Sign Foam/Board

[ralph]

I am carving a sign for a church that will be 4'x6'. It will be carved on both sides
I am considering using high dencity urethane board . I am looking at 1.5" thick 18 lb density.
It will be suspended between a post on both ends.
I don't have any experience with this material, and was wondering if it will be strong enough to withstand our strong winds in Nebraska? It will be located in an open area . or will it need to be thicker ?

[Brady Watson]

Ralph,
You will need a frame to support the 6' span. I frequently mill two 1.06" dados/channels 1/2" deep in the center faces of this style sign. Then epoxy the 2 halves together to a 1" square AL tube frame. You could also use steel for the rails, just be sure to paint it well for the outdoors.

-Brady

[elcruisr]

Having experienced the winter winds in western Nebraska first hand (and I moved to Florida where the only big winds are hurricanes, right?). You might want to laminate the foam to a stronger core. We have done larger signs by using a plywood core as long as the edge is sealed. We have also glued together two layers of 1.5" 22lb foam on a large sign for wind resistance. Polyurethane foam works great, just watch the creep while it cures!

Eric

[ralph]

Thanks for the input.It Now apears to me the simpler way would be to sandwitch 3/4 plywood in the middle glueing foam filler stripps around the plywood so it is completly sealed.
I need to keep this sign as economicle as possable. So am wondering about the thickness and density of the foam. The carved out area will be .55" into the foam. So was wondering if .75"
foam would work since it will be glued to the plywood core for support.
I have no experince with this foam so any input about density would help.

Thanks Ralph

[billp]

Ralph,
Another option to consider is the use of one of the aluminum products such as "Aluminite" which you can find at places like Harbor sales (www.harborsales.net).
Advantages; very strong, very light, excellent for backing up foam and other mediums, and almost any "glop" ( I like silicone) will hold materials to it.
Disadvantage; About twice the price of plywood, but you might recoup that through the saving of time/materials in the edge sealing of the plywood.

[Brady Watson]

Got me thinking, Bill.

Why not Trupan or Extera? MUCH cheaper than sign foam and the Trupan mills nicely. As long as it is sealed properly, it should do the trick.

-Brady

[billp]

Oops, I spelled the name of the above product incorrectly. It should have read "Alumalite".

[kerrazy]

Ralph,
I would use 15lb Sign Foam or Precision Board 1" thich sandwiched with 3/4" MDO. I would also create a tenon with the MDO so it can be used to secure it to the posts. Again ensure you seal the edges of the MDO. I would also depending of the design have some one create a metal frame to cap the piece. It finishes off a sign of this size real nice. You could cut a template out of MDF for you metal manufacturer so he has the right bends and curves ofthe overall piece.
I would hesitate on extira as I have just recently had some primer and paint peel with it and have to experiment with it. give me a call if you want some more info. 613.880.8292
Dale