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Starting to build the solar kiln

Started by btulloh, May 31, 2017, 05:14:28 PM

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btulloh

I can't get the list whittled down to where the solar kiln is at the top, so I'm getting starting anyway.  DanG the torpedoes! Full speed ahead!

It seems like some of this has been covered more than once, but I can't find it searching the forum, so I'm gonna ask:

- Is OSB ok to skin inside?  Someone said it won't hold up in the heat, but that didn't seem to be the consensus.  Would CDX work better?

- Same question for flooring.  OSB, CDX? Skin under the joists with CDX or is PT plywood a must?

- I'm planning to do lap siding on the outside and no sheathing, but put tyvek wrap under the siding.  OK?  Not Ok? 

- I'll be using fiberglass bat for both walls and floor insulation.

This thing is going to be 12'x5' inside.  That should be an appropriate size for now.  I'm trying to keep the costs down, but I don't want to compromise the function too much.  Thanks in advance for any input.

BT



HM126

ChugiakTinkerer

The VT design document recommends plywood such as CDX for the flooring, but only specs PT for the floor joists and blocking.  I doubt there would be any difference between OSB and plywood for sheathing at the anticipated temperatures.  I did find a study that compares the strengths of both after prolonged exposure to heat (ie a house fire) and OSB fares slightly better (see here).  Figure 4 shows the strength vs temp curve.  Of course the material used in that study may not be the same as you can buy today.  I'd probably go with OSB and make sure to coat it well with the rubberized paint.
Woodland Mills HM130

Tree Dan

I used OSB on the inside, and its working just fine.
I would go wider than 5' though...If your stack is 4' wide i would build it min. 6'wide inside.
Have fun with the build!
Wood Mizer LT40HD, Kubota KX71, New Holland LS150, Case TR270
6400 John Deere/with loader,General 20" planer, Stihl 880, Stihl 361, Dolmar 460, Husqvarna 50  and a few shovels,
60" and 30" Log Rite cant hooks, 2 home built Tree Spades, Homemade log splitter

btulloh

Thanks for the reply.  OSB would certainly be cheaper as long as the glue doesn't fail, the plywood probably uses the same glue, so . . .

I may decide to go wider than five feet, because it doesn't add much material and gives me more flexibility.  I use 32" packs mostly, because it works for me and my equipment and I'm low volume.  Wider still sounds better though and gives me some future options. 

Generally I will be drying stuff that's 8'6 or 10'6 so that's where I came up with the 12 foot length for the kiln.  I have a tendency to over-do the while-your-at-it's on my plans, and that can lead me to building something the size of a gymnasium if I'm not careful.  (While I'm at it, why not make it big enough for 16' lumber?  Gosh, 20' might be nice sometime.  Maybe I should go for 1500 bd ft?)  So that's how it goes.  Just trying to keep this smaller for now.

Thanks. And keep 'em coming.
HM126

jaciausa

I believe pressure treated cdx was used in the Virginia Tech Kiln Plans. Moisture is not good on OSB over a period of time.

GeneWengert-WoodDoc

Use CD-x if possible.  No need to use pressure treated sheet goods.  The plastic goes on the inside with the insulation being to the outside of the plastic.  Keeps the moisture inside from getting into the walls.  OSB will work ok but might not last as long.  The bottom of the joists can use hardware cloth to hold the insulation and keep most critters out.  Ventilate under the kiln and then PT plywood or framing is not required.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

btulloh

Thanks Gene.  Good info.

I'll be keeping an eye out for upcoming classes in my neck of the woods.  (Mid-Atlantic)
HM126

Tree Dan

For some reason i thought we were talking about the inside interior walls.
Thats where i used the OSB.
There is normaly a marking showing the Outside of the sheet, i would keep that side facing in.
As for the exterior walls I used RS pine - 1x8 , if i ever build another solar kiln I would use plywood with good paint.
Have fun with the build!
Wood Mizer LT40HD, Kubota KX71, New Holland LS150, Case TR270
6400 John Deere/with loader,General 20" planer, Stihl 880, Stihl 361, Dolmar 460, Husqvarna 50  and a few shovels,
60" and 30" Log Rite cant hooks, 2 home built Tree Spades, Homemade log splitter

btulloh

Definitely talking about the inside walls.  Sounds like cdx is a better choice for inside.  Easier to paint too, although I'm hoping to find a way to spray whatever I put on the inside.  Planning to use SYP lap siding on the exterior.
HM126

