Building a Kiln

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StatProf

StatProf

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Have any of you ever built a small kiln? I was watching a video on pepper mills and the turner had a shop made kiln that he made out of an old fridge. Anyone tried anything like this? Ideas and/or plans?

Thanks,
Statprof
 
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NewLondon88

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I haven't done it, but a kiln is basically heating elements and insulation.
There are bricks that will keep heat in, I've heard them referred to as
fire brick, but who knows?
You'd want some type of temp controller and possibly some sort of thermal
cutoff. Some kilns used for ceramic firing use a material that will melt at a
certain temp to hold a switch closed. Once the temp is reached, the material
melts and stops holding the contacts together, so the heat shuts off.

I wouldn't try it with a refrigerator or any parts from one.. Those are meant
to keep things cold, so a lot of the parts and insulation are plastic.. those
wouldn't hold up well to heat. (I think..could be wrong )
 
SuperDave

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Kyle,

I have a friend that built a kiln from an old refrigerator. He dries bowl blanks, etc. (dried some 100+ Hazelnut Burl pen blanks for me in a couple days... no cracking or checking... pretty cool!).

It is quite simple, actually. Get an old 'fridge with a good seal on the door.

Drill 1" +/- holes along the top side edge and bottom side edge for air circulation.

Install a light socket in the lower portion inside the 'fridge for your heat source. (Some people start with a 40W-60W and work up from there to dry wood, others start higher and work lower, some just use one bulb).

Install a light switch on the outside of the 'fridge.

Optionally, some install one or more small computer fans to help circulate air. Others install a thermostat to turn the light/fans on and off, to maintain consistent temperature.

I will be making one for my own use in the near future.

Good luck!

D
 
NewLondon88

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SuperDave said:
Install a light socket in the lower portion inside the 'fridge for your heat source. (Some people start with a 40W-60W and work up from there to dry wood, others start higher and work lower, some just use one bulb).
Click to expand...

Ah .. when I saw kiln, I was thinking of things in the 400-500 degree range.
You're talking about a light bulb.

Sounds like more of an incubator to me.. :tongue:

but yes.. fridge could be done. I take back what I said in my first post:

.eno morf strap yna ro rotaregirfer a htiw ti yrt t'ndluow I
 
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Rifleman1776

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400-500 degrees is for cooking wood not kiln drying it. Temps like that are certain to crack your wood.
The best home kilns I have seen are simple frames covered with visquine (clear plastic sheeting). Depending on how much space you have, make the frame with the most area facing south. Have a small fan at one side for an air inlet and an opening at the other to let it out. You may want another fan inside to circulate the air.
A set-up like this, during daylight hours is always 75 degrees warmer inside than outside ambient air. They are very efficient kilns. How long it will take depends on the wood type, thickness, time of year it was cut and other variables.
 
Daniel

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I was thinking the same thing about a kiln in the 500 degree plus range. With all the talk lately about metal working, but the pepper mill reference should have snapped me back to the woodworking world.
 
penhead

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I have dried wood inside an old upright freezer. Basically, fridges/freezers are great insulation boxes. Doesn't take much to bring the heat up, even a small watt bulb will make the inside hot. It's key to note that air circulation is very important. Also, the holes to rid the box of moisture are important. Without good air venting you will grow things on the wood that are totally unidentifyable..DAMHIKT...
 
W

Wildman

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Think last year poster here showed pictures & explained how he dried pen blanks in an old stove. Any old appliance ( refrigerator, freezer, dish washer, stove) with open racks (glass shelves not so good) will work. Light (s) and a small fan, all you need to get it running.

AAW, had an article on a refrigerator kiln several years ago.

Also have been articles on building a kiln with plywood, light (s) & fan. Build a box, with a door, add vent & wire holes. Either make own racks or use already made ones. Some folks add a timer for lights & fan. Sheet goods or wood built kilns can be as small or big as you need.
 
W

Wildman

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Free water in wood evaporates readily under ambient atmosphere conditions. Removing bound water in wood cells requires more energy or time. Heat in a home made kill will provide energy needed evaporate bound water thus accelerate drying times.

Most people cut their wood into pen blanks, or rough turn other stuff before putting that wood into their kiln. So in a sense may be using both air & kiln drying methods without realizing it.

No, wouldn't stick a freshly cut piece of wet wood into a home made kiln close the door, turn on both light (s) & fan and forget it. Nor would I stick a piece of bought wood covered in wax into a home made kiln, close the door & let her rip. I would let that freshly cut wood sit around awhile before putting it into the kiln. Would remove the wax from that bought wood, before sticking it into the kiln..

When all said and done, drying wood in a home made kiln more art than science
 
follow3

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What about a food dehydrator?????

If i was drying wood that is already cut to pen blank size.... what about using a food dehydrator?

A dehydrator (at least the model I own) only gets to about 160 degrees, has racks that are totaly vented and draws fresh air in the bottom and a fan circulates it through the entire rig and out holes in the top.

In theory it should dry small pieces perfectly!
What do you all think? Is it worth an experiment? Or has someone already found out it won't work?

Steve
 
SuperDave

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I did just that several weeks ago. I had some figured Oregon White Oak extra large blanks. Put them in the wifes dehydrator over night. Did a great job and no checking on the outside of the 10 blanks. Have not turned any of them yet, so I don't know what happened on the inside, but they got nice and dry for sure!

I would go for it!


follow3 said:
If i was drying wood that is already cut to pen blank size.... what about using a food dehydrator?

A dehydrator (at least the model I own) only gets to about 160 degrees, has racks that are totaly vented and draws fresh air in the bottom and a fan circulates it through the entire rig and out holes in the top.

In theory it should dry small pieces perfectly!
What do you all think? Is it worth an experiment? Or has someone already found out it won't work?

Steve
Click to expand...
 
follow3

follow3

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Dave,

Turn or cut one of those bad boys and let us know the outcome!!!
I think if it worked for your White Oak, it should work for most anything. Oak is generally pretty hard to dry without checking.

If this method works, it could be a great tool for us to use...and relatively in-expensive... and fast!

Thanks for the input. Let us know as soon as you turn one of those blanks.

Steve

SuperDave said:
I did just that several weeks ago. I had some figured Oregon White Oak extra large blanks. Put them in the wifes dehydrator over night. Did a great job and no checking on the outside of the 10 blanks. Have not turned any of them yet, so I don't know what happened on the inside, but they got nice and dry for sure!

I would go for it!
Click to expand...
 
ldb2000

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I use a Coleman ice chest with a fish tank heater and a computer fan to dry damp blanks . As an added benifit I have covers that I can close on the vent holes and a switch for the fan , and use the setup to dry my fast dry poly finishes in just one hour per coat .
 
L

low_48

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Ah, you live in Texas. In IL, we have a perfect way to dry wood this time of year. I put a layer of blanks on top of the furnace duct trunk line. Burls and high figure stock gets placed a distance away from the furnace, easier drying species are placed closer. The blanks are gently dried because they heat up and cool down as the furnace cycles.
 
N

Nick

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One more for the mix,
I use a food dehydrator, the one I have has several shelves with screen bottoms to circulate the air from the internal fan. I have only tried it on pen blanks.
 
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