The solar kiln begins

[Kingcha]

I got a good start on my Solar kiln

One of the beams

 
floor framing 

 

 
The cutting table

 
The decking down and the back wall built

  

 
Thank you for the help tractor 

 
and a big thanks for the better half

  

  

We built the front wall and installed two 2x4 supports and called it good for the day.   We don't like full sun and its getting hot here today.  Tomorrow we should a 2x10 & a 3-1/4x10 and the front wall up and hopefully test fit a roof joist

Matt

[thecfarm]

That looks good. Not that it matters,what kind of wood are you using?

[Planman1954]

Good job! Keep the progress pictures coming. This is why I love the forum.

[Kingcha]

So far its all red pine lumber. All milled by the wife and I off the property.

[Andy White]

Matt
Are you patterning your kiln from Piney, or your own design? It's looking really good. I will be starting mine in a few days, so keep the pictures and descriptions coming. I love to see a plan come together.              Andy

[Kingcha]

Andy I am not sure who's design I am using.   I am sorta just winging it.  I have been reading and looking at many different designs.   Once I get the whole frame up I will then finish the design.  Its not the best approach to building but I enjoy doing it this way.   I do not plan a sealed unit like piney's.  I do not want the added cost of a dehumidifier.   I hope to run my fans off solar eventually.   I am also not concerned about drying time all that much.

[Planman1954]

Just a reminder...I found 3 dehumidifiers within a span of about a month at flea markets. People get rid of them after they finish needing them. They are EASY to find. Mine cost 5 bucks and 10 bucks! You'll need one.

[Kingcha]

I might have to experiment with using one Planman.  One ? though, I thought they consumed a lot a electricity.   I am hoping to run my fans off of solar.

[Kingcha]

Well it was a short day as the heat index it about as hot as it ever get up north.  Got a little done.  Found a mistake I had made which actually worked out in my favor.   

I also changed the plans some as I could see or envision the kiln working.   I have a 2nd beam that will give  support to my roof joist.   I lowered it about 10-12 inches which will allow me to place my fans in a better location( I hope).  I will just have to install a small support at each joist connecting it to the beam.

a few more photos

  

  

  

 

[Planman1954]

Good job on the kiln. Keep the photos coming. Others will benefit from your thread. Since I run an extension cord to my kiln from my house, I don't have an accurate way of knowing the electricity usage of the dehumidifier. It can't be much more than a small window ac unit, and since I run it only about a week at a time for a load, I didn't notice any spike in my bill.

[Kingcha]

I finished the joists/rafters I was actually short 3 so I had to fire up the mill.
Too hot to get much done but I managed to get a few hours in this morning.   You will see my one mistake in the first pic.  I forgot I was going 24" on center from the MIDDLE.  Not to worried as there will not be to much load on them, plus once I nail up my wall purlins that will beef it up some.

 
I also go my supports all in for my joists/rafters

 
A shot from the back.  I think it will work out well for my fans.  I think I will got smaller fans and just install more of them.   I will need to figure out how much air flow I need.   Any thoughts?????  14'x7'x8' high

 

taking a few days off and hopefully the heat index is down by Saturday.  I have the two sidewalls and the wall purlins to do then I will installing the interior plywood.

[WmFritz]

Nice and solid looking kiln.
I couldn't tell from the pictures... curious about insulation under the floor. Also, what angle did you go with on your solar panel?   

[Kingcha]

I did not put insulation under the floor.  I plan to put down a 2nd floor with rigid insulation and 2x2's covered by some 1/4" hardboard sheets I have and then seal it.  At first I was going to skip putting in floor insulation as I do not plan on using this year round.   Any thoughts on that????

I went with 45 degrees.

I just found some 10" fans.  They are actually radiator fans.  I  think they will work good.  I just need to figure how many I need.
matt

[Planman1954]

I would just put some roofing felt over the floor and then the 1/4" material you have on hand. Heat rises and would be escaping upward, not downward. I think we are majoring on a minor, but whatever you do, it will work. Just make it sealed on the bottom some way so heated air cannot escape. As far as the 10" fans, I don't know. I have  two 24" fans in mine to move a LOT of air through the stacks. I got them at lowes for about $35 each. They have steel blades as pineywoods recommends.

