Solar Kiln Basics

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George Vondriska features a home made Solar kiln. A WoodWorkers Guild of America (WWGOA) original video.
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[@michaelborn3318]

Having designed several kilns myself, including my first solar kiln in 1981, I would have a few suggestions. First, a cement floor would act as a thermal storage unit and level out the nighttime temperatures and reduce the condensation that occurs at night. 2 more fans would increase your airspeed and reduce the time needed to dry. 2 x 6 construction allows for more spray foam insulation. 2 vents on the ends would allow for more efficient water removal by venting moisture as it's being removed and allow for better maximum heat control.

[@Wwgoa]

Thank you for your suggestions!

[@unorubbertoe]

When he said "Radio Shack" I had a nostalgic wave of memories

[@berealrelentless6237]

soo funny was gonna comment on the same thing!!! BRAVO!

[@KeleFPV]

When he said Radio Shack, I also had a nostalgic wave of memories. I went to comment and realized you beat me to it.

[@nateb4543]

That line made me realize the video is 12 years old

[@fishhuntadventure]

@@nateb4543 That line made me wonder for a minute if was the onset of Alzheimer’s or something. The anachronism took a second to register.

[@maxdecphoenix]

This thing really is bad ass. My only critique is that this is actually a solar dehydrator than a 'kiln'. Dude could use this thing for all sorts of stuff, food dehydration, hot water preheater, I'd bet he could even use it as a plant nursery in winter to get a jump on spring. 135 really is pretty high for wisconsin. There's a video here of a group prototyping a hotwater preheater in that got in that range and I think they were in Tenn.

[@blackmonarch1]

I'm going to build one and put it to the test, cheers for this excellent video.

[@7amido_613]

Excellent video demonstration skills and humanitarian behaviors!

[@aeward2000]

Awesome video!. Very educational. Can someone please share with me where I can find the blueprints for this solar kiln/dehidrator. I need to build one in January. Thank you very much in advance.

[@noxagol]

@ben92282 Convection. Instead of fans, you could have a radiator type deal on the back that creates a cold zone. The temperature difference will create pressure difference which will create a natural airflow. However, this will also create condensation that you will have to deal with. The air would heat up in the kiln and travel up. Vents in the top would have this flow back into the radiator where it would be cooled and it would drop down. This would push the air out vents in the bottom.

[@aaronthomas8834]

The only way it could get better is if the fan were solar powered as well...

[@BillyAteMySoul]

This is pretty awesome. I'd probably set a small solar panel up there to power a few computer fans, and have a little controller that turns them on when the temperature gets to a certain point. Possibly also a 5 gallon bucket of salt in the corner- help pull the extra moisture out of the air at night, and avoid condensation inside the kiln. This is bad ass. I might well build one of these sooner rather than later!

[@13highvoltage]

In the video you mentioned the you set the timer for the fan to turn on mid morning. If I was to use a solar attic fan I would need to know the temp for it to turn on. Wondering if you knew what temp should be for the fan turned on. I live in North Florida so in the summer the temp. would take a little longer to drop at night would that be a problem; due to our high humidity in the summer.

[@davidsoudek]

One great thing about Oklahoma. Air doesn't get that dry for long enough to affect wood to that degree. Always heard to shoot for 6-8% moisture. You can get away with wood in the teens if you live in area with a higher relative humidity year round.

[@mettevuns2834]

In Denmark, where I live, the weather is quite moist and the temperature from 23-68, lowest in winter. Will this kiln dry wood throughout the year under these circumstances?

[@ben92282]

is the fan plugged in to the grid? is there any way to sufficiently circulate air without electricity?

[@samuils]

What about during winter or very cold weather? What about the speed of dryi9ng as compared to other low tech kilns?

[@IntoTheDirtshop]

how long did it take to get to about 10%?

[@Clintboyd]

Lol RadioShack! Awesome kiln.

[@SCscoutguy]

I really miss RadioShack. There Christmas catalogs were awesome.

[@milk5288d]

Does anyone know how hot is too hot inside this kiln? and How fast is too fast to dry out some red oak or black walnut? My slabs of wood are cut to 1" My kiln is 4'x8' and I live on the central coast of California.

[@Daveyhunter6]

do you have an issue with sticker stain?

[@patthomas3027]

what about in the high humidity like south Alabama?

[@skd5432]

Can u make a video of how u make this kiln!?

[@papablev]

I don't remember where I had seen it, but one of the sights I visited said that 7% moisture was acceptable for furniture and cabinet building. Just FYI.

[@zhache]

How do you know how long is the process and when is done? Its easy for me to build it and put lumber in but am week in theory like when is the wood done dry.

[@CroakerOutdoors]

$20 wood moisture meter. Two prongs stick in and take a reading.

