DIY Kilns solar or other

[stevecater]

In my area there is nobody that I know of that offers kiln drying for small batches (1000-2000BF). This has me seriously thinking of building either some sort of solar or hybrid kiln in my back yard for ocasional use.
I have anohter issue as well as drying which is sterilization. I have 5000bfm of pine that has been strictly air drying for year and I started milling some for an outdoor project (its now at 14% or less) and discovered old house boring larva just under the bark on many boards. I would LOVE to be able to heat treat the wood as recommended to 133deg to kill the bugs rather than risk infestation of my soffits and maybe my whole house!!!

My thoughts were to build something like the Virginia tech solar kiln and add a heater so that I could close off the vents, crank it up to 160deg for a number of hours to sterilize then proceed to dry either by solar or maybe by electric heat/dehumidification.

My location probably will have partial shade due to close proximit trees as well so another reason I thought to add a heater.

Anyone built kins here?

One article I read suggests if adding suplimental heat, solar may be counterproductive since the collector area will have a high heat loss when the sun is not shining (makes sense I guess).

Maybe the VA tech design but insulate the roof either with or without the transparent panels so its low heat loss but convertible to solar?

TIA for any suggestions.

[James White]

Steve,

Because I live in Ct and needed to use the kiln during the winter. I built a version of this kiln. I dried 600 BF of red oak with no trouble. I also used the same dehumidifier all summer for my house. So no damage so far. I have the least lease expensive Gold Star/LG 50 pint from WalMart. I was able to get the temp up to 140F and the dehumidifier was still extracting water at that temperature. You need to insulate very well and get the whole structure as airtight as you can. The heat all came from the dehumidifier and fan motors. I only used supplemental heat at the initial start up. I don't think that was even needed.

http://owic.oregonstate.edu/pubs/dhkilns.pdf

James

[Alan Schaffter]

In my area there is nobody that I know of that offers kiln drying for small batches (1000-2000BF). This has me seriously thinking of building either some sort of solar or hybrid kiln in my back yard for occasional use.
I have another issue as well as drying which is sterilization. I have 5000bfm of pine that has been strictly air drying for year and I started milling some for an outdoor project (its now at 14% or less) and discovered old house boring larva just under the bark on many boards. I would LOVE to be able to heat treat the wood as recommended to 133deg to kill the bugs rather than risk infestation of my soffits and maybe my whole house!!!

My thoughts were to build something like the Virginia tech solar kiln and add a heater so that I could close off the vents, crank it up to 160deg for a number of hours to sterilize then proceed to dry either by solar or maybe by electric heat/dehumidification.

My location probably will have partial shade due to close proximit trees as well so another reason I thought to add a heater.

Anyone built kins here?

One article I read suggests if adding supplemental heat, solar may be counterproductive since the collector area will have a high heat loss when the sun is not shining (makes sense I guess).

Maybe the VA tech design but insulate the roof either with or without the transparent panels so its low heat loss but convertible to solar?

TIA for any suggestions.

I have done considerable research on the VA Tech and other solar kilns. The first thing you need to know, is that most are designed to dry only around 1000 bdft. The second thing is that drying wood in a solar kiln is not a load and forget process. Unless you fit it with thermostats and humidistats, automatically operated fans and dampers, etc., and even then you need to constantly monitor measure moisture content and adjust the drying rate based on the species you are drying. If you don't, then you risk a number of possible problems including warping, case hardening, etc. This also means that you must be careful of the max temp in the kiln needed to kill bugs. As you likely discovered all the information- volumes of info (articles, pdf USDA pubs, etc.) on air and solar kiln drying wood is available on the VA Tech website and the USDA Forest Service, Forest Products Laboratory websites. Much of the authoritative USDA stuff has been authored or co-authored by Dr. Eugene Wengert who directed one of the USDA labs (U. Wisc) and is arguably the guru of drying wood- just Google him.