iDRY Vacuum Kilns

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Solar Kiln build

Started by Kbeitz, June 11, 2017, 05:40:30 PM

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Kbeitz

Insulation ...



 

More plywood...



 



 

Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

GeneWengert-WoodDoc

Maybe you gas usage includes hot water.  I was just talking heating.  Also our house was 2x6.  We paid around $0.50 per therm.  We also had a flat fee of $17 per month, which I did not include.  Of course, there is electric for the fan too.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Ljohnsaw

Quote from: GeneWengert-WoodDoc on June 23, 2017, 04:49:07 PM
Maybe you gas usage includes hot water.  I was just talking heating.  Also our house was 2x6. We paid around $0.05 per therm.  We also had a flat fee of $17 per month, which I did not include.  Of course, there is electric for the fan too.
Now that gives me a sick feeling in my stomach! ::)

I don't have a flat rate portion but my gas rate is $1.31/therm! >:(  My gas bill now (in the summer) is for running two tankless water heaters (so just on actual use) and a gas clothes dryer was 8 therms and is $11 for last month.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

GeneWengert-WoodDoc

My error...$0.50 and not 0.05.   A typical house used 700 therms per year for heat or $350 per year for gas heat.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Kbeitz

Question...

Looking at many plans on google I see that some people fan the air in from the bottom and out the top. Other people fan the air in from top and out the bottom. What do you thing is best?  I'm thinking in from the top so it pushes the hot air down through the wood and out the bottom. I'm thinking the other way would waste all the upper heat.

So what do you all think?
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

scsmith42

Quote from: Kbeitz on June 24, 2017, 11:15:19 AM
Question...

Looking at many plans on google I see that some people fan the air in from the bottom and out the top. Other people fan the air in from top and out the bottom. What do you thing is best?  I'm thinking in from the top so it pushes the hot air down through the wood and out the bottom. I'm thinking the other way would waste all the upper heat.

So what do you all think?

All 4 of my VT Design based solar kilns have vents located directly behind the fans, and a second set of vents located at the bottom of the doors on the discharge side of the stack.

When operating a solar kiln, I tend to adjust the vent settings throughout the drying process.  With slow drying woods such as oak, at the beginning of the cycle I keep the vents closed.  There is enough leakage to allow some air exchanges w/o damaging the lumber by drying too quickly.  On the other hand, if I have a load of 4/4 pine in the kiln, then the vents will be open.

Vent position is also based upon the amount of lumber in the kiln.  If I have a half charge of a medium drying rate wood such as maple or walnut, the vents are closed.  If I have a full charge, then the vents may be cracked open a bit at the beginning of the kiln cycle.

Keeping the vents mostly closed also helps to increase the temperatures inside the kiln.  Drying at a higher RH%, higher temp allows you to dry faster but with less risk of damaging the lumber.  If you keep your vents fully open, the kiln will run at a lower temp, and with lower RH% inside, which will result in a longer drying time and potential damage to slow drying species of green lumber.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

GeneWengert-WoodDoc

Fans should blow southward across the collector space and then northward through the pile.  If you go the other way, you will bring in some fresh air at the bottom and it, with recirculated air, will go directly through the pile, and then pick up heat as it goes upward and then some of this freshly heated, drier air will be exhausted before it can do evaporation.

I agree with the comments on how to operate the vents.  In fact, with pine, you may even consider opening the main doors to increase venting, as it is high humidity that will be slowing drying the first day or two.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

rjwoelk

I dont see vapour barrier on the inside. Just wondering.
Lt15 palax wood processor,3020 JD 7120 CIH 36x72 hay shed for workshop coop tractor with a duetz for power plant

Kbeitz

Quote from: rjwoelk on June 24, 2017, 02:04:11 PM
I dont see vapour barrier on the inside. Just wondering.
The vapor barrier is on one side of the insulation.
Do I need more ?
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

I'm painting the inside with a 50/50 diesel & tar mix to get my flat black
For the inside walls.  I made a gazebo with this mix and it works great.
Within one or two weeks it's dry to the touch and it really protects the wood.
This should also help with the vapor barrier.  I have stoped working in it until
I finish making myself a metal break so I can alum cap some exposed wood parts on the kiln.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

rjwoelk

You just.need a vapour barrier on the inside to keep moisture from migratin in to the insulation. It also seals it up  from air leaks
The same as one would do for a house. But only the warm side gets it.
Lt15 palax wood processor,3020 JD 7120 CIH 36x72 hay shed for workshop coop tractor with a duetz for power plant

GeneWengert-WoodDoc

A plastic vapor barrier is better than using the insulation barrier, as the plastic "seals" the walls or floor better...unless someone puts a hole in it. 

Unlike a regular kiln where a leak in the vapor barrier means less insulation effectiveness due to wetting and then we can add a little more heat to offset this loss, in a solar kiln we do not have the option for more heat.  So, the solar kiln runs cooler with longer drying time with wet insulation.  With wood walls, decay is also a possibility.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

rjwoelk

Not sure i would use tar on the inside. Hot day you brush up against it you will be tarred. Some were i read about a black paint that was good for obsorbing heat.
Lt15 palax wood processor,3020 JD 7120 CIH 36x72 hay shed for workshop coop tractor with a duetz for power plant

Kbeitz

Quote from: rjwoelk on June 25, 2017, 04:47:21 PM
Not sure i would use tar on the inside. Hot day you brush up against it you will be tarred. Some were i read about a black paint that was good for obsorbing heat.

Once you mix 50/50 with diesel fuel and it soaks in it does not come off.
It's one of the best wood treatments that I have ever found. After two weeks
it will be dry to the touch.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

I had to stop and build a tool. One tool I did not have was a metal break.
One part of the solar kiln was not getting covered by glass so I went to
the junkyard and found two rolls of gutter alum. I needed a way to make neat
right angle bends so this is what I came up with. The last picture is a small flat
chunk of plate steel that I made my first practice bends on. It works great.



 



 



 



 



 

Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

1938farmall

K.  designed & built press brake dies for 33 years - couldn't have done better !
aka oldnorskie

Kbeitz

Quote from: 1938farmall on June 25, 2017, 07:32:50 PM
K.  designed & built press brake dies for 33 years - couldn't have done better !

Thanks...
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

Loving the brake...



 



 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

btulloh

Looks like a handy tool.  You found a good piece of steel. That bevel is the ticket.
HM126

Kbeitz

Quote from: btulloh on June 26, 2017, 08:03:04 PM
Looks like a handy tool.  You found a good piece of steel. That bevel is the ticket.

I got that last year from the junkyard. I'm thinking that is was part of a brake
or bending machine. I had to drill and tap two holes in it and it was some hard
stuff. It has three rows of magnets resisted in the bottom side.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

I liked it enough to give it a coat of paint...



 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

Working on the doors...



 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

I ran short of plywood... Wow... $22.50 a sheet.



 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Kbeitz

After seeing the price of large hinges I decided to fabricate my own.



 



 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

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