Spanish Cedar Movement

[Greg Caputo]

Looking for some real world experience regarding shrinkage of spanish cedar. I'm building a cabinet sized cigar humidor. Interior dimensions are: about 25" tall x 19" wide x 18" deep. Planning to line the inside with spanish cedar milled to 1/2" thick. The spanish cedar is currently at 8% moisture. When completed, I'm putting a huidifier inside that's supposed to keep the interior at 70% humidity. Current relative humidity in the shop is about 25%. I'm trying to figure out how much movement I should expect. Based on my research, looks like it'll be more than 1/4 inch. Does that seem correct? Any advice on spanish cedar is appreciated. Thanks.
Greg.

[Loren Woirhaye]

It's pretty stable... about like Mahogany I think. It might move 1/4" over 12" width but that's all I'd expect.

[Howard Acheson]

I'm a little confused. If the ceder will be inside a space that will have a constant relative humidity, there will be no movement of the cedar. Wood only moves when its Equilibrium Moisture Content (EMC) changes. If there is no change in EMC, there will be no movement.

[Peter Quinn]

I'm a little confused. If the ceder will be inside a space that will have a constant relative humidity, there will be no movement of the cedar. Wood only moves when its Equilibrium Moisture Content (EMC) changes. If there is no change in EMC, there will be no movement.

His cedar will be going from a shop space at 25% RH to a space at 70% RH once he humidifies the interior of the humidor. That's a pretty significant change in RH. The wood will line a closed box that will then be charged with humidity purposefully to keep cigars fresh. Come to think of it my old house is basically a humidor in the summer months.

[Brian Holcombe]

I would build it in a way in which the wood can move a little without catastrophic results. Over 25" you could have some significant movement as it goes from 25% to 70%. I would be tempted to make the panels in multiple individual pieces that have overlapping joints.

You could hide an overlapping joint with the supports for removable trays (which I assume your are making).

[Greg Caputo]

Kind of a ship-lap, right? And I like the notion of hiding the joints with the supports for the trays. I'm making those out of spanish cedar as well.

[Brian Holcombe]

Yup, should work nicely. I left my top and bottom liners free floating, just sort of trapped them in with the side panels and left them short enough that they would be able to expand but long enough that they would not be able to reveal the bottom.

[Bradley Gray]

I like spline and groove edges. Make 1/8 x 1/2" splines and groove the edges of the stock 1/4" deep.

[John Coloccia]

Wood movement is practically nothing longitudinally. You only need worry about radial and tangential expansion...the width and thickness of the board. So do your joinery endgrain to endgrain, leave a little extra space at the top of the box for the wood to get wider, and you can probsbly ignore the change in thickness.

[Sam Whit]

I wouldn't compensate for expansion too much. Humidors are built TIGHT. So tight that the maker I consider the best boasts that you can pick up the box with a piece of paper closed in the seal.

I think some type of flexible sealer in the joints might be all you need. Silicone perhaps?

Picture of the paper test on the main page. Tons of amazing humidors within.
http://www.waxingmoonhumidors.com/home

[Brian Holcombe]

Yes, you would want the humidor to seal tightly, that's done in part by having the liners slightly overlap the part between the top and bottom. It's not done by locking in the liners in a way where they will either split the box or prevent the box from closing when they expand as they come up to the right %.

i have a humidor I built by hand sitting behind me, it's currently holding 70% humidity and some fine habanos.