# Kiln for drying lumber?????



## msinc (Jan 8, 2017)

Does anyone out there use/own a kiln for drying lumber? Did you make it yourself and if you have/use one how much time does it save in the drying process? I.e., if it takes the typical one year for one inch thick rough cut boards, how long will it take in the kiln to dry the same wood to the same moisture content? 
I have been told that you can "case harden" or just dry the very outside of the wood if not done correctly. I am contemplating building a kiln and just wondering if it is worth the effort/expense compared to just sawing a lot of wood and stacking it then playing hurry up and wait. Is it better to have natural air dried wood or kiln dried? Or is there any difference if done properly? Thanks in advance for any info, it is greatly appreciated!!!


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## ClammyBallz (Apr 16, 2015)

The inch per year rule is just a general figure. You can air dry lumber in 3 months if you cut it now while the humidity level is low. When it gets down to 15%, put it in the kiln to finish it off. I used my cargo trailer as a solar kiln. Used a milk heater to keep the temp up at night, fans for circulation and a dehumidifier to pull out the moisture. During the day it got up to 135F in the stack. 2-3 days later and it was down to less than 8%.

Everything you need to know about drying wood can be found here:

https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr117.pdf
http://sbisrvntweb.uqac.ca/archivage/030108539.pdf


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## pintodeluxe (Sep 12, 2010)

I have a shed kiln that I built and use frequently. It was featured in the May/June 2017 issue of Woodworker's Journal. You could order a back issue if you're interested. The article details the construction and key equipment needed to build a dehumidification kiln.

I find the process quite interesting, and recommend it to anyone using much lumber. A shed kiln will pay for itself in no time.

Air dried, then kiln dried is my preference to limit damage to the lumber.


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## msinc (Jan 8, 2017)

Thanks fellas for the info!!!!


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## firefighterontheside (Apr 26, 2013)

I will be building a solar kiln soon. As it sounds, it uses the sun to heat up the wood during the day and has a fan to move the air. At night the fan stops and it cools down in the kiln. This prevents case hardening, but I will airdry down to about 15% and then move to the kiln to finish. The difference between air and kiln drying is that air drying usually only gets down to around 12% depending on location. To use hardwoods indoors, you're supposed to get it down to around 7% first.


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## msinc (Jan 8, 2017)

> I will be building a solar kiln soon. As it sounds, it uses the sun to heat up the wood during the day and has a fan to move the air. At night the fan stops and it cools down in the kiln. This prevents case hardening, but I will airdry down to about 15% and then move to the kiln to finish. The difference between air and kiln drying is that air drying usually only gets down to around 12% depending on location. To use hardwoods indoors, you're supposed to get it down to around 7% first.
> 
> - firefighterontheside


12% is pretty good for air drying…it is my understanding, from some local guys that dry their own wood, that around these parts 17% is about as good as you can get. I had a giant "solar" kiln…my steel building. It was just a storage building that was a shell. The sun would beat on it and it would get plenty warm. I was able to get some wood down to 6% and it took almost a year. But, I ran power to the building now and insulation and finished the inside and it's my new and much needed larger shop. I figure this time I will go ahead and build a purpose designed kiln with maybe a lean to on one side for air drying.


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## Tony1212 (Aug 26, 2013)

I'm using a "solar kiln" i.e. the back of my GMC Suburban.

Back in March, I picked up some cedar from the home store and I could literally squeeze water out of some of the boards. I just checked it last weekend and it was all much better. I'm not ready to start that project, so I haven't taken the moisture meter to it yet.

The Suburban sits outside my garage and is in the sun all day long. I thought about putting small fans in there, but I never got around to it. I had some moisture issues in there before, so it already has a bunch of tube socks filled with cat litter to absorb moisture.

The cedar is to build doors for my shed. Once I get them built, I plan to turn a part of my shed into a mini kiln with a space heater and some box fans.


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