kilns for drying wood

Signed-In Members Don't See This Ad
txbatons

txbatons

Member
Joined
Jul 6, 2007
Messages
964
Location
Carrollton, Texas, USA.
I was reading in another post about using kilns for casting and it started me thinking about using them for drying green wood as well. I've been talking to our 3D art teacher at school about using the kilns in the art shop. They have two high tech kilns that have digital thingabobs and whatnots for firing in various sequences and temps. I've been wanting to try using them for green blanks.

Has anyone had any success using kilns such as these?
 
Signed-In Members Don't See This Ad
How low of a temperature can the kilns be operated at? I believe the temperatures in kilns used for pottery will be way too high. Too high a heat will increase the splitting and warping even if it does not catch the wood on fire.

Paul in AR
 
Several years ago read couple of articles on home made wood kilns. Used old refrigerators, freezers, or dishwashers that did not work anymore. You wanted the ones with metal and not glass racks, plastic covered racks were okay too. You drilled some holes, installed a light bulb and small fan. Guys were using them for drying their bowls and hollow forms.

You didn't need or use normal OEM equipment that came with those appliances except racks.

Only source that could direct you to is AAW newsletter archives, not sure of the date or article number. Not sure if will find an article in old Google groups, or Microsoft newsgroups anymore.

Unless your doing a lot of blanks at one time not sure it’s worth the effort to build a kiln. Microwave or home oven set on low, might be less work if just have one or two blanks.
 
If you cut your green wood 1" X 1" in long pieces and let dry for a few weeks and cut into blank sizes and dry a few weeks more, it really does not take all that long to dry. In microwave you can really mess the wood up, deep checking and even burn them. In a vacuum you can draw out most of the water and then finish air drying, that's quicker and easier on the wood.
What it comes down to is it does not pay to be in a big hurry. In my shop I have in different stages several batches of green wood drying. In a week or two I get my yearly supply of lilac. After I get it quartered it will be June or July before it is ready. Lilac is a slow drying wood and if I try to dry it to fast it sometimes checks to bad to use. In the begining I learned the hard way and messed up a bunch of blanks. If the wood is half dry from air drying then you can speed up the prosess. It is when the wood is so wet and dries to fast is when you have problems. In lumber mills when the logs are cut and stacked with stickers for the air to pass around the lumber it is never put in the kiln just after sawn. I sets for a while.
 
I saw an article on building a simple wall hung drying cabinet for pen blanks and other small items. It was basically a rectangular box made of wood with 2-3 shelves made from dowels or small square stock. In the bottom corner area was a light fixture and one 100 watt incadescent light bulb. In the top towards the back was a small fan like used in your computer to keep the computer cool. You basically sticker your cut blanks and place them inside. 1st week you let the fan run, no light. 2nd week light, no fan. 3rd week light and fan. Check your blanks they should be ready, if not just leave them a little longer.
 
I made a kiln using the old dishwasher plans on Russ Fairfield's pages. It works, but using only a 60 watt bulb I had some very pretty flame boxelder check badly on me... in less than a day. Temperature in the box never got above 90 degrees F. Point is, don't get in a hurry. You won't like the result.;)
 
My wifes old stove nearly ended up in a scrap yard.lucky l had a brain fart and saved it, first l cut the griller part off, then l wrapped it back up using the old tin which came off the stove l then placed a 60w globe in the top and that's it Bobs your uncle, these pictures should help.

2008124135227_100_3196.jpg


200812413531_100_3194.jpg
 
You will end up with ashes if you use the art shop kilns.
What has been shown is great for smaller pieces of wood.
A local shop that sells hardwood uses a solar kiln to dry wood. It is nothing more than a green house set-up. A south facing wall is simply clear plastic. There are a couple fans to move and remove air. Wood is stacked to allow circulation. Inside the room the temp. stays at 75 degrees above outside temps year round.
 
johncrane: Do you not use any kind of fan for air movement?

First time I tried drying green wood, I acquired an old upright freezer, used a 100watt bulb in the top, and a small fan in the bottom, with a number of air holes in the side...it got so hot with that size bulb that the moisture content was like a jungle, and the moisture caused the fan to short, with no air movement and the bulb still glowing, there was things growing that I am betting hadn't even been named yet..[:I]
 
FWIW: My wood drying 'kiln' is my garage. It is a large metal pole style building. In the summer, it gets very hot in there. My wood is stacked and stickered to allow circulation. I have an old oscillating house fan that I set to low speed and keep on all day, almost every day. Seems to work very well.
 
When I built my blank kiln I used a dorm size frige and simply placed a 100 watt bulb connected to a green house timer that controled the temp, and a muffin fan wired seperatly. I also cut a square hole in the top of the fridge and built a sliding door out of plexi glass over the hole. My schedule is as follows:

1. load the wood and use the fan only for 1 week to stabilize the moisture level, trap door completely shut

2. Turn the fan and bulb on and set temp to 70 for one week, trap door partially open

3. Turn temp to 80 for one week, trap door open even more

4. Finally bake wood at 90 for one week, trap door fully open.

One month total and completely dry with no visable checking. I have to admit that I have only done one load of local cherry burl that I cut up on my bandsaw. I am by no means an expert at this, but I now have more cherry burl than I need and the price was right. I have tested most of the pieces with my Delmhorst MM and got a reading between 6-8%. I researched this topic for what seemed like months and this was the final configuration I settled on, seems to be working fine.
 
You must log in or register to reply here.
Back
Top Bottom