Dry wood in kitchen oven?

[Mathias]

I'm a woodworker that has christmas projects (presents) to make. I've got some quarter saw oak I've had air drying for a year. I was wondering how to go about drying (temp., length on time, etc.) pieces small enough to fit in the oven since I don't have a kiln.

[woodmills1]

I dried some cookies in an oven, using warm setting

weigh the piece first then after say 15 minutes, take it out when it stops losing weight.

[Ianab]

You could, but if you just bring the air dried wood inside and sticker it someplace out of the way for a month it will dry to match the enviroment inside your house, and that will be the correct moisture content for working with.

Stacking some in an attic space or spare room will work fine. As the wood is reasonably dry then you wont have any big amount of water given off to cause problems inside.

An oven could actually over dry the wood, then you will have movement problems as it gains moisture from the air.

Ian

[Meadows Miller]

Gday

Mathias I dont see why not it would take alot of obsevation and regular checking to make sure your not over doing it ;) what size stock is it 1" 1 1/2"  or 2' thick and how long ? also if it is 1"  it should be at about equilibrium about 20 to 25% Emc after 12 months  ;)Is your oven fan forced ? Ifso Id start by placing a tray with some water in it to kep some humidity in the oven to equlize the mc in the timber  and start out at 100 to 110 f  for the first 1 to 2 hours taking the tray out within that time then after 2 hrs take it upto 150 to 180max f then run at that for about 3 hrs .it would be one of thoes suck it and see things  ;) ;D You could go hotter if you wanted but js aslong as you arnt seeing any fine cheaking or ckeaking atall coming up in the timber  ;)

I used to run kilns at at a large sawmill we only used to use the oven to get a baseline for what was going on in the kiln and in the yard as you would cut 2 sample boards so they would weigh the same weight one would go in the kiln after being air dryed in the yard to Emc then you would throw the other in the oven and cook the hell outa it for a hour or so at 300+f to get it below emc .as moisture meters wont give you an accurate reading above about 18 to 20%mc .you would let it cool down then do your reading once you got it down to the desired mc you just took the over board out of the kiln twice a day and weighed it un till it mached the oven sample board  too easy

You could do it the other way around if you have access to a set of fine scales as you do the weight in revese two the same at the start and the one when you finish the oven dryed boards shoud weigh in from 10 to 12 % lighter depeding on how much freewater was in the timber at the start if it as you are only trying to remove the bound water when getting below 18%mc

It will work you just have to be gentle with it mate  ;) ;D if you want to do a test run only run a couple of boards at a time and take down some notes  ??? :P ;) ;D


Reguards Chris

[tomtrees]

Hi Ianab or any one that can help

I have read this post because I need some advice on drying and hope you may help.

I have just got a mill and now have some nice oak drying out side. It was from a tree that had been proped up in another tree and died standind up with no contact at ground level except the roots. It must have stood like that for maybe 8 years.

I milled it up and it has been outside for 9 months now. It is 2 inches thick.I dont have access to a kiln and would like to bring it inside for some shelves etc. It is at 20% with my electronic tester.

My question is dose wood have to go into a kiln to reach the MC of my house. I know it would be quicker in a kiln but if I brought it into the house would the end result would be the same?

Can I start to make stuff in the house with it and let it dry in place?

Tom

[beenthere]

tomtrees
The wood will reach equilibrium in your house. If... it is stickered so air can move around both faces of the boards, and kept long enough, and the house conditions are the lowest you would expect (like a heated house during the cold months).

Outside, these past 9 months, the conditions may not have been as dry as they will be in the house at this time.

[ellmoe]

Tom,

  You can bring you wood inside and it will dry to the MC of your house. It does not need a kiln. However, you might bring in insects with the lumber that a kiln will normally kill. At 20% you will continue to have shrinkage. Depending on the project you might be able to use the wood now, but expect some movement in the lumber.

[Dodgy Loner]

Tom, there are many of us who mill our own lumber and air-dry it, without using a kiln.  I have brought lumber to my attic to help it dry out, and before I install flooring or paneling, I always let it sit inside for a week or two.  However, for something simple like shelved, I just keep the lumber outside in a covered shelter, and bring it straight into my shop.  I've never had problems with shrinkage or warping, but I do not use my lumber until it is below 12% moisture content.

To answer your question, wood will reach an equilibrium with its environment.  It doesn't matter if the wood starts out sopping wet or bone dry, it will eventually reach a point where it is stable.  Wood that is kiln-dried to 6% moisture will move more than wood that is air-dried to 12% moisture content if the equilibrium moisture content in your home is 10% and the wood is not given time to acclimate.

[Ianab]

"My question is dose wood have to go into a kiln to reach the MC of my house. I know it would be quicker in a kiln but if I brought it into the house would the end result would be the same?"

