Solar Kiln

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I'm going to make an insulated solar kiln to dry out 6 -8 foot stock. Any a dvice. It's just going to be an insulated box with repurposed house windows tilted at 45 degrees (Wisconsin) and a small fan to circulate air. Any imp ortant things I need to keep in mind?
Thanks.
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On Monday, March 10, 2014 2:59:54 PM UTC-5, Michael wrote:

advice. It's just going to be an insulated box with repurposed house windo ws tilted at 45 degrees (Wisconsin) and a small fan to circulate air. Any i mportant things I need to keep in mind? Thanks.
Might not need a fan to circulate the air. Tilt the kiln about 30 degrees, make a small vent at the upper end and the warmer air should rise to and o ut the vent. Screen the vents to keep any bugs, especially wasps, out.
Sonny
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On Monday, March 10, 2014 4:00:10 PM UTC-5, Sonny wrote:

ny advice. It's just going to be an insulated box with repurposed house win dows tilted at 45 degrees (Wisconsin) and a small fan to circulate air. Any important things I need to keep in mind? Thanks.

s, make a small vent at the upper end and the warmer air should rise to and out the vent. Screen the vents to keep any bugs, especially wasps, out.

That's good advice about the wasps, especially around here. Why 30 degrees? This guy lives in Wisconsin and says 45 degrees. I'll do whatever works be st. Thanks.

https://www.youtube.com/watch?v=cTsDhCrE56U

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On Monday, March 10, 2014 5:33:47 PM UTC-5, Michael wrote:

s? This guy lives in Wisconsin and says 45 degrees. I'll do whatever works best. Thanks.
https://www.youtube.com/watch?v=cTsDhCrE56U

I didn't have the benefit of the video, so I assumed a small box-like unit, not a shed-like (larger greenhouse) unit. I was assuming you were to kiln dry small amounts (500 max bd ft) of lumber, not a bundle or two or three, as that video unit can accommodate.
I was thinking the small box-like unit would be tilted up, at one end, 30 d egrees, not the windows. I was thinking vents on each upper end, as with a greenhouse.
I did assume the windows (sashes only?) would be facing south and tilted at 45 degrees, that would be installed on the box-like unit, which would be t ilted at 30 degrees.
I was guessing at a size and design that may not require a fan for air move ment.
Sonny
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On Monday, March 10, 2014 6:10:03 PM UTC-5, Sonny wrote:

ees? This guy lives in Wisconsin and says 45 degrees. I'll do whatever work s best. Thanks.
https://www.youtube.com/watch?v=cTsDhCrE56U


t, not a shed-like (larger greenhouse) unit. I was assuming you were to ki ln dry small amounts (500 max bd ft) of lumber, not a bundle or two or thre e, as that video unit can accommodate.

degrees, not the windows. I was thinking vents on each upper end, as with a greenhouse.

at 45 degrees, that would be installed on the box-like unit, which would be tilted at 30 degrees.

vement.

He makes the claim that kiln dried wood is available faster (yes) but bette r quality? Not sure about that, but if this kiln can get the wood to 6-8 pe rcent instead of the 12-14 that you get with air drying, then that's a big win.
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On 3/10/2014 7:21 PM, Michael wrote:

You know, it's funny but a hundred years ago wood was air dried. 1 thousand years ago it was air dried.
Now we have heat in our homes... it dries out. The guy says it continues to shrink in our homes, therefore it's less than 12%..
Air dry it, acclimate it in your shop and you are good to go. Most wood stays in my rack a year or 2 before use. Except when I buy kiln dried then its a week or 2... I even get 2x4's to stabilize. I clamp them down on the rack so they finish drying b4 use, it doesn't always prevent a small twist, but it's better than taking it and using it immediately. I use 2x4's for utility grade stuff.
My tiger maple, walnut, cedar, ash, beech and cherry are all air dried.
Once you bring them in to finish drying you get down to 6-8% in the winter. Higher in the summer.
I have 2 meters a cheapy that I bring to the lumber mills, or local guys. And a lingnomat for final checking. Both agree on my final within a point or 2 so I am confident that I am not speaking out my Ass...
If you do steam bending I was told you don't want kiln dried wood.. Not sure why and not sure if its true.
--
Jeff

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*snip*

I haven't tried steam bending, but have worked with kiln and air dried versions of pine. Kiln dried wood is much more brittle. If you try flexing a small piece of kiln dried and air dried wood, the air dried will bend a bit before it breaks while the kiln dried just snaps.
Puckdropper
--
Make it to fit, don't make it fit.

