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Forum topic by MaroonGoon posted 359 days ago 920 views 0 times favorited 19 replies Add to Favorites Watch
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MaroonGoon

280 posts in 543 days


359 days ago

Topic tags/keywords: oak wood movement uninsulated shop drying

Ok, so I have searched through a couple of different threads for a solid answer to this question but didn’t find an answer that would satisfy me. Here’s what is bouncing around my head:

As some of you may know through my recent threads, I have been drying a bunch of red oak that I plan to use in a couple of furniture projects for myself and my future wife in our future apartment (now that’s a lot of future ahead of me!). I am still very much a novice in woodworking and have not worked with wood that I have had to dry out myself. Everything I have done was with lumber that I bought already dry and so I didn’t have to worry too much about movement in the wood. Waiting for the oak to dry has given me plenty of time to think about what I must know before I actually begin working with the oak after it dries to a stable MC.

First off, I have an uninsulated shop and I live in deep East Texas where the average humidity is around 70%. I will most likely not get the MC of the wood any lower than 11% while it is in the covered conditions that it is in. I understand that I can bring the wood indoors to get the MC down to the level it needs to be and so the wood can stabilize in the conditions that it will be in the rest of its life (as a table, for example). But even if I did that and stabilized the wood, once I take it out of the house and leave it in my uninsulated workshop to build my table, wouldn’t the wood just regain moisture back to the equilibrium of the humid environment of my shop? This seems absurd, but the only way I figure I could prevent this from happening is to leave all my wood inside and only take some out at a time and then, once I’m done working with it for the day, bring it back inside…

How do some of you guys with uninsulated shops handle this situation, or am I over thinking this whole thing? Like I said, while waiting for this wood to dry, I don’t have much to do other than think so I wouldn’t be surprised if I’m just over analyzing it all.. I just want to make sure that I get everything sorted out before I actually begin building because I can’t afford to screw up a table and having to scrap everything that I have paid so much money for.

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso


19 replies so far

View Loren's profile

Loren

7156 posts in 2232 days


#1 posted 359 days ago

Design your stuff to allow for wood movement and you’ll probably
be alright. If you were shipping finished pieces to drier climates
you might have some reason for concern.

If you have the patience to do it, you might consider laying
out your parts on the rough boards, crosscutting and
bandsawing the rough parts, then bringing the parts in
the house for a few months. This way you’re not
bringing the whole lumber pile in the house.

I’m assuming you have rough lumber.

-- http://lawoodworking.com

View MaroonGoon's profile

MaroonGoon

280 posts in 543 days


#2 posted 359 days ago

Loren Thanks for the reply, you’re correct I am using rough lumber. I am sure designing for wood movement will solve a lot of my problems I will encounter. I have already begun doing some research on designing for wood movement and am looking for a book to purchase on that subject but I haven’t found one yet. Would you happen to recommend one?

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso

View Kelby's profile

Kelby

133 posts in 995 days


#3 posted 359 days ago

Buy a dehumidifier for your shop.

Designing to accommodate wood movement is always wise. However, as a novice woodworker, you are unlikely to do a perfect job of that on your first few pieces of furniture. Using a dehumidifier to keep the humidity at the same level as your home will give you a little more margin for error as you learn to design for movement.

-- Kelby

View Loren's profile

Loren

7156 posts in 2232 days


#4 posted 359 days ago

Well, something like Andy Rae’s book
“Taunton’s Complete Illustrated Guide to Furniture and Cabinet Construction”
would cover it adequately. It’s really not that
complicated but doing captured panels
(like frame and panel doors) deals with
the tightest tolerances in furniture.

-- http://lawoodworking.com

View davidroberts's profile

davidroberts

1001 posts in 2070 days


#5 posted 359 days ago

On a recent outdoor set of planter boxes, I kinda skipped the part about wood movement figuring if it pulls apart, well, it’s outdoors, it’s rustic, it’s rotted at the edges and somewhat warped from the get go, so how bad could it really be.