What the others have said. If you bring you 20% wood inside now and sticker it in a spare room or attic it will continue to dry and be ready to use in a few months. Wood will loose or gain mositure to match it's environment. When it does it will shrink or expand

A quick test is to measure some wood inside your house, thats been there for a year or more. It will be at equlibrium with the air in your house, although that depends on the season. The 8% number seems to be a good average for the US because of the central heating and (mostly) dry climate. I work on about 12% here in NZ, humid climate. The closer you can get the wood to equlibrium the more stable it will be once it's in place.

20% will move a LOT as it dries down to 8%, and if the grain isn't even, it wont shrink evenly and you may get all sorts of warping going on. While the wood is rough sawn you still have the chance to mill out those variations when you joint and plane it. If you get it down to 10%, movement will be minimal, and may be within normal seasonal variations.

As an aside, if we import US kiln dried hardwoods to NZ it is generally pulled out of the container and stickered for a month or so -to GAIN moisture so it's stable in our climate. Build furniture from 8% wood and put it in a 14% enviroment and you have all sorts of problems.

Ian

[Dodgy Loner]

The moisuture content in my home ranges from 9% in the winter to 12% in the summer, so once it reaches 12%, it's good to go.  I've used would that was at 14% moisture in furniture before with no problems, but I prefer 10-12% for my area.  In other parts of the U.S., 6-8% moisture inside is normal.  We live in a humid area .  Not sure what the normal moisture content in France would be.  Best way to find out is to use your moisture meter to determine the moisture content of some of the wood that's already in your home (preferably oak, since that's what you're drying). 

[Meadows Miller]

Gday

When I ran the kilns id try and findout where the timber was going and taylor each charge to suit where it was going alota fun with charges of 40mbft  ;) eg Melbourne was winter 11 to 18% emc summer was 8 to 13 depending on the situation  ;)

If you wanted to you cold get a print out of the EMCs in most areas around your country by getting in touch with your local wood science or timber industry training center which will give you the yearly average Mc and the avererage Mc for each season  ;) ;D

Reguards Chris

[tomtrees]

Great feed back thanks.

I just measured the MC in the house. I am getting readings of 14 to 15 MC in Oak and pine around the house, it is suprissingly heigh. Altough we are in winter here and I am in the north of France(mostly wet and cold and near the sea).
It seems really low in some places over in the US, we seem to be closser to NZ in humidity. (I went to Main in the US once and there it must be a bit wetter than 8% MC though).

I think I am going to sticker the wood in a spare room for a while, this seems to be the consensus of opinion.(and watch out for bugs )

[Ianab]

Good plan.

If 15% is your equlibrium then you are close to dry already  ;)

Ian

[Gary_C]

Just a little caution. Oak is one of the most difficult woods to dry. It generally will take a year to air dry per inch of thickness. Since you have two inch thick oak, it will take some time after you get it into the house to dry to equilibrium moisture content.

Also your moisture meter is reading the surface moisture content only. You better either drive some pins in deeper or resaw a small piece to check the moisture in the middle of the boards. I would expect the centers to be much wetter than the surface.

You can have some big problems if you resaw that two inch thick oak into small pieces. Expect a lot of movement if that wood is not uniformly at equilibrium moisture content.

[tomtrees]

What would you say then Gary C, 3 months in the house?

I would like to resaw to make 1 Inch boards for skirting boards.

[Gary_C]

I expect you will have problems resawing that two inch thick oak no matter how long you would air dry it. Even two years of air drying after you put it into the house may not be enough.

It's difficult to get two inch thick oak down to uniform moisture content even in a kiln dryer.

But you should try a test piece and see. Resaw a piece and check the moisture content inside. Then try to sticker the wood and let it dry again on stickers with weights on top of the stack. Then you may have to just use only the pieces that don't move.

Try it and see what happens on some test boards. But I do expect you will get a lot of cupping when you expose that wetter face. 

[Norm]

I have to agree with Gary on this. If it's white oak the best way is to mill it to 1" originally and not try to take 2" and resaw it. If it's red oak you may get away with it but I'd still expect some movement after resawing.

I'm not a fan of taking thick stock and resawing into thin stock no matter what the wood is. Some of the more stable varieties you can but many like in the oak family it is just asking for trouble. On the other hand I think you'll have the best luck with the method stated here if you give it a try. Do a couple of pieces and see if it moves after resawing.

[thecfarm]

This thread remind me what my Grandmother use to do.She would put firewood in the oven to dry it so when she was baking she would have better control over the heat and knew how much heat it would produce.

[tomtrees]

Hi Norm

I have started to read around the subject now and am begining to understand the problem, interseting you would mill directly into 1 inch this must be one of those ruls of thumb.