[@777strongcoffee]

snap disk controller to turn the fan on/off automatically (from grainger)...

[@777strongcoffee]

snap disk controller to turn the fan on/off automatically

[@guybartlett9587]

Subbed

[@Wwgoa]

@milk5288d If you search the web for solar kiln information you’ll find many sources that can help you determine drying schedules and heat requirements. Check out the USDA Forest Service, which has publications available.

[@markbowron9273]

WoodWorkers Guild Of America

[@Thunder_Ridge_Ranch_KY]

How do I find the appropriate roof angle for where I live?

[@jlgoins64]

never thought about the salt, but it seems to be a good idea.

[@contrafax]

R.I.P. Radio Shack.

[@localcrew]

Those tall blocks on the bottom are unnecessary. You're cheating yourself out of a few more layers of lumber. I just use sticks for my bottom layer. All you need is slow air movement. A little is plenty. The heat of kiln-drying kills borer beetle larvae. This is a *huge* advantage over air-dried lumber. This is a nice kiln for the practicing woodworker. If you need more capacity you can always build another just like it! Thanks for posting this video.

[@fredcaslavka2446]

I have access to large insulated glass sashes and panes. Can I use them instead of polycarbonate? Better or worse than polycarbonate?

[@lecheelemental4739]

Better

[@druelymcburgerbun7541]

What is the difference in using green roofing vs clear roofing

[@Wwgoa]

Hello. We haven’t done any research on this so unfortunately we don’t have any guidance for you on this. Thanks Paul-Woodworkers Guild of America.

[@Wwgoa]

A solar kiln works best, in Wisconsin anyway, in spring and fall. Summer can be a little too hot, and winter too cold. This changes with different parts of the country and with different solar kiln designs. Different kilns will dry wood at different rates. You’d need to pull specifications on each together to make a side by side comparison. The solar kiln can dry hardwoods in 3-5 weeks depending on the species and other conditions.

[@troywentzel5756]

Ñn

[@lucasedney4989]

What is the ideal temperature?

[@Wwgoa]

This is from Dr. Gene Wengert, wood expert, in an excerpt from this article: www.woodworkingnetwork.com/magazine/fdmc-magazine/learning-fundamentals-kiln-drying "Temperatures. Conventional dry kilns commonly use initial drying temperatures, when the lumber is more than 50 percent MC, from 100 to 130 degrees F. As the lumber dries, temperatures are gradually raised. When the lumber is under 15 percent MC, temperatures, depending on species, range from 150 to 200 degrees F; although 160 degrees F maximum is preferred in most cases." Dr. Wengert is a guru. Paul

[@shanek6582]

What would be the roof angle in Gatlinburg Tennessee?

[@lucasedney4989]

Take your latitude and add 15 degrees. So if your latitude is 40 degrees you'd add 15 to get 55 degrees and that would be your pitch. Hope this helps.

[@kevminion]

What I read says your angle matches your latitude. 45° latitude equals a 45° roof. www.wagnermeters.com/kiln-drying/solar-dried-lumber-moisture-concerns/

[@tjn2254]

I heard plus 10 degrees

[@survivalsearcher]

How could the controlability of the wood be the main factor when it is highly suggested to air dry the wood to 25% moisture content? You need to air dry it either way. I would argue the biggest factor would be that it kills bugs, so you don't infest your house. Also once you use a source of energy(solar) to push the water inside the cells out, the cell walls collapse and becomes much stabler and the wood cannot absorb and retain moisture in the same manner as it once could.

[@matteoviviano]

How many CFM fan do you need for a kiln this size?

[@Wwgoa]

Hello! Great question. I'll ask one of our experts and get back to you with their answer right here.

[@Wwgoa]

The fan in that kiln is rated for 1000 CFM.

[@matteoviviano]

@@Wwgoa thank you!

[@nuttiBONG]

Kilns doest not leave higher quality according to other sources

[@grahamclark9190]

Why are all internal faces of solar kilns painted black? Surely white is a reflector and will heat the inside space. As walls are usually 18mm (3/4") thick faced hen insulated this won't give a significant thermal mass.

[@Shamustodd1]

I realize this is 8 years old, but the first things I noticed were... 1- he never mentions what the magic temp is when the fan needs to be turned on and 2- why would he do it manually? A simple thermostat would the job for him.

[@MakingMovesMonty]

Radio shack!? I thought I was young till today I guess lol

[@johndorlean1133]

@4:09 "Buy them at RadioShack"... sigh.

[@johnnewman8673]

I know....I miss RadioShack too

[@diyjman5259]

So it holds one log how convenient what about the rest of the tree that won’t fit in there

[@elbob248]

Build a bigger kiln and STFU.

[@diyjman5259]

@@elbob248 wow you don’t have to be rude you pos

[@raymondswilson2012]

RadioShack he he