Dealing with humidity

[tablesawtom]

Several interesting things have popped up lately that are causing me to write this.

I was over on the Sawmill Creek Forum yesterday. I don't go there often but that is a different story. Anyway I was in the sawmill section on air dried virus kiln dried wood and the talk was about relative humidity.

I was over at friends house the other day and he had just bought a pile of red oak from a local saw mill. It had been kiln dried but stored in a in an unheated steel building that had a cement floor.

Anyway he had about 150 BF and it made a pile about 3 feet wide and 2 feet high and it was setting on the basement ( cement ) floor. He made the comment that he couldn't start on his project for about two weeks while his pile acclimated to the humidity of his house. I said something and he looked a me aghast. He said don't you know this, it has been written about in magazines and books that tell all about getting humidity equalized before starting.

I think that this is an old wives tell, but from a certain point of view. I do not know about all the different parts of the country but I can assure that the humidity in the basement of a home in Iowa, in any season is different from the humidity in the living quarters. My wife has a since of humor, but she would quickly loose it if I tried to store a pile of lumber in the dinning room.

The top layer would maybe equalize, but I doubt if any in the middle or bottom would.

I could write pages on color matching and selecting the best grains to have show per sizes and so on but that is not where I want to go. I do start right away cutting the different parts. Usually this is the messiest part and depending on time, only needs to be cleaned up once. There are always smaller messes.

Again, where and how you by, depends on where you live but usually I buy skip planed wood that is kiln dried and is between 15/16 to 7/8s thick from the local saw mill. Usually I rough cut my pieces 1/4 inches wider and a couple inches longer. If I put pressure on the board correctly both in and out of the planner I don't have to worry about planner snipe.

I like to somewhat flatten the board on the jointer, and then run it through the planner. In other words I try to work all four sides of the piece leaving it large all the way around. I mark it as to what detail it is because down the road I won't remember. I then put a small hook in the end and hang it on a clothes line that is stretched in an out of the way place in the room. This allows the piece to take on or give off humidity equally from all 4 sides at once. It also allows any stress in the wood time to be released and find its own equal state.

With the business of living and dividing all my time between much I find that by the time I am able to get back to my project my wood is pretty stable.

I also avoid the law that says any flat surface will attract stuff.

It works for me, it might work for you, To others, I am sorry that your world is still flat. My friends world is still flat.

Tom

[Axehandle]

Do you ground your dust collection system?

That is where this thread is going I think.

Myself, I don't fuss about it to much. My shop is outside and unconditioned. That is the only place I can work and it the only place the wood can acclimate to.

There are no other options. I work the wood. I stick it in the house. For me, it is a moot point. Others, professionals perhaps, it may matter more.

[Yetloh]

tablesawtom said:

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but she would quickly loose it if I tried to store a pile of lumber in the dinning room.

The top layer would maybe equalize, but I doubt if any in the middle or bottom would.

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Ah, but the secret is that the lumber must be in stick, although it seems unlikely that this would make it more acceptable to you wife. However, I did once manage to get away with stacking some wood behind the sofa for a week or two, not sure it made any difference to the finished piece though!

More seriously, I am inclined to agree that short term acclimatisation to allow stresses to be released is more necessary. So far as moisture is concerned, in the short term I do think it is worthwhile keeping sawn boards in a way that allows air ti circulate during the making process.

Jim

[Robert Adams]

Our humidity outside swings up and down quite a bit as does the humidity inside. Say when the temp is nice the windows are open for days and the humidity is 80% or more at times then it gets hot and crank the ac and it drops to below 50% if you are lucky.
Winter it's usually more humid inside than in summer. (Need a dehumidifier). More cooking inside since its cooler etc and no ac to take the moisture out.


I have found that properly dried lumber is way way more important than worrying about humidity etc. I have gotten so much case hardened lumber from all suppliers it isn't funny. They are trying to get lumber out of the kiln quicker to increase profits due to less energy used that the quality is crap.
I never have a problem with air dried lumber. Kiln dried red oak is the worst to work with when it comes to honeycomb in and case hardening.

In short just get the lumber and build it. And don't prep boards ahead of time for something prep it and assemble now and you won't have any issues. Milwaukee it and let it sit you will be milling more lumber to replace the warped stuff you milled last week.

[tablesawtom]

This post has nothing to do with dust collection. Cleaning up the mess is about cutting boards from long boards to shorter boards with a circular saw and straight line cuts on a sled with no overhead dust collection. It is, and I wish it weren't about a 20 % scrap rate with all the 1 inch wide strips? and drop off that are left over. All of that needs to be cleaned up removed from the shop.
AM I knocking dust collection? o I have several. 2 hp on my table saw and jointer. No blast gates .It does a wonderful job on the jointer. On my 25 year old cabinet saw 50% on a good day.

