Final Piece of the Puzzle, Solar Kiln Build !

[caveman]

Your kiln looks really good.  We took another small bite of the elephant this morning.  We finally got the inside of ours sided.  We are still looking for garage sale timers and fans.  I was real impressed with you plenum and fan installation.
Caveman

[WDH]

Andy,

Very neat and professionally done.

[Bill Gaiche]

Looks good. I used that same timer on my fans until I changed to solar. It worked real good. I don t think Nancy will like the ditch job. bg

[Andy White]

Bill,
She really don't mind too much, because most of the trench will be going thru her lily beds beside the shop. Don't want me near them with a shovel, or a lawn mower!!!  8) 8)    Andy

[Darrel]

Thanks for all this fine documentation.  I've read quite about how to build a solar kiln, and seeing these pictures brings it all together.  Now I'm thinking that I can do this, where as before I wasn't too sure.  Once again, thanks.

[hookdrvr]

Andy,

Great thread and thanks for sharing the pictures of the build. I'm curious though, I noticed you closed the kiln in like an oven, it makes sense that it will heat up really nice. I've also seen pictures of some kilns that only have a wood or plastic seperator to keep the fans seperate and the wood is in the direct sunlight. Any thoughts on advantages or disadvantages on the two setups? I'm hoping to build a kiln this year and really like your setup, but wanted to get yours or anyone elses thoughts.

Thanks

[Andy White]

hookdrvr,
The collector panels separate the wood from the sun. They are the black panels mounted under the clear panels of the roof. The baffle will hang from the collector panel/fan plenum to top of lumber stack. A dehumidifier will be set in the chamber to run at night to lower moisture before fans start in daylight to circulate heat. Repeat cycle until dry. This is the way I understand it from several members that have been running this type kiln for a while.
If I am wrong or missed any details, someone will get on here to clarify for us.     Andy

[Andy White]

Got the new data logger this week, and couldn't wait to try it out! Downloaded program, set up configuration of logger to read every minute, temp and humidity. Logged in the house awhile, then outside, blew into it to see if humidity alarm worked. set the high range at 75% and it worked! This unit will make fan and DH timing so much easier. If you think you might use one of these, PM me and I will share the contact info. I love mine, and can't wait to load the kiln and put it to work! 8) 8)     Andy

[Andy White]

Well, I finally finished the last bite 0f my elephant, now for dessert. Got the door built and hung. Works like a vault door, heavy and tight fitting. Decided to build a latch for it, cause I'm tired of going to town for bits and pieces. I used the last of the White Oak scraps from Austin's bench build, and it works better than a store bought latch.


  

  

 
I used the last 17" pine boards for the door panels on outside.


 
Got the Ditch Witch started early today, and she got a trench dug for the conduit to the shop.


 
I hoo0ked up and run final test on complete electrical system, and all is good. Done a little finish work on the dirt from trench, and started logger to get some baseline readings with door closed and fans running.


  

 
Tomorrow will tell how well this thing s going to work. Will post results of  today's logging.  8) 8)  Andy

[WDH]

You have built a fine kiln, and you should have a big smile on your face.  I am very interested in the data log readings.

[Andy White]

WDH
Just went out to retrieve the logger that has been logging since 11.40 AM. Door closed and fans running, sunny skies and outside temp 74°F. Can't believe the temps. this thing runs! Now all I have to do is learn how to convert a CSV file to JPEG for downloading to my album. Maybe I can put a program together to help program fan and DH timers, These may need to be adjusted as seasons change???      Working the brain now!     Andy


 

[pineywoods]

Andy, that is one fine piece of workmanship. The temp/humidity numbers pretty closely match my experience. Notice the sharp rise in humidity when the sun goes down. That's the point where you need the dh to come on, otherwise, you may get condensation on the glazing and rain inside. It will be interesting to see how much the numbers change when you load the kiln with a stack of wet lumber.
Nice job...

[WDH]

I wonder that those temps humidity are too extreme for green oak.  With pine, that would surely be drying in style.