50 Acre Jim

Btulloh, checking to see what kind of progress you're making? 
Go to work?  Probably Knott.  Because I cant.

samandothers

https://sbio.vt.edu/for-the-community/extension/solar-kiln/solarKilnWorkshop/index.html

Btulloh, the link above is from a Va Tech site. Seems you may have just missed this year's session.

btulloh

Looks like I missed it.  The way things are going I might be on time for NEXT May.

The weather this week is perfect for building.  Reality keeps getting in the way.  I need a dose of Kbeitz.  He gets a lot done. 

Here's where things stand:



 

Not quite ready to run a load.   ;)  I hope to get in a couple hours work today cutting parts.  Many other less interesting things to do this week getting in my way.  Looks like the torpedoes are winning.  (How does Kbeitz get stuff done so fast?)


HM126

btulloh

By the way Jim, what is you're eager to get started on?  Get goin' already!  :)
HM126

Kbeitz

Quote from: btulloh on June 28, 2017, 10:17:09 AM
Looks like I missed it.  The way things are going I might be on time for NEXT May.

The weather this week is perfect for building.  Reality keeps getting in the way.  I need a dose of Kbeitz.  He gets a lot done. 

Here's where things stand:



Not quite ready to run a load.   ;)  I hope to get in a couple hours work today cutting parts.  Many other less interesting things to do this week getting in my way.  Looks like the torpedoes are winning.  (How does Kbeitz get stuff done so fast?)

I'm retired. I guess I have time to do things.
I don't sleep well at night if I don't get done what I have planed to do.
My problem is that I don't get one thing finished before my mind wants to do another.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

50 Acre Jim

Quote from: btulloh on June 28, 2017, 10:19:21 AM
By the way Jim, what is you're eager to get started on?  Get goin' already!  :)
Waiting on delivery of my Norwood HD36, they said it would be 4-5 weeks and that was 10 days ago.  So, I wait and I wait... 

I have to build a solar kiln too which is how I found your thread.  But I have to have a sawmill to cut the wood before I can start the build so in the meantime I'm researching.  I have the same problem as you in that I start out to build an outhouse and end up with a bus station.    :D  I want to be able to dry longer woods so I'm going to have to build something that will accommodate at least 12', maybe even 16. 

I have a killer location picked out right beside where I'm going to put the mill.  Don't want to lug that wood around anymore than is absolutely necessary. 
Go to work?  Probably Knott.  Because I cant.

btulloh

Ahhh. Makes sense, Jim.  Weeks seem like months in that scenario.  That'll be a nice machine when it gets there though.

Knowing what I know now, it would have been a good idea to build the kiln while I was waiting for the mill.  The lumber is not that big a part of the expense, so sawing it yourself isn't necessarily a big savings.  I decided to use store-bought framing lumber so I wouldn't be building a mold generator. Besides, your first lumber will probably get used for a mill shed, unless you've already got that.

I've been sawing a lot of SYP for framing lumber and I found that in the summer I don't stand a chance of keeping the mold away.  I don't really have a good place to sticker it where I can put fans on it, and I'm not sure that would solve the problem anyway.  Now I've accumulated pallets of sawn SYP and I don't want to dead stack it and put it away air dried.  So that being said, I should have built the kiln much earlier.

Another thing I learned is that I would've been way ahead to get more stuff organized before the mill got here.  Of course I had to learn most of that as I bumbled along, so I'm not sure I could have cheated the curve.  One thing I would definitely do though is build some sticker pallets before I ever started sawing lumber.  Handing the output takes a lot of time and effort.  I found out that sawing is about 10% of the overall work involved.  I think I'm one of those people that had to put their hand on the wood stove to find out what hot meant. :-[

Good luck with your mill - when it finally gets there.
HM126

50 Acre Jim

Quote from: btulloh on June 28, 2017, 05:44:35 PM
Another thing I learned is that I would've been way ahead to get more stuff organized before the mill got here.
Yes, I've been doing that as well.  Started to build a mill shed but didn't have enough lumber so I did what I could and will do the rest when the mill arrives.   I have about 20 6X8's (12' & 16') that I'm going to frame it with.  Want some beefy rafters should I decide to install a block & tackle.  Not sure I will need one but better safe than sorry, right?

