Acclimating advice

[dnkc]

I built a bed for my wife and I this past spring (10 months ago) out of regular old pine from Lowes. My shop is not climate controlled and I didn't acclimate the wood inside our home before building the bed. The wood hasn't moved much, the piece is rustic in style anyway, so the joints weren't perfect to begin with. Some friends liked our bed and asked me to build one for them, I did theirs in the summer and it still looks great now, just a slight movement in some of the boards. I made a few beds this fall with the same design. The headboard and frame are not connected and the headboard is attached to the wall.

I recently had someone ask me to make a bed from a different design where the frame and headboard are connected. My concern is that the wood movement will cause the bed to not work out as nicely for these people as the other design did for us. I know you are supposed to acclimate the wood in its final environment before working with it, but how do I do that with an entire bed? The only things I know to do are to make the shop climate controlled, which isn't an option right now. Or to bring all the wood into our house to acclimate. Although wouldn't it just revert back to the outdoor environment once I take it into the shop?

Am I worrying about this too much, or should I not try and sell someone a bed that may warp?

 

[JohnnyR]

First you need to acclimate all the wood together in your shop. I generally cut rough lumber a little oversize, skip plane it and let it sit for a week before milling it to correct size. From what I see the only movement that would concern me is the panel. From the picture it looks like you captured it in dadoes on all four sides. This will prevent any large warp. Just need to allow for wood movement up & down. When I've done this I've put a strip of foam weather stripping in the dadoes to help keep the panel centered. The bed rails are fastened mechanically so movement is not a problem. Good luck, nice looking bed.

 

[Woodmolds]

One must do thing is to inform the client that wood is a natural product and some seasonal wood movement is eminent.

 

[scsmith42]

Daniel, Lowes typically has two types of pine. Dimensional structural lumber, such as 2 x 4's, 2 x 8's, etc is kiln dried to around 18% MC.

They also stock 1X material for trim, shelf boards, etc, which is dried to a lower MC%. Ideally you want the lumber to dry below 10% MC.

Given your options if you simply place a dehumidifier in your shop (and keep the temp over 50 degrees), the lumber will acclimate in your shop. It's best to sticker it while it acclimates.

 

[Jeff]

Am I worrying about this too much, or should I not try and sell someone a bed that may warp?

Yes. You're overthinking the amount of wood movement whichever bed design or wood species that you use. Your "regular old pine" from Lowe's was kiln dried to about 16-18%. If you buy rough cut lumber it'll probably be kiln dried to about 7-9%. Build it in your unconditioned garage in the summer or winter and there will be some "acclimation" and when taken inside the house there will be some acclimation as well, but the piece isn't destined to warp, split, and blow apart. Furniture in a home with central ac and heat will average about 12-13% year round in NC.

http://www.finewoodworking.com/2013/08/29/calculating-for-wood-movement

Is your picture one of the beds that you built or is it a pic of one that you'd like to build for your new client?

 

[dnkc]

Thanks for all the advice.
-Tony, Thanks for the tip, I will let the client know about possible movement.
-Jeff, Thanks for setting my mind at ease and giving me the percentages. The picture I included in the original is the bed I built for myself. Here is a Sketchup of what i'm planning to build.

 

[Jeff]

Which pieces of your bed design do you expect to move because of the humidity/temperature fluctuations in your shop and after moving the bed indoors?

FYI, here's an equilibrium moisture content (EMC) chart for regions of NC (also see Table 1).

http://www.woodweb.com/knowledge_base_images/zp/equilibrium_moisture_content.pdf

	% EMC, 12 month avg.
Charlotte	12.7
Greensboro	12.9
Raleigh	13.1

So your regular old pine from Lowe's at 18% EMC will shrink a bit while moving towards 12-13% in your shop. You calculate how much for boards of a given width.

http://www.woodbin.com/calcs/shrinkulator/

 

[Rwe2156]

Construction lumber is often just downright wet, often running >20% MC. I would sticker and store the wood inside your house (yes, in the house) if possible. With the heat running this time of year, it will rapidly dry out. The biggest issue is with panels and wide tops. Shrinkage can be dramatic, on the order of 1/4" per foot. Hint: Be sure to finish the panel before installing so if it shrinks no unfinished wood will we exposed.

Generally speaking building projects in non-climate controlled shop can be a big, big problem and I struggled with it for years, until (read below). It depends somewhat on the type of wood and what you're starting with, moisture-wise. Even with kiln dried lumber, allowing the wood to sit in a the shop can result in a lot of disappointment, for example, the next morning when you see your nice flat panels cupped like potato chips.

I am fortunate to have a climate controlled studio in a corner of my shop where I acclimate wood and build my projects as well as store all my hand tools (no rust problems anymore). It is well worth the investment if possible, even if only a 12x12 room.

I recommend cutting and rough milling all your parts and keep stickered in your house. (Then explain to your better 1/2 why you need that studio ;-) In a few weeks the MC should be down enough for a final milling and assembly.

Helps to keep your parts sealed in a plastic bags between work.

Hope this helps.

