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General Forestry => Drying and Processing => Topic started by: farmfromkansas on September 02, 2019, 09:46:28 PM

Title: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 02, 2019, 09:46:28 PM
Finally got my wiring finished, solar panels are up and connected, and we had a sunny day today with the blower running from about 11 am till evening, although did not notice it turn off.  Before coming home, about 7:30 pm, checked for temperature in the reefer and it was 99.8 farenheit, and now I need to get a couple dehumidifiers to remove some moisture.  The plan is to use a timer and run the dehumidifiers at night and turn off before the fan comes on the next day.  Dr. Gene mentioned on another thread that it might be a good idea to paint the top black to add some heat.  I have 22' of solar panels for a 48' reefer box, so probably a little short, but no idea where to get more. The lumber is all 4/4 and has been air dried for more than a year.  Last spring I tested a couple pieces and my tester showed 11%, but it has been a wet humid summer in North central Kansas. Feel like I moved a couple states east. If I were techish would post pics.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 02, 2019, 10:49:57 PM
hey there.  are these electric or thermal panels?  i.e. does the sun make heat or electricity?  you could paint the whole container flat black, anywhere that is hit by the sun.  I have good luck in a container with a 70 pint dehumidifier, in a 20 foot container.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 03, 2019, 08:20:39 AM
They are hot air panels.  Have a furnace blower pushing air from the trailer through the panels and back into the trailer.  Did not check the temp of the air, but it is hot. Planning to get 2 dehumidifiers, and use hose to get rid of the water, do not want to have to dump them every day.  Be interesting to see how long it takes to dry lumber. Would have been great to have gotten it going a couple months ago, when the sun was not so high in the sky.
Title: Re: Finally got my hobby lumber dryer going
Post by: Crusarius on September 03, 2019, 10:19:53 AM
Run a hose and dump the water outside.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 04, 2019, 01:49:46 PM
Checked the temp in trailer this morning about 9, was 91.  About 10:30 came back and the fan had started blowing heat, and just before lunch was 98.  So the trailer does not lose much heat over night. 
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 04, 2019, 02:52:22 PM
sounds like a hybrid of solar and dehumidification.  any heat will help so no biggie.  if it was solar only then the board foot amount would be limited, or dry slow, but heat in the day and dehumidifier at night... I assume the solar panels are self contained.  how many square feet,  I think the ratio for solar is 1:10.  so 100 sq. feet of collector will do a thousand board feet of lumber, more if it is oak so it will go slower.  solar alone, you would just vent the moisture out.  a dehumidifier will add up front expense and also electric about like an ac unit instead of just a fan.  I have a remote "accurite" temp and humidity gage in mine.  it also records the high and low temp and humidity.  the base is in my shop 100 feet away.  about 14$.  sounds like you are having a fun interesting time!  @GeneWengert-WoodDoc (http://forestryforum.com/board/index.php?action=profile;u=20498) 
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 04, 2019, 09:33:58 PM
Have about 188 sq ft of solar panel, so know it is not as much as a solar kiln, but I don't need to dry a load a week, just enough to supply my woodworking addiction.  Thought I had plenty of storage in the shop, but ran out of dry wood last winter.  Thinking about building a solar kiln as well, now that I can buy cheap twin wall poly locally. Have had problems drying ash in the past, but was using no bug killer on the bark, and borers were ruining my boards while air drying.  If I had a solar kiln, would be tempted to put the boards directly in the kiln after sawing, with the idea of cooking the borers before they could totally ruin the boards.  
Title: Re: Finally got my hobby lumber dryer going
Post by: 69bronco on September 05, 2019, 08:05:24 AM
Just curious, where do you find cheap twin wall?
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 05, 2019, 08:35:13 AM
I have been told that Menards puts on sale a couple times a year.  I found a good deal on clearance at Lowes on corrugated single poly.  yes I am going to try a temp firewood solar dryer, but a shed to dry and store at the same time would be great, if you have materials and space. I use my container for storage and run a home dehumidifier in there.  but it has been off for months and I get little increase in MC since it is well sealed.  farm, cost of electricity is the only downside I can see with your system, to run the dehumidifier.  wet wood will really work it and chemical in the wood such as oak will decrease the expected life of the unit as well.  it would be interesting to see high and low temp. and throughout the day.  maybe you can just vent a little and run it like a solar kiln.  My wood was all air dried before going into the container.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 05, 2019, 08:37:52 AM
sounds like you have some holes for vents/solar ducts in your container.  If you can find and old wood fired outdoor air heat exchanger furnace, could plumb that in and use waste wood (if there is such a thing).
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 05, 2019, 09:30:15 PM
The reefer was removed from the trailer, so it left about a 40" x 7' hole in the front.  So I put a 2x4 around it, then studs, waferboard, then corrugated metal on the outside.  I put double r11 batts in the spaces between studs, as they were pretty thin and there was room for 2, then put waferboard on the inside.  Used a jig saw, cut the holes for the pipe to go through to duct the air out, and the heated air back in.  Used a furnace blower and thermostat to blow the air and turn the blower off and on, and have several plugs wired in on the side of the container, all in conduit, so I can plug in dehumidifiers and work lights.  Decided to get the wood as dry as possible before running the sterilization cycle.  After reading everything on the forum for some time.  And different plugs are on different circuits so should be able to hook up several lights, and monitor temperature, then turn some off as the temp approaches 150 degrees F.  As for the twinwall poly, look at the stock 4x8 panels at Menards.  They also have the joiner strips and fasteners in stock.
