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Author Topic: Sorta solar kiln  (Read 1897 times)

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Offline OlJarhead

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Sorta solar kiln
« on: September 23, 2019, 12:37:22 PM »
This is the stack before moving it into the 'kiln'


No heat source other than sun and what little the dehumidifier puts out.  One week in and some lowering of the MC.
Once uncovered I saw and was disappointed by a LOT of movement in the wood.  I can only assume it was part stress (there was a lot) and part how rapidly the wood started to dry in the dry desert climate here.

The 'kiln' is just 6mil plastic laid on the ground, two box frames on the end and some 1x6ish stringers to hold it together -- all plastic wrapped and sealed with a fan and Dehumidifier inside.


After one week some of the wood showed higher readings and I assume that's due to water movement.  it was all right around 12.5% at the start.


Some showed promise though!

The weather has not cooperated at all though as our usual sunny and hot late summer/early fall weather has not materialized and so far the hottest it's been is 75F....and mostly it's been cloudy and even raining!  WHAT!?!?!

I put a temp logger inside and every day I see water pooled around the hose (or a big wet spot anyway) so it's doing something and we'll just have to be patient to see how well this works.

My hope is that I can flatten out some of the badly warped slabs and at least use some of them and there is wood in there that didn't move much but WOW did I get a lot of movement in this English Walnut.  The logs were checked the moment they hit the ground though and were over 40% MC at the end grain so I'm guessing the stress and rapid drying had something to do with that (milled in Portland OR and bought to EA Washing to dry and use).

I've only dried a little lumber out here in the desert and it moved a ton then too so I thought that could happen again but this wood was on the more shaded side of the house with a roof over and lots of air movement around it but I'm guessing it was just too dry.
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Re: Sorta solar kiln
« Reply #1 on: September 23, 2019, 12:48:41 PM »
Oh and my hope is to get this all down to 7% or lower since it's a dry climate.  Not sure this will work but if in 3 weeks it isn't dry enough I'll move it into the garage in the same kind of set up but with insulation and a heat source and I'll pour the heat to it for the last week (or at least hope I can).
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Re: Sorta solar kiln
« Reply #2 on: September 23, 2019, 06:55:05 PM »
Thanks for posting.  I'd like to do this myself and have learned a lot from your pictures.  Here in the humid east it would be a little different.  Good luck adding value to your wood.  "Read and you will succeed!"
There might be a little dust on the butt log, but don't let if fool ya bout what's inside

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Re: Sorta solar kiln
« Reply #3 on: September 24, 2019, 12:04:09 AM »
Thanks.  Bighest issue so far is the darn rain!  Usually only get 8 inches a year or so but lately it's been pretty steady (for us) and I didnt out much roof support in
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Re: Sorta solar kiln
« Reply #4 on: September 24, 2019, 12:33:41 AM »
I wouldn't think wind helps you much either. That structure would make a nice sail. I was surprised how quickly visqueen breaks down in sunlight and heat. I experimented with a warm air solar collector in the 80s. My collector made it through the winter, but broke down quickly with the spring sun angle and heat.

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Re: Sorta solar kiln
« Reply #5 on: September 25, 2019, 09:32:27 AM »
I'm planning to try this soon myself (without fan and de-humidifier) when I get some boards air dried down to EMC. BUT, EMC around here is 14%.

Next ten days forecast here in South Georgia  95+ degrees and morning humidity of 85% or higher and no rain/ Gonna have some afternoons when the humidity drops into the 40s though.

Please keep us updated

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Re: Sorta solar kiln
« Reply #6 on: September 25, 2019, 06:32:11 PM »
Have to have those in the tent or it wouldn't work.  You have to have a way to get the moisture out.

After 1 1/2 weeks I am seeing very little moisture coming out of the hose.  Used to be several feet of wet pavement around the end, now just a small spot.  It's 75F today and might be like that the rest of the week so I'm hopeful I'm getting 100+ inside the tent/kiln because I'm guessing I need heat now to really get the last water out.