As far as sticking the pile I agree with you Jim. But in my friends case he was acting on the information as he understood it and his was not stickered. And then there are those who will argue kiln dried doesn't need to be stickered. Then there should be air flowing through the pile. And I agree with this but it should be so that there is air movement but that it couldn't really be felt. But with this information there are some that will put a window fan on the wood and turn it on full blast.

As far as my wife goes, she would go along with it for the short time.

Quote:

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More seriously, I am inclined to agree that short term acclimatisation to allow stresses to be released is more necessary. So far as moisture is concerned, in the short term I do think it is worthwhile keeping sawn boards in a way that allows air ti circulate during the making process

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I think that Jim understands what I am trying to say. I just built a mantel for the fire place. Pictures can be seen , My latest project I believe it is. anyway I bought a 16 foot piece of red oak from a friend who had it in his barn for 3 or 4 years, He said it was kiln dried. Anyway We cut the one piece off to a length right in the barn, I will skip the details but the top of the mantel !2 inch wide I planned on both sided to almost 3/4 and then ran it through a drum sander a couple of times on both sides.

The other piece I cut down to 5 1/2 wide. The wife wanted the outside of the mantel to stay rough sawn. I wanted a smooth surface to work with on the inside and also I wanted to lighten it up weight wise. So I planned only one side removing about 3/16th or more. Because both were over 6 feet long, They were stood up ( almost straight up) on end over night. In the morning the top piece was still straight and still is 3 weeks later. The 5 inch piece was bowed at least one inch if not more. The way I did the mantel I was able to pull the bow out so no problem.

Why the bow? It was the same board from the same place. The other piece of the board which is about 6 inches wide nothing was done to it and it is still straight also. Again why the bow.

Does acclimatizing the wood hold water or is it just a wives tail? Is there anything wrong with acclimatizing the wood? And are there better ways of doing things .

Quote:

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More seriously, I am inclined to agree that short term acclimatisation to allow stresses to be released is more necessary. So far as moisture is concerned, in the short term I do think it is worthwhile keeping sawn boards in a way that allows air ti circulate during the making process

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I think Jim's understanding of what it wrote is spot on. I have had great success doing it the way I do and believe me it has taken several years to arrive here. Hanging works and the materal tends to stay right down the road.

Just passing it on.

Tom

[Axehandle]

Tom, I was being tongue in cheek with the dust collection comment. I just think there is going to be widespread views on letting your lumber acclimate to certain climates before you start working it.

I think Robert Adams hit the nail on the head with how much moisture your lumber has initially. Or to put another way, how well it was dried in the kiln or how long it has air dried. This is more important I think.

[Bibliophile 13]

Most of the USA east of the Rockies has extreme changes in humidity over the seasons. My lumber storage is not climate-controlled, but my workshop is. I often bring in wood from a 90% humidity environment to a 60% humidity environment. Yet I don't think I've ever encountered a wood movement problem in my shop that I could definitely chalk up to not letting the wood acclimate. Much more common is wood distorting after it has been cut to length and surfaced, which can and has happened with wood I've had indoors for a long time.

Regardless, if your wood is stacked in a solid pile and not stickered, it's going to take a heck of a long time for the wood in the center of the pile to acclimate to the environment.

[Arlin Eastman]

Tom

This is my view.

If after using a moisture meter and it is under 12% I say cut it. I do know of several individuals locally who bring it in, cut it and then let that lay over night so any tension will release or whatever they told me, but it was not about the MC or Moisture Content.

If he did not have it stickered while laying on the cement floor I would think that would cause drying problems.

But in my defense I do not know much about it except what I either read or what I have been told or last what I might remember but mixed up in my head.

Arlin

[AHill]

I live in a wickedly dry environment (the high desert in southern California). Rarely does the RH exceed 30%. It's usually around 15% or less. I have had to sticker and let dry some 8/4 cherry that I resawed to 4/4. Had my handy moisture meter out, and even though I bought the stuff from a large lumber supplier in Santa Ana, the inside of the cherry was nowhere near 12% More like 20%. Stickering and letting it sit in the garage for a week worked perfectly. No warped, twisted, or cupped boards. No issues using it afterward, or in the final product.

A few years ago, the company sent me to the Midwest for a couple of years. The humidity had a profound effect on my wood (and some of the stuff I'd built) I'd not experienced in California. All the sudden, drawers on a tool cabinet I'd built with the cherry were locked in place after expanding with the humidity! Plane bodies started to rust. Yikes! Gave me an appreciation for needing to pay attention more to wood movement with the humidity.

The most frequent challenge I have here is turning bowl blanks from wood that's been sealed with wax. Doesn't seem to matter how small the bowl blank is, or how long it's been acclimating in my garage, I nearly always need to account for the wood drying out and moving.

[jteneyck]

Have you ever read Bruce Hoadley's book "Understanding Wood"? Best $30 you can spend if you work wood.

John