[pineywoods]

Kiln build looks good, just keep on building and taking pics. The full width doors are a real backsaver. Fans and air flow. Not critical at all. Believe it or not you will get some flow through the lumber stack with NO FANS. The roof glazing and black metal on the bottom of the rafters form a convective chimney. Hot air in this channel will rise drawing air through the stack, assuming there is a decent baffle around the stack. We found this out when the fans melted, but drying still occured, although slower. I highly recommend  installing a small cheap room de-humidifier. The current draw won't be much more than the fans. without it, you will have to vent the hot wet air to the outside every day when the sun goes down. Otherwise that moisture will condense on the underside of the glazing at night and rain down on your lumber. Not unusual to have that small de-humidifier collect a gallon of water per night out of 500 bd ft of lumber. Above all, experiment, that's how we learn...

[Kingcha]

Thanks Piney.   One of my issues is I do not have power close by.   I can run my 2 long extension cords but will get a bit of amperage lost, that said I will have to be on the lookout for a cheap dehumidifier.    I am glad to here air flow is to critical.    I look forward to experimenting.  I do plan on both upper and lower vents.

matt

[Kingcha]

Got a little more done on the kiln.   I actually had to mill more wood.   I have all the nailers for the siding done.   I have a solid top roof 3/4 done, it will end up being shingled.



  

  

  

  

  

 
I test fit the clear panels today, not sure they are right for this project but hopefully they will work out.       

Next thing is to buy some black stain, caulk and insulation.   I already have the plywood for the inside wall and the flooring.   

I have yet to work on the door design, that will come after the above is all done.

First load in the kiln will be the siding for the kiln......that I think I had better think about cutting soon.

[beenthere]

Kingcha
Your construction is looking good, and appears to be fitting up nicely.
Anxious to see how it progresses from here... and how it dries the first load before the siding is on. Or is that the point, the siding will dry in place? ;)

[Kingcha]

Thanks Beenthere, I am hoping that the interior plywood and some of the  insulation board that will be in place will be enough to let the building heat up enough to dry a small load of siding for the kiln.

matt

Hey what thickness would you all cut your siding??  It will be out of Red pine 6 or 8" wide.

[GeneWengert-WoodDoc]

Don't forget the plastic vapor barrier on the inside

[Kingcha]

Gene should I put the plastic vapor barrier between the studs and the plywood?????   or should a I just seal the wood real good.   I am thinking on the inside wall and flooring of using something like you would use on a travel  trailer roof.    My first thoughts was if I hand plastic on the studs and then put a 2nd barrier on the outside of the wall it woud not be good for my wood wall.

[Planman1954]

Typically in construction, a vapor barrior is applied on the OUTSIDE of the structure underneath the siding (styrofoam, felt, etc.) in order to prevent moisture from penetrating the wall. Then an insulation with an interior vapor barrier (paper or foil) is used. This combination of barriers creates a vapor pentration point (dewpoint) within the wall that works well. I remember from classes that if the wrong material combo is used, moisture can condense in the wall and problems result.
I've seen houses destroyed by mold when plastic was used underneath the gypsum board on the INTERIOR side of a stud wall. I would not do that.

[isawlogs]

 I have never seen a vapour barrier put on the outside of a house, always on the inside, a tyveck house wrap ( breathable barrier ) was put on the outside.

[beenthere]

Vapor barrier should be on the warm side of the insulation.
Problem arises that now AC for cooling will reverse the side of the insulation that is warm... like in the south.
But here in the north, as isawlogs says, it is on the inside because of the winter/cold.

[isawlogs]

 Never thought of those southern boys, so do you actualy put the vapour barrier on the outside of a house in the south ???

[grweldon]

Definitely not... AC in the summer isn't a problem because it tends to remove moisture from the air.  The vapor barrier is supposed to go toward the living space of the house.

[Planman1954]

Maybe everybody is misunderstanding the point I was making. There are many different materials used in walls which aide in controlling the penetration of moisture, inside and out. The outside house wrap used today has replaced impregnated asphalt (IMP) sheathing of yesterday. Styrofoam sheathing is used on the outside of house walls as well. Different combinations of materials are used in different areas of the country to control moisture penetration.

Kraft/foil backed insulation vapor barrier is only one type of moisture barrier, and IS placed on the warm side. (Check out my solar kiln build.) I was speaking of the entire wall system.

But hey, we're building a kiln here! I just used 15# felt on my kilns' outside walls and underneath the floor to control moisture (mainly from escaping so the dehumidifier can catch the moisture and expel it.)