Plan is to open it again this weekend weather permitting.
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Re: Sorta solar kiln
« Reply #7 on: September 25, 2019, 06:44:38 PM »
thick slabs are going to "move"  all you can try is to weight them or strap them.. adjustable straps are best since after it shrinks/dries, the straps will be loose.  even though you are in the desert, if it is sealed up and with a dehumidifier, you should be able to replicate what ever environment you need.  although dependent on the sun for heat.  looks like you are having a good time.  the slabs that went through a branch point are going warp and twist no matter what.  use as rustic or mill it out.  best regards.
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Re: Sorta solar kiln
« Reply #8 on: September 25, 2019, 06:49:49 PM »
can you put a container under your dehumidifier hose to help quantify the water removed.  when the temp drops, the relative humidity goes up.  that is why it is called relative.  the dehumidifier will remove most water during the night, and may not be seen in the am as much.  I have been using the sensor push recommended by @YellowHammer .  it is cool to see the temp and humidity graph, they are just the inverse of each other.  I have mentioned on other threads that I have taking 5 gallons a day from my shop, after a month of no ac, and all the wood sucked up moisture.
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Re: Sorta solar kiln
« Reply #9 on: September 26, 2019, 04:23:40 PM »
Thanks Doc.

I raised the dehumidifier today to get it off the ground though I don't what what that will do.

Inside the kiln at 12:30 today it was 102 and rising and the dehumidifier was report exhaust MC of 30%.  I found that odd but it may not have the oomph I need either.

However 1" slabs are showing 5% now!  Just the 2" stuff is dow. To 10% with some still showing higher. (13% even).

It will get hot in there today so we shall see.
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Re: Sorta solar kiln
« Reply #10 on: September 26, 2019, 04:24:50 PM »

Another week to get down to 8% maybe?  But I still think below 7% is better for this climate.


Now I'm thinking I should remove the 1.25" stuff as it's obviously getting down to good range now.


Darn it!  I am surprised at how all over the place the readings are actually.



Interesting that it's showing 30% RH and so to is the dehumidifier.

2.25" slab showing 13.6% still....where is the scratching head emoticon?
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Re: Sorta solar kiln
« Reply #11 on: September 26, 2019, 05:35:31 PM »
Hmmmmm.....it's 31%RH here today and 30% in the kiln with an exhaust of 30% on the dehumidifier....might be the lowest it can go???
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Re: Sorta solar kiln
« Reply #12 on: September 26, 2019, 05:58:19 PM »
Incidentally, you might wonder why there is no weight on the wood slabs.  i was told it didn't move once below 16% and it all went in the kiln at about 12.5% so I figured I wouldn't need weight at this point.

Hope that isn't incorrect!?
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Re: Sorta solar kiln
« Reply #13 on: September 26, 2019, 06:17:50 PM »
 

Less than two hours after I entered the kiln and raised the dehumidifier 6" or so and closed it all back up I see this :D  So water's coming out again.  I have to assume the heat (it's been hotter today finally!  Hit 79F) is working in my favor now.
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Re: Sorta solar kiln
« Reply #14 on: September 26, 2019, 07:36:51 PM »
the higher temps move water cause it is closer to the boiling point.  a home dehumidifier shuts off under 35%.  it is most efficient at higher humidity and that occurs at about 4 or 5 am.  if you add a container, you can quantify the overnight water volume loss.  during the day the RH will be low as the temp rises.  the center of a 2.5 inch slab has to be higher than a 1 inch board that started at the same MC.  the probes measure the surface moisture unless they a insulated except for the tip.  the heat raises the amount of water the air can hold.  at night it will condense unless removed by your dehumidifier.  your meter should be set for average density based on species, but any density variation in a board can give a false reading.  such as sap wood vs a knot.
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Re: Sorta solar kiln
« Reply #15 on: September 26, 2019, 08:16:01 PM »
Ahhh good stuff.

I'll have to find a section of hose I can sacrifice and see what happens.  Was also thinking of sticking some finishing nails into a 2.25" piece and see how that reads from the middle.  I get much lower MC when checking the face (for obvious reasons mentioned above and something I do not do other than occasionally out of curiosity) but I check at the end grain and jam the meter in as far as it will go.  I get different readings that way (and higher ones).
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Re: Sorta solar kiln
« Reply #16 on: September 27, 2019, 02:16:53 PM »
Checking your moisture content on the end grain will give you lower results than other area of the boards. The real moisture content is significantly higher than you believe.
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Offline GeneWengert-WoodDoc

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Re: Sorta solar kiln
« Reply #17 on: September 27, 2019, 10:14:46 PM »
When checking the MC during drying, the best method is to use insulated needles that have the tips uninsulated.  These are driven at a depth of 1/4 of the lumber's thickness to get an average MC, or into the core (1/2 thickness) to get the wettest.