 

[Gofor]

If you use the right joinery, and the wood is close to equal moisture content, you will be fine. If you use through bolts into cleats, etc for assembling the side rails to the ends, then elongated the top hole to allow for wood movement. As for the design, the main area of concern looks to be the "fill" panels in the headboard. If its slatted or tongue & groove, allow enough space between each board/slat to let the wood move. If the vertical boards are wide, only glue/screw/blind dowel the ends in the center if you make a hard attachment. Most of the items I have made were milled and put together with a MC between 12 and 16% And all have held up fine.

Whenever I buy wood from the borg, especially SYP or PT lumber, I try to stack and sticker it to some extent at least for a week before milling it. (PT lumber gets more if at all possible). If I plane off much, regardless of species, I give it at least overnight or more to acclimate some before doing any joinery work on it. That seems to be the operation that will result in the most warpage, as much from exposing any stress areas as moisture.

Lets face it: People were making ornate beds long before controlled climate spaces, and some have held up for centuries.

Go

 

[dnkc]

Thanks for all the helpful info and advice.

My main areas of concern are the connection between the rails and ends as well as the vertical "panel" pieces of the headboard. I was planning to join the rails with this hardware.... https://smile.amazon.com/gp/product/B001DSZGCU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1.
For the panel pieces, I'm using 1x4's that are 36" long. I was going to screw them into the horizontal pieces and either pocket screw or glue them together. I used this method on our bed except the pieces ran horizontal and they were almost 7' long. We've seen very little movement.
-Gofor, what do you mean by connecting the ends in the center?

 

[JohnnyR]

Thanks for all the helpful info and advice.

My main areas of concern are the connection between the rails and ends as well as the vertical "panel" pieces of the headboard. I was planning to join the rails with this hardware.... https://smile.amazon.com/gp/product/B001DSZGCU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1.
For the panel pieces, I'm using 1x4's that are 36" long. I was going to screw them into the horizontal pieces and either pocket screw or glue them together. I used this method on our bed except the pieces ran horizontal and they were almost 7' long. We've seen very little movement.
-Gofor, what do you mean by connecting the ends in the center?

As for Gofors good suggestion, after gluing the panel and inserting in the dadoes, just pin the center so that expansion occurs equally at both ends (sides) so you can minimize the depth of the dado to accommodate the movement.
I've used those brackets before and don't like them. I followed directions to a T and they did not draw the rails tight. After fiddling around with new screw placements I got it drawn tight but the tolerances were very tight. My first and last bed used these which you can get at Klingspor. http://www.leevalley.com/US/Hardware/page.aspx?p=67916&cat=3,40842,43730&ap=1

 

[Gofor]

I was/am assuming that you are going to dado the horizontal pieces, and insert tenon/tongues on the 1 x 4 slat into the dado. If you glue or multiple screw across the full width of the slat, you may run into a problem when the slat tries to contract or expand. By just putting a dab of glue on the center 1" - 1" 1/2" only (or one pocket screw) just the center is anchored so the slat can expand and contract without causing crack-inducing stress. This technique also works for large door panels, etc when you have a cross grain situation between the panel and the rails (typically used in frame and panel construction). It keeps the panel/slat from being loose and rattling, but still allows for seasonal dimensional changes.

With a 1 x 4, you may or may not have an issue with each individual slat, depending on the wood species and its co-efficient of expansion, but pine moves quite a bit. So, the other thing to consider is to not jam the slats against each other during assembly. Even with air conditioning, you never know when there could be a power outage associated with high humidity and high temp during a thunderstorm or hurricane. My 40" wide walnut kitchen table has changed 3/8" over the width, so the pine over a 7' length could very easily exceed double that. If the slats are jammed together to start with, that 3/4" expansion has to go somewhere, and will lead to bowing the slats or pushing the end posts apart,

If you don't want to be able to see through the slats during dry periods when the slats are at their minimum width, you can either make them tongue and groove, so the tongues prevent any open gaps, or you could back the slats with a thin plywood panel (hardboard or a tight weave heavy fabric are other options).

As for how much gap between slats, possibly someone here who uses that design can give you guidance. My guess is it wouldn't have to be more than the thickness of a business card, but I may be wrong. If you were building this in the summer with high humidity and no a/c in the shop, you would be at worst case scenario as far as max width, so no gap would most likely work. In the winter with low humidity, I would leave a bit of a gap.

With your previous bed design, you said you ran the slats horizontal. This put the cross grain problem at the posts, but also greatly reduced the cross grain width, What was successful there may not be so much so across a 7' span.

Hope this helps and doesn't confuse. I didn't have much luck finding illustrations for what I am saying.

Go

PS. Just center fastening would also work with a pocket screw and a simple butt joint as far as expansion, but you risk the slats cupping if you do that, which is why I don't recommend it. I am afraid that if you use two pocket screws, one in from each edge, the slat will split when the slat shrinks. The tongue/dado method stops the cupping. The center fastener stops the splitting. (On retrospect, I guess I should have just said this in the beginning. LOL)

 

[Jeff]

Good advice from everyone and +1 to Lee Valley hardware for the bed rails.

How about ship lapped 1 x 4s for your headboard panel. The individual boards are not glued together or screwed to anything so expansion/contraction movement is less problematic and the rabbeted edges overlap each other about 3/8". The top and bottom of the ship lap panel sits in your horizontal sections of the headboard frame but I didn't add them.

https://www.youtube.com/watch?v=Q6FxG3ll-lw

It's easy to model in SketchUp.

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