Drying Lumber

[Wismer]

I have a large amount of lumber stockpiled in the barn. It has no insulation or forced air circulation. I took a sample of it to a local sawyer to see about drying it and he says it will be hard to dry to because it is essentially like trying to suck the moisture through a pinched straw, the cells on the outside are dry but inside the wood is still not dry and will be hard to dry through the outside layer.

Doesn't make much sense to me. Any truth to it?

 

[Ianab]

What he is talking about is called case hardening. It can occur when a drying kiln is not operated correctly and the outside of the wood becomes overdry and the core is still wet.
It shouldn't happen with air drying as the process is much gentler and it's pretty much impossible to overdry the wood.

Your barn should be OK for air drying as long as there is some natural airflow to carry away the moisture as it evaporates from the wood. Slow drying is a problem with some species (like maple or pine) because it lets mould and fungus grow on the wood and stain it.

I prefer to airdry my wood outside (but under a cover/roof) for a few months where the breeze can blow through the stack and speed up the drying. Then I move it inside to complete the drying and safer long term storage.

Cheers

Ian

 

[lumberinspector]

Let me do some reading in my Dry Kiln Operators Manual I got from inspection school and I will get back to you. Not much experience on the dry end for me but I have asked a very good friend to join AS to share his knowledge. In the mean time hopefully someone with experience can answer your question.

The little I do know, I can't see where it would be a problem as some spieces I believe are air dried for quite some time before drying in a kiln.

 

[sperho]

Any truth to it?

Most likely, not in your case. If you were to have put the freshcut wood in a very hot location, forced air through it and forced the drying process too quickly, it could have casehardened at which point your lumber isn't very good for woodworking (as opposed to construction). To test for casehardening: resaw it (usually done with a bandsaw with the board on it's narrow edge - you are making the board thinner by cutting it in 2) and if it cupping immediately occurs, it may be casehardened.

Did you sticker the lumber? How long have you had it stored. Thicknesses?

Edit: Oops, I had answered not having see Ian's post. Sorry for the redundancy.

 

[lumberinspector]

Tell "Wismer" not to put any trust in his local sawyer. Lumber in a barn won't case harden. It may mold though

If the lumber is 8 -10/4 there could be a moisture gradiant problem, but a good kiln operator can deal with it.

"Ianab" is giving good info

The above is a msg I recieved from my close friend I was hoping would join AS.

Note: He has been sawing/drying for 13 years.

 

[Wismer]

Most likely, not in your case. If you were to have put the freshcut wood in a very hot location, forced air through it and forced the drying process too quickly, it could have casehardened at which point your lumber isn't very good for woodworking (as opposed to construction). To test for casehardening: resaw it (usually done with a bandsaw with the board on it's narrow edge - you are making the board thinner by cutting it in 2) and if it cupping immediately occurs, it may be casehardened.

Did you sticker the lumber? How long have you had it stored. Thicknesses?

Edit: Oops, I had answered not having see Ian's post. Sorry for the redundancy.

Thanks alot guys, Yes the lumber is stickered. It's been stored for probably 7 years, I'm not sure of the exact thickness it looks about an inch (my dad had it sawn not me)

 

[lumberinspector]

The inspection rules state that if it is an inch in thickness than you are ok but industry standard is an inch and an eighth. Gives you some room for shirnkage during drying and than room for the planing.

Just a bit of info. If your using it for yourself than its probably not that big of a deal.

 

[Wismer]

If that is the standard then i would bet it is

 

[woodshop]

Thanks alot guys, Yes the lumber is stickered. It's been stored for probably 7 years, I'm not sure of the exact thickness it looks about an inch (my dad had it sawn not me)

If I am understanding your post correctly, you say that wood is only about an inch thick... and it's been stickered for 7 years... and this guy is telling you it's still wet inside? Nonsense. After 7 years it's already as dry as it's ever going to ever get outside. Take it into a warm dry house in winter and it will dry (and shrink/move) some more though.