The next best way is to use two shiny nails spaced one or two inches apart and driven 1/4 or 1/2 thickness.  These will read the wettest along their length, which is ok if the surface has not gained moisture.  Run wires from these nail heads to a moisture meter.

You can measure humidity by using a thin piece of wood or a thick piece of paper and put that on the pins of a moisture meter.  Some companies sell wafers for this purpose...Lignomat is one.  The reading from the meter in this case is EMC of the air which can be converted to RH.
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Re: Sorta solar kiln
« Reply #18 on: September 28, 2019, 12:11:42 AM »
Checking your moisture content on the end grain will give you lower results than other area of the boards. The real moisture content is significantly higher than you believe.
Using the pin type meter (above) it gives me the higher reading then on the surface.   I'll be trying the nail method soon though.
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Re: Sorta solar kiln
« Reply #19 on: September 30, 2019, 03:47:43 PM »
Tested with some small finishing nails nailed deep in the wood about 15" back from the end and saw MC readings at 14.5% +/- (had a hard time holding the meter pins on the wood and no clips and wires yet).  So this shows an increase of about 2-3% over what I'm seeing on the end grain.  Don't know if that's to be expected or what.

Still see readings all over the place but clearly the 5/4 stuff is much lower showing as low as 6.5% on the ends.

My temp logger showed only 6 days in the last two weeks with temps above 100F in the 'kiln' and the highest temp so far was 109F which is about a 30F increase over ambient air temps.  We've had a very cool summer (coldest in 20 years) and cool fall so I'm not confident I'll get many days over 70F now.

I have to pull the wood inside in a week or two as we're having a shed delivered and I need the driveway space it's in now to back the shed into place.  However, I'm thinking that will be fine as I can restack it inside the garage and rebuild the 'kiln' there perhaps (if I decide to bother).

When I pulled the logger it showed temps 20F above current outside air temps and humidity of 37% which is 5% lower than what the weather sites tell me we are here today (42% RH and 48F with overcast conditions vs 67.3F and 37% inside the 'kiln).

Interestingly enough I did find RH to be higher then temps where lower and only on the 10th day did I see RH of above 50% (which is today/this morning).  So I can only guess when it's been above 30% the dehumidifier should be removing that moisture.  What I'm wondering is if it would be worth placing a small heater on high inside the 'kiln' to keep it a bit warmer in there day and night with the obvious exception that it will shut off if the sun ever decides to come out and heat things up again.
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Re: Sorta solar kiln
« Reply #20 on: September 30, 2019, 05:09:27 PM »
for heat, some just use halogen spot lights.  have you rigged a basin to catch and measure water output?  this can help you predict when the wood will be dry enough.  my ac in my shop puts out about 5 gallons a day.  aux. heat would speed up the process, but with plastic, no real way to hold the heat.  most water should be coming out overnight, with lower temps and higher RH.  if you can peak at the volume produced in am and pm, it will help confirm this.
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Re: Sorta solar kiln
« Reply #21 on: September 30, 2019, 05:28:31 PM »
Decided to do a little testing to understand better your points.


First with the end grain (great points made earlier, thank you!) and you can see 8.1%.  This is a chunk of walnut that did not make it into the kiln (and it's hard as bloody nails!  Bent my finishing nails a few times trying to drive them into it!)



Next up on the surface and 8.5% -- guess I hadn't jammed the pins in deep enough in the past.