Cut in a road across the mountain today so that I can bring the trees down without actually crossing any of my good roads.   So yeah, been doing what I can to get ready for when my new toy (um, tool) gets here. 
Go to work?  Probably Knott.  Because I cant.

Kbeitz

Quote from: btulloh on June 28, 2017, 05:44:35 PM

Knowing what I know now, it would have been a good idea to build the kiln while I was waiting for the mill.  The lumber is not that big a part of the expense, so sawing it yourself isn't necessarily a big savings. 

It is if you use plywood...
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

btulloh

Quote from: 50 Acre Jim on June 28, 2017, 03:56:54 PM
Quote from: btulloh on June 28, 2017, 10:19:21 AM

I have to build a solar kiln too which is how I found your thread.  But I have to have a sawmill to cut the wood before I can start the build so in the meantime I'm researching.  I have the same problem as you in that I start out to build an outhouse and end up with a bus station.    :D  I want to be able to dry longer woods so I'm going to have to build something that will accommodate at least 12', maybe even 16. 


Jim, I decided to make it 160" long like the VT design for the same reason.  I am taking a bit off the width, just to be contrary.  Mission creep: 10' should be enough - well might as well make it 12' - now that I think of it, 16' would come in handy - heck why not 40'?

If I need to dry 16' lumber, I'll have to build another kiln.  But first I need to build this one.  Limited progress this week.  I'm lucky to get a couple hours a day to work on it.  I am getting parts cut though.  Had a small generator issue one day that shut me down.  Now my lower back got tweaked and I'm on restricted duty.  I need to bush hog the edges and roads again.  Grass keeps growing.  And so forth...

HM126

btulloh

Thinking . . .

Would it be beneficial to make a hard plenum structure like this?  Bad? Ok but needless? If it's done like this, is there any reason to paint the lower surfaces black?  Use light colored paint to seal the part of the kiln that's not collecting energy? 



 
HM126

GeneWengert-WoodDoc

It is not necessary to do this with the actual collector surfaces.  It does not help to have them parallel to the roof.  What if you are one or two layers of lumber short?  What if the pile shrinks in height as it dries?  You need to fill the gap so that all the air goes through the pile and not have some go over the top.  What if you have a few extra pieces of lumber--adding them to the top would mean no air flow for them.  If you load with a fork lift, this design makes the job very critical.

As you mention, the only black painted items are the surfaces that the sun "sees."
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

fishpharmer

FYI here is a photo of ff member Pineywoods very effective version of the solar kiln.  He will have to fill in the details as I don't recall, I took this pic years ago.

Built my own band mill with the help of Forestry Forum. 
Lucas 618 with 50" slabber
WoodmizerLT-40 Super Hydraulic
Deere 5065E mfwd w/553 loader

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work. --Tom A. Edison

btulloh

Tough week for building.  Hi temps and humids.  Feels like fishfighter weather here.  I have been getting materials and cutting a lot of parts and this weeks got started with construction.  Slow going, but making progress.  Once I get the north wall stood up it should pick up speed if I get some time to work on it.

I appreciate all the input from everybody.

(Yellowhammer says he calls his the easy-bake oven.  I think I'll hang a couple pork butts in this thing and see how it comes out when I'm not running a load of lumber. ;) )



 
HM126

Florida boy

hmm pork Butts now we're talkin' . in all seriousness  I'm really looking forward to the build. I need to start mine but a pole barn is on the list first. keep us updated you know where all addicted to F.F. pics!

fishpharmer

Btulloh, you have a heck of good start there.  Won't be long till completion. 8)
Built my own band mill with the help of Forestry Forum. 
Lucas 618 with 50" slabber
WoodmizerLT-40 Super Hydraulic
Deere 5065E mfwd w/553 loader

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work. --Tom A. Edison

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