[beenthere]

Definitely not... AC in the summer isn't a problem because it tends to remove moisture from the air.  The vapor barrier is supposed to go toward the living space of the house.

Better check that one out. The hot, humid outside air will condense on the cold wall cooled by AC, and without a vapor barrier (not talking Tyvek which isn't a vapor barrier) outside of the insulation, there will be condensation in the insulation. I'm thinking..........

[grweldon]

As far as I know it's not done that way, at least here in the south.  Vapor barrier toward the living space.  That's the method as of this date using conventional materials.  Some builders also use foil-faced rigid foam beneath or on top of the exterior sheathing, but it's not done as a vapor barrier.

[isawlogs]

  I am guessing this is going to be a coin toss.  ;D      Might be wether one takes his grits early in there mornign' or later in the evenin'   :D

[Planman1954]

Sounds like we're trying to call the insulation paper back or foil backing the "vapor barrier." I'm calling many materials vapor barriers. Each material in the wall is rated as to how much moisture is allowed through it. I'm no expert on the ratings, but it is available online.

[Handy Andy]

  Just use the kraft paper faced insulation, and put the paper side on the inside, and staple it so it doesn't slide down in the wall.  That black coating on the back side of the paper is the "vapor barrier".

[GeneWengert-WoodDoc]

The vapor barrier needs to be on the warm side, which is the inside of a solar kiln. 

In the South, it would seem that the warm side of a home is the outside of the house, but the small temperature difference in the summer means that a vapor barrier is not essential and if it is on the inside of the house, it will not be serious.  The vapor barrier is most important when the inside and outside are more than 30 F difference for long times AND the warm side is humid.  So, wintertime is the main factor in almost all cases.

In a solar kiln, or any kiln, never use batt insulation as you will get it wet (by accident, small leaks, etc.), it will lose insulation value and also get heavy and sag and fall down.  The best is closed cell, rigid board styrofoam, also called "blue board" and other names.  In a kiln that gets really hot, you also must use a product that can take the temperature, or it will melt and disappear.  The foam insulation usually cannot withstand much heat.

[Planman1954]

I give up. I'm yelling down a well. I guess kraft paper and foil will slow vapor penetration and Styrofoam won't. It's amazing a Styrofoam cup holds water. I fail to understand this discussion.

[beenthere]

Planman
There is a difference between a vapor barrier and a water proof barrier. That may be what is confusing to your thoughts.

[Okrafarmer]

Planman, can you link up to your thread about your own kiln? I am hoping to build one within the next year, if all goes well.

[Planman1954]

Here it is:

https://forestryforum.com/board/index.php/topic,50281.0.html

Build it. It works like a champ.

[Planman1954]

Thanks Beenthere. I think you are correct in my misunderstanding a lot of the posts. I was discussing permeance. I was using water and water vapor interchangeably. Permeability is the rate that water or vapor will pass through a membrane. It is expressed in perms. This relates to my earlier post of the combination of wall materials used establishing the dewpoint of penetrating moisture.

[Kingcha]

pineywoods or anyone else I have ? about attaching black metal siding on the bottom of the rafters.  Does it do a better job then just putting it on top of the pile.  Also If I do it that way I plan on leaving a gap at the top and the bottom of about a foot to allow for airflow from the fans to force it down and back thru the stack.

Thanks in advance.

Got a little done today but no pics.   I should have all the interior plywood up tomorrow as well as the insulation panels in place.   Then it will be time to coat the walls.

matt

[Planman1954]

Use metal roofing. Paint one side black, and install it under the rafters with the black painted side facing up. I left about 6" at the top and bottom....not a foot, since this allowed for more surface area to heat up. You are creating a chute that the air will flow through. Take a look at my thread  "Solar Dry Kiln Construction," and there are photos of it.

[Kingcha]

Thanks Planman, I will go with the 6" then.

matt

[Kingcha]

Well progress has been slow but I have chosen to paint the entire inside with that rubberized rood coating and I found a nice exterior flat black paint for the trusses and anything the sun will shine on.



  

  

  

 

I will get one last white coat(making it 3 coats) tomorrow and put on a 2nd coat of black until it runs out.   Thinking I will need 1-2 more gallons.   Some of the white will need to be top coated with black plus I got the metal to paint.

I almost order my fans, found some all metal one on sale.  I think I will be going with 3 14" fans.

