0 square feet of solar panel for every 10 bf of lumber capacity, ie, 500 bf of lumber = 50 sq ft of solar panel. Those dimensions are based on drying White Oak which is one of the more difficult woods to dry properly since it has such a slow drying rate...about 2% per day MC loss. If you have too much solar panel, the wood can dry too quickly in optimum conditions. Too little and it will never reach the 7%-8% MC needed for indoor use.

Note that the addition of a dehumidifier means it is no longer a solar kiln, but a hybrid, and drying rate will have to be monitored and controlled carefully to avoid defect from too-rapid drying. The safe drying rate for lumber is not an average rate over a week or several days. Exceeding the safe rate for even a single day can ruin the product.

I assume you have studied the plans for the VT kiln as designed by Dr. Wengert. If not, I'd suggest you do and not stray far from them regarding capacity, solar gain, air flow, etc. It's a proven design based on sound engineering.
Cody

Logmaster LM-1 Sawmill
Kioti CK 30 w/ FEL
Stihl MS-290 Chainsaw
48" Logrite Cant Hook
Well equipped, serious, woodworking shop

jimF

Sully,
As mentioned, the VT design is good for oak.  What species are you intending to dry the most?  If it is a species prone to stain, more solar collector area would be beneficial as well as the optimum collector slope.  The design was originally based on the available material more than optimum drying for any species.  So deviation would not be devastating.  Using a dehumidifier would require more attention to details but again if the species intended to be dried is prone to stain, this would be a benefit.
Know what you intend to do and what equipment you have available then plan accordingly and go for it.

GeneWengert-WoodDoc

ThE VT design was for 4/4 red oak.  The vents are not opened very wide, especially initially.

For slower drying (such as thicker), then cover part of the collector.  Avoid opening the vents very much initially.

For faster drying, load less wood in the dryer, open the vents wider open or consider air or shed or fan shed drying initially.

Vents are always kept nearly closed at the end to get high temperatures and low final MCs.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

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