Finally with small finishing nails driven into the wood (after bending a few -- sheesh!) and 9.2%

OK, so that's 5/4 that was just sitting in the garage for the last few months (hmmm5 months maybe?  I'll have to try to figure that out).
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Re: Sorta solar kiln
« Reply #22 on: September 30, 2019, 05:35:27 PM »
for heat, some just use halogen spot lights.  have you rigged a basin to catch and measure water output?  this can help you predict when the wood will be dry enough.  my ac in my shop puts out about 5 gallons a day.  aux. heat would speed up the process, but with plastic, no real way to hold the heat.  most water should be coming out overnight, with lower temps and higher RH.  if you can peak at the volume produced in am and pm, it will help confirm this.
Good point on the heat but I figured with 20F higher than outside air a small heater might increase it just that much more during the day and keep it above freezing at night.  Might be worth a go...I do have some insulation but would have to completely change everything.  In all honestly, I'd hoped for some normal weather with temps into the 90's....didn't happen.
Haven't gotten a hose in there yet that I can check how much I'm getting out of the wood daily.  Only option is to use the internal bucket but that poses it's own problems as I'd have to open the kiln daily which means cutting and retaping it daily....can be done, but not the best approach.
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Re: Sorta solar kiln
« Reply #23 on: September 30, 2019, 07:02:00 PM »
looks like fun.  eventually it will get there.  you could in theory calculate the amount of water removed in gallons needed to get close to the MC you want.  or see when the volume drops off.  the heat will just speed things up, but will be lost at night due to single layer plastic.
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Re: Sorta solar kiln
« Reply #24 on: September 30, 2019, 07:21:25 PM »
I used a TSC small forced air fan heater once, in my kiln.  It lasted awhile until the fan motor and shaft corroded and froze up and burned out the heater.  And I really mean burned it out.  Be careful.  
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Re: Sorta solar kiln
« Reply #25 on: September 30, 2019, 07:45:33 PM »
The real fun begins when my router slabbing jig and new 3.25hp Makita router shows up with 3" slabbing bit! :D  I'll have to make a table for it and get it set up for the first slab...and figure out how to secure the slab to the table....

But all that after the kiln/drying gets the wood to an decent level.
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Re: Sorta solar kiln
« Reply #26 on: October 06, 2019, 02:28:16 PM »
Did some changing in the 'kiln' today which I really ought to call drying tent ;)

First I moved the fan to the top of the stack in the hope that it will move air around the tent better and push warm air down etc.  Then I moved a small 1500 watt ceramic heater into the tent on the opposite end of the dehumidifier.  I had contemplated this as it's been down to freezing at night and only in the 60's during the day and I thought if I could raise temps to the 80's or better on sunny but cold days it might help.  My wife actually commented that the camper was 80F inside with this heater on fairly low and that it might boost the temp in the 'kiln'...so why not?

Then I drove some finishing nails into the wood and wrapped some wire on them (I have yet to pick up any clips) and stuck the wire out of the tent so I could check more often and without opening the tent.  Lastly I stuck the temp logger in and checked outside air temps (52F) before sealing the tent.  This way I can see what the low temp was when I started and track daily outside air temps for a week and see what happens with the heater in there.



Checked a pice on top of the pile and it was at 12.7% about 1" into a 2.25" piece.




Jammed the pins into a 1.25" piece and saw this



I should recheck this one as it seems a tad low.  It's on the bottom of the pile and a 2.25" piece with finishing nails driven about 1" into it.



Original test piece measuring 12.2% vs the original 12.7%.  Not sure why that is unless the length of the wire has something to do with it.

Still, I'm thinking at this MC I could if needed, flatten these out on my new router jig (I bought the The Stone Coat Countertop Slab Jig and a 3 1/4hp Makita router for that purpose :D )
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Re: Sorta solar kiln
« Reply #27 on: October 06, 2019, 09:26:25 PM »
Thanks for doing this thread, I'm a little behind you in the process, I've got a few slabs air drying for the time being. A solar kiln is on next summers to do list. A router sled will be a good December/January project when it's too cold to do much outside. I probably won't run a bit bigger than an inch and a half, or so at least til I  manage to free the magic  smoke in my old craftsman.
I hope you get healed up miss the milling thread. 

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Re: Sorta solar kiln
« Reply #28 on: October 06, 2019, 11:23:27 PM »
It is important to take the first reading that you see rather than waiting for a ten seconds or longer.  Do not apply the voltage for a long time.

From time to time, disconnect the wires from the nails and see of you get a reading...any reading means that the wires are leaking current.
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Re: Sorta solar kiln
« Reply #29 on: October 07, 2019, 12:07:54 AM »
Thanks guys.  I hope to get back to milling again myself!  I do have one job I've agreed to do and hope the weather allows it since I was snowed out last time.  A new shot in the elbow may help (had a special one a few days ago)...now we wait.