Matt

[Kingcha]

Flooring is in, just have to get 3 coats of that rubber roofing stuff on it.   We also got the clear panels installed.


  

 

Hopefully I will have time to get the steel up tomorrow before having to head out of town.
Fans our ordered.  3 - 14 inch all metal fans.   
The goal is to start cutting the trees down for the exterior siding by Tuesday.   I think I need a little over 220 bf of siding.

I have not decided if I am going to use hinged doors or lift off doors yet, I will decide that next week.
Matt

[Planman1954]

I'm proud of it!! Lookin' good... 8)

[pineywoods]

I'm proud of it!! Lookin' good... 8)

Me too... Put a thermometer inside up near the top, then tell us how warm hot it gets.  ;D

[WDH]

You are doing good!

[Kingcha]

Thanks guys.    I have a thermometer that I use in my smoker that has an extra 2 foot lead that I was going put inside.   That way I can just plug it in when need to check the temp.

Matt

[SPD748]

Matt,

Looking great! I'm pretty stoked about getting started on mine.

Looking at your pictures, are the roof rafters 2 x 6 or 2 x 4? They look like 6's and if so, did you go with a wider board for any particular reason? I was considering using 6's thinking that it would create a larger area between the metal collector and the poly panels. I'm thinking, more area = more hot air however I'm not sure it works that way.

-lee

[Kingcha]

Thanks Lee, they are 2x6's.   I used 6's mainly for strength, originally I did not plan on attaching the metal to the bottom of the joist.  I was just going to paint everything black and put the metal on top of the stack of wood.   After reading how the others where attaching it to the joist it just made more sense.   If I had know I was doing it this way when I began I might have used 8's.

I got the metal hung this morning.   I left a 6 inch gap at the bottom and a bite larger at the top.   The way I plan on mounting my fans, they will blow down on both sides of the metal and the baffle I will install will force the air through the wood pile.

[Kingcha]

A load of logs already to go........Total of 10 not so big logs ready to be made into siding for the Kiln.

 

Screening for vents, roof insulation and the fans first thing tomorrow.

Matt

[Kingcha]

Well I got a late start again, but I still managed to what I wanted done.    The screening and roof insulation is done alone with installing the fans.  I was able to just make a wooden cleat that they hook to so they are easily removed if needed.

I also cut my 4x4 for the stacks to sit on.


  

  

 

Until I get my siding cut, dried and installed I am just going to make removable panels for the back door.   I got the pieces for 2 of them cut today but I need the right adhesive for gluing foam insulation together.   It will consist of 3 panels, the outside panels will be 4 1/2 feet wide allowing the middle panel to be 3 feet.   They will be doubled up with the inner sheets fitting inside the opening and the outer sheets 4 inches bigger to act as a stopper.

[thecfarm]

Got your first load all planned out?  :D  I suppose it might take longer because of the sun angle not being so strong now? I think you are heading towards the end of summer like I am.

[Kingcha]

My first load is some misc. stuff I have been air drying for most of the summer.  But the 2nd load we will be sawing tomorrow.   I am guessing the only wood that will see the kiln this season.

matt

[pineywoods]

The kiln looks good. Your airflow is backwards from mine, but I don't think that will make much difference. You are probably going to find that the seasons won't make a whole lot of difference. I use mine year round. With that much black sheet metal, you have heat to spare. Experiment, try different things and keep us posted on the results. 

[Kingcha]

Thanks piney.  I will be experimenting for sure and I will keep posting.   My design uses the vents instead of the dehumidifier(though I might change that).
I only plan to use mine from late April to October.

matt

[red oaks lumber]

nice looking building. the thing that stands out is the foundation. over time with the freeze and thaw, loading undloading , i'm thinking you are under supported.just my views. my wife always tells me i build stuff to last 100 years. :D

[Kingcha]

You might be right Red I did go a little lite on this set-up.   I am sitting on well drained gravel and sand though.   Truth is I think I have to move it some.  If I do I will be milling some 3x8's or bigger which will replace the blocks.    I am also not looking long term but on that note I have a 12x16 building sitting on about the same footing that is about 10 years old without much movement.     

matt

[red oaks lumber]

matt
i think replacing the blocks with solid beams will really help with movement and shifting.
again very nice looking bldg.

[Kingcha]

siding going on

 

Actually got all but the small pieces above the glass to do.

matt