Interior Sign Wood Movement Concern

[Rik Rickerson]

Greetings,

I will be building an interior sign for a client. It's dimensions are 6' wide 45" tall and 2" thick. It will consist of three laminations: bottom & middle - 7/8" walnut, top 1/4" cherry. The logo and text will be routed 1" deep. It will have a floating 2" walnut border. The finish will be oil and wax.

I'm very concerned with wood movement so my question is which option would be better?

Option 1: Should I laminate all the layers with the grain going in the same direction? I don't know if walnut and cherry move at the same rate so I'm concerned that the thicker walnut layer will over power the thinner cherry layer resulting in cracks in the cherry.

Option 2: Laminating the middle layer with the grain running perpendicular to the top and bottom layer creating a plywood effect. One advantage this option offers is the vertical grain would allow the routed text to be more visually appealing.

Take care,
Rik

[Carl Eyman]

Rik: I have the information on the relative movements of cherry & walnut at my shop. Want me to send it tomorrow? Being indoors, once the woods are stable to the envirement will there be much movement?

[Jamie Buxton]

If you look at tables of wood movement rate, you see that for any one species, the difference between radial expansion and tangential expansion is considerably larger than the differences in tangential expansion among most North American hardwoods. If you want to be really picky, you can laminate quartersawn boards to quartersawn boards, and plain-sawn to plain-sawn. (Me, I only get quartersawn if I pay extra, so I don't see it much.) If you laminate plain-sawn to plain-sawn, the composite will move pretty much like a solid plain-sawn board of either species.

Me, I wouldn't attempt your quasi-plywood version of this sign. You'll have three thick plys and a long (45") cross-grain glue joint. Even indoors, this might well come apart.

[Rik Rickerson]

Carl: I'd appreciate it if you'd email that info. You're correct in that the indoor environment will not see much change. Both the temperature and humidity are regulated.

[Chris Padilla]

Rik,

Your key would be to make sure the wood is stable to the environment they expect to spend most of their time in. Can you build it at the client's place? Or, at least get the wood all ready and then put in the client's place for a week or two?? Crazy...but it might work....

[Scott Banbury]

I've done some routed signs where a contrasting wood was exposed by routing through the top layer--Walnut exposed through ERC. The way I did it was to tongue and groove both panels, register them at the bottom and then float them in a frame.

They've worked well.