Thanks for the note on taking readings and the wire.  I notices the readings drop for a bit then stabilize.  Usually don't drop more than about 0.5 though.  So perhaps the 12.7% reading is the accurate one and the 12.2% was me fiddling too long trying to take a pic and holding the voltage on.

Going to drop to 25F in a couple nights so probably will have to kill the heat and dehumidifier since the water will free in the hose anyway....either that or disconnect the hose and see what happens.
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Re: Sorta solar kiln
« Reply #30 on: October 08, 2019, 03:03:47 PM »
Checked both today and saw 12.4% on the one that was 12.7% before and 10.1% on the one that read 9.7%

I'm guessing it doesn't mean much other than a couple days makes little difference. 

I do however, plan to move it all inside soon and will have to decide how to drive it down further then.  After all, it's getting VERY cold in the next couple days and no likelihood of any good warm weather left which this type of contraption really needs I think (at least to get it hot enough inside to evaporate the moisture out of the wood).

So, I'll move it inside and once I haven arrange the room will set it in a smaller box with the dehumidifier and fan and a heat source and see what happens then.

But I may flatten some of it out before trying to push it down further.
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Re: Sorta solar kiln
« Reply #31 on: October 08, 2019, 05:16:42 PM »
MAKING PROGRESS.   8)
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Re: Sorta solar kiln
« Reply #32 on: October 08, 2019, 05:51:55 PM »
It is common to have plus or minus 1/2% MC due to temperature, loss of contact with a nail, different depths, etc.

Regarding nails used as probes, predrill a hole that is a tiny bit smaller in diameter than the pin so the pin is snug.  Drill the hole about 1/4 shallower than the desired depth. using a sharp drill bit.  Then pound the nail in the last 1/4" of the way into fresh, undrilled wood.  Note that the desired depth for the average MC is usually 1/4 of the thickness, so you would not predrill 4/4 or thinner, and the predrill for 5/4 would be no more than 1/16; for 8/4, predrill 1/4 deep and then pound the nail into the 1/4 deep hole and then 1/4 solid wood; etc.

Remember that end grain dries about 20x faster than face grain, so end grain readings are not too useful for estimating the MC of the entire piece.

P.S.  VERY IMPORTANT.  Remember to pull the nails out BEFORE running across the planer, jointer, router, etc.
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Re: Sorta solar kiln
« Reply #33 on: October 08, 2019, 06:08:00 PM »
For precision, you need correct the reading for species. Temperature is a factor also. Just throwing it out there . . .
HM126

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Re: Sorta solar kiln
« Reply #34 on: October 09, 2019, 08:52:28 PM »
Hmmmm.....took readings and saw over 14% on the one that was showing 12.4% last and over 11% on the one reading 10% last....I'm wondering if this could be because I put the heater in there and the fan on top of the stack?

Shut it all down due to the cold coming tonight (22F for a low) and not wanting to pump 1500watts non stop into the kiln and have the dehumidifier freeze up.  Pulled the temp logger and saw that the little heater was keeping things VERY warm indeed.  Despite days in the low 60's the kiln was reaching as much at 110F during the day and remaining in the high 50's or low 60's at night.  Humidity at night was rising to just above 40% and at the hottest below 28%.

I'm thinking that might actually have been working pretty well for me (and I was seeing more water escape the line than before) but am also thinking it's time to bring it inside and perhaps have more warmth longer.
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Re: Sorta solar kiln
« Reply #35 on: October 11, 2019, 09:42:21 AM »
Those readings were early in the morning, yesterday after a pretty good day of warming up the kiln (with sunlight only) the readings were back to 12.4% and 9.x% (can't remember that one and didn't record).

I removed the fan, heater and dehumidifier from the box and opened it up so any moisture could escape and plan to move the wood inside this weekend (have to move it anyway because I have a big shed coming and need the room for the shed to travel to it's new home).