[Andy White]

Danny,
These readings are in an empty kiln. Maybe they won't be as high with green oak or pine If not, I may have to add a vent?     ??? ??? ???     Andy

[WDH]

You are right.  Evaporating water from the wood will lower the temp for sure.  You might need a vent to control the temperature if it starts to get too high.  That is how I do it with my Nyle kiln since I have to keep the temp below about 125 degrees.  Above 130 degrees, the compressor has a high temp shut-off and will not run.  There is an intake vent low on one side and an exhaust vent high on the other end of the opposite side.  Cracking these vents controls the temperature.  However, my chamber does not go through the daily temperature and humidity cycles that a solar kiln does. 

With fast, easy drying species like pine and yellow poplar, you can really hammer it.  With oak, if you hammer it with high temp and low humidity, you can ruin it.  From what I have read, you have to size the oak load to match the solar collector surface area. 

[Andy White]

Kiln is now ready for a load of Red Oak. I will learn to run this thing with lumber that has been air dried since September. Then I will cut a load of Walnut to air dry a while the oak is getting done. The last phase of build is now finished. Painted all walls with rubberized paint. Not too dark.


  

 
Installed grooved bunks to floor joists for stacking lumber.


 
Cut 12' material for baffle attachments, and installed them. If the poly tarp don't hold up, I'll get some canvas.


  

  

 


 
I will roll tarp down to stack, and clamp to top board with spring clamps to keep fans from blowing tarp around.

Last thing Paint Floor with roof sealer. Hope it gets hard. I painted a strip around the floor before putting wall plates down, and it dried good.

 
This has been a very educational build for me and am looking forward to drying some wood. Thanks all for the comments and support.    Andy

[YellowHammer]

You have really done a first class job.  Almost a shame to work the new off it...almost...heck load er up and we can't wait to hear how the first load turns out
YH

[GeneWengert-WoodDoc]

Make sure that your temperature sensor does not "see" a hot surface or the sunlight.

[pineywoods]

Andy, here's another handy tip. Use 2 temperature sensors, one measuring the air temp going into the stack, another on the exit side. Air picking up moisture from the stack will be noticeably cooler. When the two temps get close to the same, no more drying is taking place. Cheap and dirty moisture meter that measures the entire stack..Uuhh, I forgot you have a humidity sensor, just put that on the output side of the stack...I'm looking forward to seeing at least 24 hours of loggged data with a stack of wet wood inside....

[Magicman]

The meat and potatoes have been fine.  Now I am ready to see some Ice Cream.   

[Darrel]

I am very fascinated by this whole process and it is my plan to build a solar kiln in the not to far off  future.  Seeing what you have done will be most helpful when it is my turn to build.  I just have one question.  I understand how rhe air is heated and moves through the lumber stack by use of the fans.  But after the heated air travels through the stack of lumber, where does it go?  I feel like I must have missed something even though I've read this entire thread several times.  Thanks for clearing this up for me.

Darrel

[Planman1954]

Galv. metal painted black is secured to the BOTTOM of the rafters, and with the plastic clear panels on the top of the rafters, creates a chute (or plenum). There is about a 6" gap left between the front and back walls and the metal. So the metal is cut about 12" shorter than the length of the bottom of the rafters, and installed roughly in the center. A drape is attached to the bottom of the metal (forward of the lower 6" gap) so that air is blown by the fans into the stack from the top plenum (space between the rafters and the little mini attic at the top), goes through the lumber, and then forced by the drape back up into the bottom of the rafter plenum through the back wall 6" gap. Imagine a big circle going around and around the walls, floor, and ceiling. That is how the air (heated in the chute) circulates.

[Andy White]

Darrel,
Planman has summed up the scenario pretty well. I have been away a while this last few days, and left the kiln ideling without fans or DH running. It gets about 120° during the day, and down to about 80° at night. I think that is due to the insulation  in the walls. The Oak has not gained or lost moisture in over a week. The Wagoner says it is at 11%. I guess this would be a good storage shed when it is not running.   Andy

[Gadrock]

So now it has been quite a while for the trial period to have run its course. How about some update photos and information.

Possible for you to include some newly discovered "do's and don'ts"? Many of us are planning on making the same adventure and are seeking shortcuts to success.

Carry on

[Darrel]

I concur.