Title: Re: Finally got my hobby lumber dryer going
Post by: low_48 on September 05, 2019, 11:52:36 PM
It's going to take more than a few light bulbs to get a 48' reefer filled with lumber to 150 isn't it? I use a hot plate with a huge aluminum heat sink on top of the electric element in my woodturning kiln. It's a gutted upright home freezer. At about 3/4 full heat, it takes a couple of hours to get my little kiln up to 150.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 06, 2019, 07:24:23 AM
48, it is all an experiment, will see what it takes to get the heat up.  My first idea was to use a space heater mounted outside to blow heat into the trailer to raise the heat, but Yellow Hammer uses 500 watt work lights, so thought I would try his method.  
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 12, 2019, 02:18:57 PM
Question for the experts, put 2 dehumidifiers in the reefer box on Sunday, with hoses so they can drain out the corner holes, and this morning they were shut down.  Clicked both down to 35% and they took off.  Temp this morning in the reefer was 98.  Highest I have seen inside in the afternoon is 111 degrees, but at noon was already at 108.  Is my wood already getting dry?  After getting dry, plan to put the work lights to work and see how hot it will go.  Have different circuits, so can turn some off if it starts to get too hot.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 12, 2019, 10:08:13 PM
Checked the temperature in the reefer at 2:00 pm, and was at 115 degrees.  Hottest so far.  No chance to check it later in the afternoon.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 12, 2019, 10:18:24 PM
when the temp goes up, the relative humidity goes down.  at night the temp drops and humidity goes up and the DH can run and remove water.  remember RH is the amount of water the air could hold from 0 to 100% based on the temp.  are you monitoring humidity?  my shop was set at 62 degrees to run the ac, the 5 gallon bucket was overflowing and the humidity was 50%.  if it warms up to 70 it will be like 35% humidity.  I have been running it cool to remove some humidity after going a month without ac in my shop, and all my stickered wood re-tensioned  the metal strapping, so i know all the wood took on water.  is this wood air dried already, sounds like good temps from your solar.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 13, 2019, 06:49:46 AM
Yes, all air dried, and the dehumidifiers have the setting for humidity, yesterday morning they were set at 40% and had shut down.  So I clicked them down to 35% and they came on and later I checked the hoses, and a little water was dripping out. Seems a little heat and dehumidifying gets wood dry quicker than expected.  Will have to take a couple boards out and check the MC.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 13, 2019, 11:06:52 PM
I will bet the container air is dry, but maybe not the wood.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 14, 2019, 11:32:07 AM
Would think that the air temperature in the trailer getting up to 115 degrees, and dehumidifiers removing moisture at night would dry the lumber relatively quickly. Only way to tell is to cut a board or 2 in half and testing the moisture.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 14, 2019, 10:03:16 PM
how many board feet of lumber and how many gallons of water per day coming out of the dehumidifier.  my ac is putting out 5 gallons a day.  you only need about a 1 inch section through the board to weigh, then oven dry, re-weigh and calculate.  I am just saying the heat motivates the water, the surface is dried by the low humidity.  do you have a pinless meter.  I thought you started at 11% or was that someone else.  @GeneWengert-WoodDoc (http://forestryforum.com/board/index.php?action=profile;u=20498) can estimate gallons of water from starting at 11% in a particular wood and how much or how many pounds of water need to be removed.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 15, 2019, 09:26:53 AM
I put hoses on the dehumidifiers, so can not say how many gallons of water are being removed.  These cool nights have been helping, as the hoses are dripping in the morning when I check them.  Need to count layers to estimate board feet.  Good pile though.  Yesterday one of the air hoses came off between collectors and reefer, so did not get as much heat as usual. Took the leaf blower and blew between layers, and blew the dust out of the trailer, should have taken a board out to check.  My meter is a mini ligno. 
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 15, 2019, 10:08:33 AM
Went and checked the dryer just now, the temp inside was 94, one dehumidifier was doing nothing and the other was dripping a little, opened the door and went inside, both dehumidifiers don't seem to want to go below 35%, took out one board at the back, and one from the front, cut about 4" off the ends of both, one mullberry, the other walnut, and the mullberry tested 6 to 7%, the tester just changed without moving it, and the walnut tested 8 to 9%.  So getting there.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 15, 2019, 10:53:11 AM
home dehumidifiers are only designed to go to 35%.  under that in a home and things start cracking and lots of static, (not just from the wife).  low humidity in the air keeps the surface dry, but it is the high temps in the day that move the inside water.  you can do and oven dry test if you have a tiny scale like for 500 g ect.  I had one from our pinewood derby days.  I did a pre moisture on some firewood so I can see if a temp. solar kiln speeds things up.  you only need a 1" cross section from the boards you cut.  pre- weight, then dry until they stop loosing weight at a about 217°.  takes a day in a regular oven.  or faster in the microwave but more monitoring.  and or I use a wagner but its upper limit is 32%.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 15, 2019, 11:09:21 AM
 
