How hot should it be

Not too hot. I just read recently somewhere ( though I can’t recall where) that around 100F is sufficient. The key to drying wood in a kiln is moisture removal, therefore air circulation. Also, you don’t want to dry too fast. Too fast and the wood will check or honeycomb. Not enough air circulation and the wood may mold. So, it’s a balance between heat which helps to remove moisture and air circulation which carries it away.

I think much depends on what kind of wood you are drying too. It’s an art. Ring porous woods will dry faster through the ends, therefore prone to checking and honeycombing through too fast drying so these probably need to be sealed on the ends.

Having said that, don’t take my word for it – I’ve never dried wood in a kiln – only air drying and there I keep the wood in the shade but well ventilated. I dry mainly pines and NZ beech. The NZ beech needs very slow drying. The pines are mainly susceptible to growing molds in a high moisture environment but dry relatively quickly even at room temperature.

-- If you can't joint it, bead it!

around 100 f is pretty typical, all the things daltxguy are right on. With decent ventilation and temp you can dry it well in 30 days or so.

-- Power tools put us ahead of the monkeys

Thanks Daltxguy and Nomad for your input. We are new to trying this so any information is a big help. 100F should not be hard to reach in the greenhouse. We are using a wood burning outside heating unit that provides lots of btu’s. Air circulation will be buy about 4 or 5 fans. I will let you know how it turns out.

-- Guy Kroll www.thelandsathillsidefarms.org

Drying wood in a kiln is a combination of both humidity and temperature, not just temperature. Google “Drying Hardwood Lumber”. That is a good resource and you will learn a lot about drying wood.

-- Wood-Mizer LT15

Here is a link to the best site on the Internet about solar kilns, plans to build one, how to use one, and construction photos.

http://woodscience.vt.edu/about/extension/vtsolar_kiln/

You can also google “Virginia tech solar kiln” and find more information.

-- Hal, Tennessee http://www.first285.com

Guy, I’m a kiln operator. I second WDH and Hal’s advice re Gene Wengert’s “Drying Hardwood Lumber” manual as well as the Virginia Tech solor kiln manual.

Drying rates, temps, and RH% varies depending upon the species, thickness and initial moisture content of the lumber. 100F as a starting temp is acceptable for certain fast drying species, but is too hot for slow drying species such as oak, especially thick oak.

What species and thickness are you planning to dry, and will you be going straight from the sawmill into the kiln or air drying first?

-- Scott, North Carolina, www.quartersawnoak.com

Thanks to everyone for all the good information. Scott I will be drying, Hemlock, Cherry, Maple, Oak, Ash, Walnut and Pine along with some Spruce. Thickness will be mostly 1 1/4 inch with some thicker stock, 2 to 3 inches. Yes it will be going straiight from the sawmill to the klin ( just a couple of days air drying ).

Scott if 100 F is to hot for slow drying species, do you have a temp you would recommend that would be a good average for all wood.

-- Guy Kroll www.thelandsathillsidefarms.org