My plan now is to reconstruct the box in my garage but with insulation and a heat source.  My thought is to use a couple 500 watt halogens to heat the box and to keep the box small as possible.  Here are some questions I have:

1.  Would it be worth planing down the lumber to flatten it out before re-stacking and drying it more?  I had a lot of movement in some of it during the air drying (my guess is it dried too fast in this dry climate).
2.  Would two of those halogens heat up a box hot enough (box would be approx 4x4x11).
3.  Would it be best to put the fan facing down and drive the air down onto the pile instead of on the end opposite the dehumidifier?  I'd assume I'd need to place a baffle of some sort on top of the wood so the heat is driven to the sides and not the top pieces.

My thought is to place two halogens on cinder blocks at one end of the box about two feet from the end of the stack and place a baffle in front of the wood with an air gap to reduce hot spotting the end of the wood, then place the dehumidifier at the other end of the box so the wood is in the middle.  With the fan hung above the wood driving the heat down around the wood I might get the best circulation.

Once running I could turn off the heat at night and allow some cooling so the DH could do it's thing perhaps and I'd have to watch temps to ensure I don't get hotter then I want (I'm thinking 140F ought to do it but am uncertain as I recently read 150F is better for killing bugs (which I have no idea if I have or not).

Thoughts?
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Re: Sorta solar kiln
« Reply #36 on: October 11, 2019, 07:07:26 PM »
Moisture readings taken before noon are often higher than afternoon readings as the conditions in the kiln are cooler and more humid from perhaps midnight to 6AM and so the shell picks up a little moisture, that is evaporated in a few hours.  The higher moisture in the shell affects readings taken with nails or any uninsulated probes.
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Re: Sorta solar kiln
« Reply #37 on: October 12, 2019, 02:57:52 PM »
 

I had a pretty badly warped piece of the walnut (5/4) that started splitting and cupping and doing all manner of silly things before I got all the lumber stacked and stickered.  So, that piece I left in the garage and eventually split it in half, then split it the other direction (so quartered) and finally cut it into roughly 12" pieces that I thought I could flatted in the planer.  I then did just that and finally after cutting some a little more, tested MC and found 8% in the middle of the cut off one and 8% straight down into the face.  Funny that, but then the stuff I had outside was measuring around 6% (the 5/4 stuff) so the difference is there.

Anyway, I was able to flatten these in the planer and while they might not be very big at only 12" long they are all usable somewhere :D  I've restacked and stickered the now flattened pieces so they can maybe dry more but I also now feel confident that doing the same with all the big stuff will be better before final drying :)
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Re: Sorta solar kiln
« Reply #38 on: October 12, 2019, 02:59:31 PM »
lots of character just like the harvester!!!    8) 8) 8) :)
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Re: Sorta solar kiln
« Reply #39 on: October 12, 2019, 03:04:11 PM »
Yup, pretty nice figure (the board, not me) :D ;D

Added some comments

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Re: Sorta solar kiln
« Reply #40 on: October 12, 2019, 03:08:32 PM »
that much figure is going to warp and create tension with drying in any wood.  very nice!
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Re: Sorta solar kiln
« Reply #41 on: October 12, 2019, 03:10:36 PM »
that much figure is going to warp and create tension with drying in any wood.  very nice!
That I did not know!  It makes sense and explains the challenges I've had with this wood.  I figured it was just tension in the tree/logs that I was fighting and perhaps drying too fast in our high desert climate.
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Re: Sorta solar kiln
« Reply #42 on: October 12, 2019, 04:40:10 PM »
after dry, may have to joint one side, then plane the other.  the plastic is the mechanism by which you try to control the humidity and rate of drying.  more dry is not always "more better"  lol.  you can allow for more planning in thick slabs, and or just plane until you have erased the defects in the wood.  that has a ton of grain running all over from a branch.  not gonna be straight no matter what you do, but sure is interesting and pretty.  just like you @OlJarhead .   :) :) :) ;)
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Re: Sorta solar kiln
« Reply #43 on: October 12, 2019, 11:14:13 PM »
If you would like a technical explanation...
Wood is made mainly with woody cells (hollow, miniature, skinny tubes with length 100 times the diameter) that run vertically in the tree and carry liquids to the leaves.  These cells shrink and swell in diameter (thickness and width of lumber) as the moisture changes between 0% MC to around 30% MC.  Their length does not change an appreciable amount usually.