(https://forestryforum.com/gallery/albums/userpics/51041/CF55DC31-A3D1-4737-A50F-22CAA872A7DC.jpeg?easyrotate_cache=1568559541)
 

side and center split from mulberry log


(https://forestryforum.com/gallery/albums/userpics/51041/54579D58-7893-42B8-860A-E1832D19C987.jpeg?easyrotate_cache=1568559671)
 


(https://forestryforum.com/gallery/albums/userpics/51041/7989284C-CCCF-4506-8455-224221212151.jpeg?easyrotate_cache=1568559541)
 

dry at 217° aprox.


(https://forestryforum.com/gallery/albums/userpics/51041/0BADA923-A3DC-4323-ADEF-EE691FA7EEF1.jpeg?easyrotate_cache=1568559732)
 
 

I did 3 from the center and three from the outside with sap wood, cut them to 1 inch think aprox.  got a weight and kept checking weight until no further losses in the oven.
subtracted the final from the original weight to get the weight of the water lost.  divided the water weight by the dry weight to get MC.  the inside was 34% the outer split was 41%.  by oven dry method.
 

Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 15, 2019, 11:27:17 AM
in my container I run the hose into a 5 gallon bucket (outside and lower than the connection to the dehumidifier) so can check and dump.  upwards of 5 gallons a day when wet.  yes most water at night. lower temp, higher humidity.  in a kiln with wet wood we may keep the humidity at 85% so it does not get as much gradient between the center and surface. (called wet bulb depression) bigger diff between dry bulb (temp) and wet bulb is lower relative humidity.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 15, 2019, 04:59:51 PM
what a gent.  @beenthere (http://forestryforum.com/board/index.php?action=profile;u=180) pointed out (by PM) that the water weight is divided by the dry weight.  that is sure correct.  I know that in theory the MC can be greater than 100% in cottonwood and such, and that would never be poss if the denominator was the largest weight.  so take the total minus the dry weight is the water weight that was baked off.  divide that number by the final dry weight for the MC.  as to not cause future confusion, I did modify my prev. post.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 16, 2019, 07:42:45 PM
This morning the temp in the dryer was 106.  Both dehumidifiers were running, could hear them humming from outside, and put my hand under both corners, and the ground was wet, and a few drips coming from hoses.  Don't catch the water, just run it out.  No scale other than the bathroom scale to weigh myself, but looks like the dryer is getting there.  Funny thing, this afternoon about 3:00 checked temp in the dryer, and was about 119, and checked about 5:30 before coming home, and it was back to 115.  So the sun works better earlier in the day, and although the fans keep running, the temp drops towards evening.  These dehumidifiers seem to work at higher temperature than some, but would be nice if they would go below 35%.
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 16, 2019, 10:45:31 PM
@farmfromkansas (http://forestryforum.com/board/index.php?action=profile;u=36643) I think early you want the heat, more than lower humidity.  at 35% it will eventually reach 7% just like in your house.  the heat speeds it up, @ 35% but 70° it will get to the same MC, but take longer just like putting it in your house.
Title: Re: Finally got my hobby lumber dryer going
Post by: farmfromkansas on September 18, 2019, 02:11:23 PM
This load will probably be done in a couple weeks, and I am wondering am I going to have to buy another container?  Have a couple more stacks that need drying, but after that, what do you do with this thing, just unhook the collectors, turn the electricity off and use it for wood storage?
Title: Re: Finally got my hobby lumber dryer going
Post by: doc henderson on September 19, 2019, 04:00:31 AM
yes but keep a dehumidifier going in there to keep it about 35% like your house.
Title: Re: Finally got my hobby lumbeoor dryer going
Post by: farmfromkansas on September 19, 2019, 09:30:59 AM
Thanks Doc.