Yep, it’s that bad. It’s worse than bad. It’s bad, bad, bad.

I walked away from that little episode with a confirmed belief that while small cracks here and there may add character to a piece, I get annoyed, and bigger cracks you can stick your finger through, well that just ain’t right. Keep radial and tangential swirling in your head, and you’ll be alright.

-- God is Great, Wood is Good. nuff said.

View pintodeluxe's profile

pintodeluxe

3212 posts in 1398 days


#6 posted 359 days ago

I can’t speak to the uninsulated part, but kiln dried lumber that has been in my unheated shop for over a year is still at 6-8% m.c.
In the Pacific NW, an open barn = 15% equilibrium, air conditioned house 6-8% , and an uninsulted shop is probably somewhere in between.
this discusses basic drying techniques …http://lumberjocks.com/pintodeluxe/blog/36876

Just dry the lumber air dry for 1 year per inch of thickness stacked and stickered outside.
Then move it inside with a dehumidifier, fans, and a heat source if needed. 100 degree temps + airflow + low humidity will dry lumber in a week or two.
Once kiln dried, you will be surprised how dry it stays.

If you are still worried, build a coffin kiln with a lightbulb inside. This will always keep some project wood dry for you.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View MaroonGoon's profile

MaroonGoon

280 posts in 543 days


#7 posted 359 days ago

Kelby I considered buying a dehumidifier for my shop but was unsure about whether it would have a hard time maintaining a low humidity level with it being in an uninsulated space. What is your experience? Would it be more effective if I added batt insulation to my 12’x20’ shop?

Loren Thanks for the recommendation, I’ll check it out.

pinto That is good to know about the wood. I did notice your blog yesterday, you’re doing a good job with that bed. When you are talking about letting the wood dry outside then moving it inside, would it be safe to say that when the wood reaches its moisture equilibrium level outside then it is time to take it inside? I know some guys say that the year per inch rule is exaggerated but I have never dried wood before so I have no credible experience to base it off of.

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso

View Bampei's profile

Bampei

40 posts in 1928 days


#8 posted 359 days ago

+1 on the dehumidifier, but you need to make sure the drain is not to a bucket. Most modern Dehumidifiers have an auto shutoff when the resevoir is full. By draining either to the outside, or to a washtub if you have one in your shop solves the issue.

Best to buy one that can be set for a specific relative humidity. It will only come on when the humidity level exceeds the setting, and shut off when the targeted RH is reached. Ideally, you would set the target for the level of humidity that will be present in the location it will reside after being built.

All that being said, the wood will still move irrespective of moisture content….. just not much.

Don’t worry about the insulation. If you purchase a high quality dehumidifier, it should keep up regardless.

-- I dream of a better world, one where chickens can cross roads without having their motives questioned.

View MaroonGoon's profile

MaroonGoon

280 posts in 543 days


#9 posted 359 days ago

This thread has helped me a lot on figuring out my next steps, thanks for the replies guys.

This may seem like an obvious question, so even if my shop is 90 degrees, 45% RH and inside the house is 74 degrees, 45% RH then the wood MC will be the same and will be stable?

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso

View Tennessee's profile

Tennessee

1447 posts in 1099 days


#10 posted 359 days ago

As a small point of reference, I just recently cut up a maple log with my chain saw on the bias, to gain endgrain ovals for clock faces. The wood off the log was at about 34%. Bandsawed them to about 3/4” thick. Stickered them for about three weeks in my shop, that got it down to about 24-26%. A couple shrink cracked. SE Tennessee, climate very close to East Texas. Hot and humid. When I went to use them, chose two that had not cracked, took them inside the house until they hit <15%. Made one clock a few weeks ago, so far it is perfect. Coated the endgrain face and back with Tru-Oil. I did use screw construction, not glue, just in case of a little movement. All the other parts, supports and base were kiln or multi-year air dried. It is a pretty basic project, but still subject to possible cracks. So far, good to go. The face was spalted maple. The second one is still in the house, ready to go, no cracks, no movement. Now about two months old.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View MaroonGoon's profile

MaroonGoon

280 posts in 543 days


#11 posted 359 days ago

Bampei What size of dehumidifier would you recommend for my shop? It is approximately 240 sf floor area and about 1800 cubic feet volume.

