DIY small kiln

[ac7112]

I'm new to lumber processing...I have access to some nice oak lumber from a local sawmill, and I'd like to set up a small kiln in my backyard to process a few hundred board feet at a time...all of the wood will be used for furniture.

I'm looking to build an insulated box, and have been thinking about using a small room dehumidifier and an electric heater to dry the wood....

Does anyone have any suggestions or construction plans for me?

Thanks

[Ianab]

I would consider building a Solar Kiln. Probably cheaper to build and run, and because of the nature of it's daily heating and cooling cycle you don't need to worry about any fancy control system.

Domestic dehumidifiers don't stand up well to the acids many woods give off as they dry, and the radiators corrode out quickly.

Ian

[Buck]

try solarkilninfo.com

[pineywoods]

I would say, build a solar kiln. cheap and works well if you are patient. I have built 2, we dry oak well enough to make flooring and cypress down to 6%. No expensive controls or electrical equipment. I find that wood dried in a solar kiln works as good or frequently better than conventional kiln drying. The only drawback is time. A solar kiln is slow, because very little drying occurs at night, but that allows the wood to stabilize.

[kelLOGg]

ac, I did just what you describe. I put it in the 2nd floor of my barn so I got by w/o building to withstand the elements. It measures about 16 x 6 x 6 with 6 in fiberglass insuluation so it is small. Attic fans provide circulation and a room de-hum removes the moisture, antomatic vents remove heat and moisture. I'm still figuring out the best way to operate it so I intervene to change the settings often. I dry only air-dried lumber to get it down to 6%. I think this is a must w/ a room dehum otherwise it will dry too fast and crack. I have heaters to raise the temp after the charge is dry to kill bugs. So far it has worked very well but I use it only a few time per year. Drying 100 - 200 bdft raises my utility bill about 10 - 20 $/mo. After all the hard work of cutting, stacking and loading the kiln it is gratifying to sit back and 'watch' the wood dry .
Bob

[jaythecelt]

I build a very small kiln using a dehumidifier and an insulated box.  Mine is about 2' wide x 10' long x 4' high.  I used foam board insulation in the interior with a dehumidifier, fan and a couple of halogen lights for heat.  I bought the plan from Darren Nelson at http://www.nelsonwoodworks.biz.  He charges $25 for a pdf file and his technical advice.  I hesitated paying $25 for something I thought I could get for free from forums like this, but he does have good advice and besides you can't blame the guy for making a buck or two from his hard work.  The pdf isn't a specific plan- after all, I'm sure anyone who is interested in wood can figure out how to build an insulated box.  Its more about the concepts and what he learned from running his own kiln.

As part of the deal he asks that you don't give away the details of the plan, so I won't do that here.  But I I think it is worth the $25, especially since I picked up the dehumidifier for free on the side of the road!  I can also tell you he warned not to over insulate the box - advice that I didn't follow closely enough.

I have the kiln outside, and I'm having a problem with the dehumidifier overheating the kiln (since I over insulated it) but it seems to work well in cooler weather.  I'm thinking of adding a vent, or some type of thermostat to shut off the dehumidifier when it gets above ~120 degrees.

I don't have a moisture meter, but I know it works because of the amount of water from the dehumidifier.  The heat also kills the powder post beetles and other creepy crawlers in the wood.