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Pre-build solar kiln questions(Photos of kiln building progress)

Started by caveman, December 25, 2013, 09:29:11 PM

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caveman

We have a couple of dehumidifiers that we will use to remove the moisture.  There is still work to be done before we can start attempting to kiln dry lumber successfully.  The biggest obstacle is running electricity to the kiln from the shop ($$$). Also, we need to mix up some stain (boiled linseed oil, diesel and roofing tar) for the outside and make the bottom look more presentable from the neighbor's perspective-she is a great neighbor and I hope to keep her happy.

As of now, we intend to power two kiln fans, two room dehumidifiers, a light or two, and maybe a few outlets (nice to be able to plug in power tools).  Is there any other electrical appliance that we are missing?
Thank you,
Kyle

Caveman

caveman

WoodDoc, the dehumidifiers will drain outside through tubes through the floor.  Thank you for your expertise and helping all of us aspiring to produce quality lumber.

After moving the kiln yesterday, we were a little apprehensive that the roof may leak due to the flexing during the move.  It rained about 3" in two hours this morning and thankfully the inside of the kiln is bone dry, everything else is flooded.  Blind hogs...
Caveman

GeneWengert-WoodDoc

It is obvious from the pictures that you have a well designed kiln.  "No leaks" is indeed awesome.  Maybe you should use pine tar on the bottom and add a rudder so you can use the kiln as an ark, if it rains really heavy again.

Venting, instead of DH, can be more efficient, especially with wood that dries easily, like pine.

For your reference, 1000 bf of lumber requires removal of about 28 to 30 pints of water to lower the moisture by 1% MC.  So, with the amount of lumber in the kiln and the rated capacity of the DH units, you can calculate the maximum drying rate.  This would apply to wet lumber.  The units will not dry at their rated capacity when the wood is under 30% MC...we are waiting for the moisture to move from the interior of the wood to the surface, which depends on temperature and humidity and not the ability of the DH unit.

The clear cover will actually lose a lot of heat when dark.  So to prolong the usefulness of the DH units at night, cover the collector with an insulating blanket and the heat will stay in the kiln.  Of course, with 24 hour drying that will result, you will not relieve the stresses (also called casehardening).  This relief is accomplished in a kiln without a DH because at night the humidity in the kiln reaches 100% RH as the kiln cools.  Plus in a vent solar kiln, the fans are turned off at night.r

Also, be aware that the household DH units usually will not work above 113 F...they may have an automatic shut off.  Above 113 F, the lubrication fails, so the compressors will wear, plus the compression cycle may fail too and blow a gasket.  So, you would not use them when the sun is shinning, so you need vents to exhaust moisture in the daytime.  Technically, the vents are not opened very wide...just enough to keep the RH from getting too high.  We want to avoid exhausting too much heat.  Most kiln operators adjust the vent opening once a week.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

caveman

It has been quite some time since we updated this kiln build.  It still has not dried any wood but we ran wire to it last week to power the fans, light and dehumidifiers.  We still need to finish the wiring.  Jmoore and I mixed up a variation of the Uncle Larry's stain concoction and sprayed and brushed it on using a TSC pump up sprayer and a brush.  The pine really soaked up the mix.  The cypress we recently sawed will be the first wood to be dried in the kiln.  It will air dry for a month or so and then we will finish it off in the kiln.

 
Caveman

caveman

Today, Jmoore and I finally got electricity to the kiln.  We ran a separate circuit for the dehumidifiers.  The fans are on the same circuit as the mill shed.  We wired the timers, lights and an outlet or two.  He and I work for the local school board and have had the past two weeks off (except for emergencies like busted water pipes and greenhouse irrigation woes-life of an ag teacher).  We have run several hundred feet of electrical wire, PVC pipe, mixed and applied stain, wired the mill shed and kiln and found time to mill some really nice bald cypress.  The hot air was really moving when we turned on the fans today.  I am anxious to see how this contraption works.  I guess the next purchases will need to be moisture meters and thermometers for the kiln.

Caveman

caveman

Update:  We finally stacked two small loads in the kiln yesterday.  One stack of "not very good" cedar slabs and a stack of monkey puzzle slabs were put into the kiln yesterday.  This was the first time we removed the large panel that we made the skid steer attachment for.  It did not do too bad but it is much easier to remove and install with two people. Basically, we needed room to air dry some nice cedar we sawed yesterday and want to get an idea of how long it will take to dry 2" slabs to below 15%MC.

 
I think once we get the ground on the same plane as the kiln and remove the irregularities installing the panel will not take but a few minutes.  We have a door on each end that the panel fits between.
Caveman
Caveman

YellowHammer

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Planman1954

Yes...please keep us updated! You are the reason I took the time to document the build process. It makes me happy that someone took the initiative to go for it! Take pictures and post your drying times and progress. Thanks.
Norwood Lumbermate 2000 / Solar Dry Kiln /1943 Ford 9n tractor

caveman

A few minutes ago I went out to the kiln to check on the 3/4"x3 1/2" 14' boards we stuck in there 12 days ago.  We still have not installed vents or turned on the DH.  The first week we just propped the doors open with stickers (the kiln stayed quite a bit warmer than the outside even after dark).  The past six days we left one door propped open 3/4".  The wood seems dry enough to use to mount over shingles and attach metal to.  We still have not purchased a moisture meter. 

The Monkey Puzzle and cedar slabs that were in the kiln were considerably drier/lighter after a little time in there with the fans running during the daytime and the doors propped open slightly.  They are now flat stacked and in hiding.
After listening to Dr. Gene, WDH, and Yellow Hammer this weekend discuss drying wood at The Project, I think this kiln has a chance to produce quality lumber.

The cypress that was intended to be the first load in the kiln has been sticker stacked and drying in the wood owner's shed since early January.  He has decided to use it on the outside portion of his house so it will not be placed in the kiln.  We still have a good whack of his cypress logs that we will saw eventually.  After hearing Jake mention bad behavior by partially dry cypress logs I am beginning to get a little anxious about them.
Caveman
Caveman

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