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso

View Doss's profile

Doss

779 posts in 849 days


#12 posted 359 days ago

Well, I’m in the same kind of climate (central to south Mississippi where you don’t really walk places, you go for a light swim). I don’t think most of the people in other regions truly appreciate how wet our air is. You are most likely not going to hit 11% on any wood that’s drying outside. I dry slabs and 1x and 2x lumber of all sizes and a lot of it is red oak. In our climate, it takes a long time to dry through the summer months (which is about 80% of the year). Most of my wood levels off around 15-20% when air dried. I bring it inside for a while and can get it down to about 9% (with the AC running).

Also, 45% RH at 90° and 74° is completely different. It’s relative humidity. Without getting into calculation specifics, realize that:
75°F AND 45% RH = 0.00858 lbs of water per lb of air
90°F AND 45% RH = 0.014014 lbs of water per lb of air
So, the difference is there is roughly 1/2 the amount of water in the air @ 75° given the same relative humidity.

I’ve been building a “French farm-style cabriole leg table in white oak” (for whatever that means) in exactly the same conditions you are describing while I wait for my shop to be constructed. I say wait, but I have to do the constructing… so you know how that goes. Anyways, I’ll throw my advice in. You never said what types of furniture you’ll actually build, so this is just general advice.

Understanding your process, like Loren said, is important. Get as many of the steps you have to get done in the shop done up front. You can then move any steps like assembly, finish fitting, etc. inside a conditioned space. If the pieces you make are destined to be indoor pieces, you’ll want to the wood and whatever steps you can inside a conditioned space. Make sure you bring the wood in at least a month, preferably 2 months, before you start working on it. This is, of course, providing that the wood is already sufficiently air dried (20% or lower).

A dehumidifier is nice as some have already mentioned. You just need to make sure your shop is well-sealed.

If you’re building pieces with really tight tolerances, you’re probably going to have to wait until you have an appropriate place to build. That’s just how it is. I’d be really careful of the fasteners, the tightness of your joints, and the type and cut of the wood.

-- "Well, at least we can still use it as firewood... maybe." - Doss

View MaroonGoon's profile

MaroonGoon

280 posts in 543 days


#13 posted 359 days ago

Great info, Doss. I’m wanting to build a couple of end tables out of my wood so I’m mainly concerned about the joinery and the table top lamination moving between the shop conditions and indoor conditions. I think my next steps are buying the book Loren recommended and finding a good dehumidifier. Thanks for all the info, guys. It definitely helped.

-- "Only put off until tomorrow what you are willing to die having left undone." -- Pablo Picasso

View pintodeluxe's profile

pintodeluxe

3212 posts in 1398 days


#14 posted 359 days ago

In response to your question, yes when the wood reaches outdoor equilibrium m.c. for your area you can bring it indoors.
For some wood species it takes less than a year. I use white and red oak mostly, and I do believe it truly takes a year. If you lived in Arizona or a desert climate, that timetable may be a little different.

I usually run a dehumidifier in a confined space to dry wood. I am sure a dehumidifier running in a large shop space would help prevent tools from rusting, but I don’t know how efficiently it would dry lumber.

Best of luck

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View firefighterontheside's profile (online now)

firefighterontheside

3054 posts in 441 days


#15 posted 359 days ago

That was good info about RH. It is something that a lot of people aren’t sure about. You have to remember that it is “Relative” to the temperature.

-- Bill M. I love my job as a firefighter, but nothing gives me the satisfaction of running my hand over a project that I have built and just finished sanding.

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