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On Monday, March 10, 2014 9:49:43 PM UTC-5, Puckdropper wrote:

If it's kiln dried to 6-8 percent, it's probably going to break from lack of moisture, even after you've steamed it. Unless you're bending very think strips, maybe 1/16, kiln dried wood will not produce very good results.
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On 03/10/2014 12:59 PM, Michael wrote:

If it dries unevenly or too fast, you can always use the lumber to build a boat.
--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
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On 3/10/2014 5:50 PM, Doug Winterburn wrote:

Really, if it dries to fast it's garbage isn't it. It usually gets hardened.. And it may honeycomb.
I prefer working with air dried lumber. Especially walnut that has not been steamed... It's more beautiful.
--
Jeff

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On 3/10/2014 3:59 PM, Michael wrote:

I don't know the wood bits, but I do know solar.
The angle varies by season. Whatever angle about an hour before solar noon. You can also add reflectors to bounce more light in. Polyiso foam RMax, or reflective bubble wrap. With either you can tape/tack together.
I use corrugated panels like SunTuf when I make anything solar. That brand also has a UV shield, if you wanted to add a layer of mylar for extra insulation.
Thinking outside the box, probably too far out:
The solar heater can be separate from the wood.
http://en.wikipedia.org/wiki/Wood_drying
It seems that drying benefits by air movement:
and a small fan to circulate air. Any important things I need to keep in mind?
Larger fan and the cross section small so the air speed is higher.
I use fan forced solar hot air to heat my house during the day and I can see how solar forced air could dry wood. A mix of recyled and fresh air.
Arduino humidity/temperature:
http://playground.arduino.cc/main/DHT11Lib#.Ux5T8fldV2Q
I think keeping a relatively constant humidity may be more important than the temperature.

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On Monday, March 10, 2014 7:14:10 PM UTC-5, Jeff Thies wrote:

Thanks for the good thoughts. My goal is to keep the costs way down. I have most of the stuff laying around already, including windows, but not the 3/4 sheets of plywood or the fan. The suntuf looks like a great suggestion. I'll see where the budget is.
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On 3/11/2014 11:10 AM, Michael wrote:

Forget the 3/4", Frame it up and use the rMax polyisocyanurate for the sides. Reflective side in, you can paint the exterior if you like or cover with thin ply. The half inch ($10) should be OK:
http://www.rmax.com/downloads/DataSheets/rmp3.pdf
There is little advantage of having a higher R value as most of the heat will escape through the glazing.
The suntuf looks like a great suggestion. I'll see where the budget is.
It's very tough. Just make sure no direct sun can hit the reverse side. If so, Lowes has a similar product that doesn't have the UV shield because it does not need it. For what I do, the UV shield is important.
Also, you don't need much wood in the structure. You can frame it in with 1" or 3/4" PVC pipe. Use self tapping screws with the gasket. You will need to paint the PVC if it is exposed to UV. I've made a structure just out of the Lowes panels and 1" PVC and 2 x 2s. Very strong.
If you just need to try it out and last a season or maybe two, get the clearest 4 mil or greater poly rolled sheet. Clear poly is seldom very clear. Vinyl will be clear and seems to hold up a bit better that poly, although more expensive. Ace Hardware, I believe. Clear shower curtain liners are a lower quality vinyl but may be OK.
I'm all about cheap!
Jeff

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On Wednesday, March 12, 2014 9:43:04 AM UTC-5, Jeff Thies wrote:

Great information, Jeff! Will this rMax material hold up under rain and snow conditions, or will some kind of exterior skin be necessary?
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On 3/12/2014 11:02 AM, Michael wrote:

<snip>

It does here. The reflective side suffers more. I have raw pieces that have been outside for years. Gets dirty! I use it in all my solar. You can paint, or cover in thin ply if you wish. This stuff is stiff but it can be punctured. It's also easily repaired.
or will some kind of exterior skin be necessary?

No. You can do without one if you don't mind a little rough around the edges, so to speak.
Jeff
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On Wednesday, March 12, 2014 4:45:38 PM UTC-5, Jeff Thies wrote:

Thanks, Jeff!
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On Mon, 10 Mar 2014 12:59:54 -0700 (PDT), Michael

I remember a video on the subject, probably at the Fine Woodworking web site. The kiln operator recommended a home dehumidifier for a small kiln.
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On Tuesday, March 11, 2014 11:08:08 AM UTC-5, Jim Weisgram wrote:

y advice. It's just going to be an insulated box with repurposed house wind ows tilted at 45 degrees (Wisconsin) and a small fan to circulate air. Any important things I need to keep in mind?

I saw those too, but after casting around a little bit, I'm just going to g o for it and make a big solar kiln. It sounds like a fun project that will be very useful.
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Yes, they make a wonderful solar operated fan I use in my greenhouse. 12volt..... sounds good. you could also dry fruit..... wonder if it gets too hot too quick? warping boards? I guess you can sticker them....and cover from the sun, but circulate the air....in and out.... john
"Michael" wrote in message
I'm going to make an insulated solar kiln to dry out 6 -8 foot stock. Any advice. It's just going to be an insulated box with repurposed house windows tilted at 45 degrees (Wisconsin) and a small fan to circulate air. Any important things I need to keep in mind?
Thanks.
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"jloomis" wrote:

--------------------------------------------------------- "Michael" wrote:

-------------------------------------------------------- Norm once built a green house on NYW.
Used a modulated opening for maintaining temps.
Might want to take a look for reference ideas.
Lew
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