When you have swirly grain, it means that the cells (sometimes called the grain) are no longer vertical in the tree but run different directions.  Along with this swirly orientation, it means that the shrinkage and swelling of the cells in diameter cause a particular swirly region to have shrinkage and swelling along the lumber's length.  Different grain angles mean different movement characteristics- -warp- -within a piece of wood.  

The bottom line is that beautiful swirly grain in lumber means warp variations are likely.  Control is extremely difficult or impossible.
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Re: Sorta solar kiln
« Reply #44 on: October 14, 2019, 09:36:45 AM »
Thanks Guys.  My plan, with luck, is to plane all of what I have down until it's flat :D  I did manage to work the small pieces I have down to 'pretty darn' flat ;) but those were tests.  Now they can wait for use as bow ties or whatever I can find for them being so small, but the big stuff I will plane down with the router sled.  I can remove about 3/4" from them, maybe a full inch if needed.  Then, if that's not enough I'll have to cut them smaller but I do have pieces that remained fairly flat so we shall see.
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Re: Sorta solar kiln
« Reply #45 on: October 14, 2019, 12:30:05 PM »
My plan, with luck, is to plane all of what I have down until it's flat
 

Just remember that you can't plane bow or twist out of a board. You can make it thinner but it will still be bowed and/or twisted. Sometimes it's even hard to plan cup out of a board when the rollers keep pressing it flat.

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Re: Sorta solar kiln
« Reply #46 on: November 05, 2019, 09:35:09 AM »
It's been a while!  I've cleaned out the shop after getting a new storage shed to give me a place to put crap I don't want in the shop ;) and got my router planing jig and table set up.  Then finally started planing.

The walnut is down about 11% and as I mentioned before I decided to plan it flat and continue the drying from here (and possibly using some that won't need to be down at 8% or better).


 

 

 

 
It's taken some work to get the jig set up well and the right bag on the vac filter with the right dust mask etc etc but at this point most of the fine dust is going into the vacuum and not past my cheap mask (because I got a better one too) and some of these have a lot of movement and require more material to be removed but so far this is working.

Now let's hope they stay flat!  Only three done so far but I'm getting the hang of it.
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Re: Sorta solar kiln
« Reply #47 on: November 05, 2019, 11:57:21 AM »
@OlJarhead the  jig will get it flat and at low MC hope it stays that way.  what @alan gage is saying is that running it through a traditional planer will make both side follow the other but may not take the twist out.  if your slabs are fastened or shimmed so they cannot move, the top side should be flat when done.  then if you had a big enough planer it would work fine for the second side.  or just flip it over and use your router sled again on the second side.  by definition you are really jointing the surface with a sled, not planning which is i think the point Alan was making.  looking good.  lots of hard work.
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Re: Sorta solar kiln
« Reply #48 on: November 05, 2019, 02:29:36 PM »
Aha!

That makes sense, thanks!  I shim the underside, 'joint/plane' the top until it will sit flat and flip it over and do it all over again.  Once both sides will sit flat without shimming I then go back and forth doing enough on one side to make a difference, then the same on the other...sorta like milling.  The idea being to limit movement or 'mill' it out.  I had not noticed any though so decided to make one side completely flat and then flip and see how that goes.  So far so good.
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Re: Sorta solar kiln
« Reply #49 on: November 05, 2019, 05:22:58 PM »
yes, just do one side until flat with shims under it, when you flip it over, it should sit flat without shims. and then do the second side.  
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Re: Sorta solar kiln
« Reply #50 on: November 05, 2019, 11:11:43 PM »
Finished off my 3rd piece.  I noticed a very slight bit of movement in the piece overnight though (I think -- unless it wasn't quite flat after the 1st session) and shimmed it with some sand paper, finished planing/jointing and then flipped and planed the first side again just that little bit.  Lots of nice figure, which probably resulted in the slight movement.  

 

Here's hoping it settled down.  A friend of mine was big into Japanese carpentry and explained that no matter what you do it will move.  The question is, he says, can you work with the wood and what it wants to do  :D ya, not likely.  I'll stop at some point and super glaze that sucker and attach steel legs and move on ;)

 



 





 


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Re: Sorta solar kiln
« Reply #51 on: November 06, 2019, 09:10:42 AM »
I think rustic allows for a little movement, not meant to be perfect.  if you keep it you re-flatten it 3 years from now if needed.
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