has anyone built a small kiln

[jonnyfontaine]

hi i have a slab of really nice curly redwood that i was gonna cut into billets to be used in building a guitar, and as soon as i cut the wood i noticed that the center was soaking wet, i was told the wood had air dried for several years but i guess it wasn't so true... so now i want to try to dry this wood as quick as possible, but also as safe (for the wood) as possible as i don't want this highly figured wood to ruin... right now the wood is just stickered in the house, but a co-worker told me about how supposedly you can build a small "kiln" with a 150w light bulb to dry pieces this size, 20" x 8" x 2"... by basically building a small box with a fan and this light bulb set to a thermostat... does anyone know anything about this, or is this idea just pretty out there? any and all advice, input would be appreciated thanks, jonny

 

[bitbight]

Jonny,

Have you thought about the possibility of a food dehydrator. There are schematics and plans on the web for building these things. You should be able to modify them for your purposes. I have seen some that use light bulbs and a thermostat to control the temperature. Might be far out there but it might also work.

 

[steviegwood]

You may even try using your oven on your stove to help quicken the drying time. You can control the temp and time in the oven. Just a suggestion. Steve

 

[Mike Davis]

Maybe use a room dehumidifier to get most of the way then add a little heat to finish it off?

 

[CarvedTones]

If you got it from a reputable wood supplier I would contact them before doing anything else. If you paid for dry, ready to use wood and got something else, they should help remedy the situation. If you try to dry it and have troubles, that won't be their fault.

 

[Pokey]

I think that Andy has good advice. To respond to your question, I built a kiln which works much the way you described. Mine is 8 feet long and will hold about 450 BD feet. I have two light bulbs for heat and a dehumidifier to take the water out. It works very well with boards. If you build a kiln for your boards, be sure to not take too much water out of the material too fast. To give you an idea of the rate of removal, 5/4 White Oak water removal should be limited to .0031 pints of water per board foot per hour.The instructions that I have and the plans are in the #92 June 2002 Issue of American Woodworker.

 

[scsmith42]

HI Jonny.

Ditto Andy's and Pokey's advice.

Due to the thickness of your slab, as well as the fact that it's probably dry on the outside, I would avoid placing it in the oven at all costs.

All: One thing to keep in mind when using fans to blow air across your wood stacks, is to avoid having too high of a current. The specific CFM varies per species, but in general an airflow in the 300 CFM range across the boards is about right. If you have too much air flow, you will dry the shell of the wood too quickly and damage it, and if your wood is very green too little air flow will cause it to mold.

In my kiln, I have special instruments to measure the airflow (HVAC techs usually have these same instruments), but I've been told (haven't checked myself though) that a 300 CFM air flow measured on the outflow side of the boards will cause a handkerchief to deflect around 1 - 2".

If it were me, and I could not return the wood, I would check the shell and core MC% with a meter. If the core is below 25%, I would place the board on stickers in my attic for a month or so, and you should be fine.

If you need me to, I can check into the maximum drying rate for Redwood when I get back to the farm this weekend.

Scott

 

[CarvedTones]

One reason I recommended not trying to dry it unless you have no alternative is that my experience with trying to dry wood has been mixed. I have some curly holly - not the grain, the boards themsleves - . Fortunately my intended use requires very small pieces, so it isn't a total loss.

 

[jonnyfontaine]

yeah unfortunately i bought the wood from an individual off ebay... so i can't really get back to the guy about the wood... but at work we have a "drying room" that is just a sealed up free standing room with a dehumidifier in it, but that's really for storing already dried wood... i searched the internet and could not find any plans for a kiln like described, and unfortunately i don't have the magazine mentioned in a previous post... if building a kiln i imagine it would only need to be about 2' deep by 1' tall by maybe 1' wide... does anyone have an idea of how to lay this out? thanks