Sign foam - how to fix to backing board

[bcondon]

Local company wants to make a outside sign for a warehouse which will measure 5 feet high x 54 feet long.

I have not used sign foam in the past which is the basis of most of the quesions,

I plan on using plywood for the backing board (5x10' sheets) and then fix the foam letters (3 feet high) to the plywood. I will use nutm screw and washer to affix the plywood to the steel building.

I plan to prime and paint the letters front and back for protection


How would you suggest affixing the letters to the plywood? Liquid Nail type adhesive? mechanical such as wood screw (I would think the wind would tear up the foam with screws?)

Thanks for your suggestions

Bob

[Team One Display Services]

I would probably build it from another material - the plywood would make me nervous as it is going to expand and contract at different rates than the signfoam letters. Could you use a straight channel behind the letters instead of plywood sheets?

But to answer your questions -

Don't use liquid nails - it will become brittle and the letters will fall off.
You can screw into the sign foam, but over time the foam and the screws will seperate as the foam expands and contracts around the screw. To attach signfoam to a stud mount, you need to pre drill a hole into the HDU, fill with an epoxy or expanding glue, then insert the stud.

Also, you can epoxy a backer board to HDU for rigidity and to use as an anchor point. .080 to .125 Aluminum works very well for this - Extira can also be used as a backer but adds a lot of weight.

[bcondon]

Larry,

Thanks for the advice. I have used epoxy in boat building and that should hold it!

When you say straight channel, can you explain a little further. Are we talking steel or a aluminum uchannel, or a product like the steel studding which would be refinished?

I also have the option of securing the letters directly to the side of the building with through hole nuts and bolts. I could predrill large, fill with epoxy and then drill out finish size or put a piece of plastic straw in the center so drilling is not necessary.

Again, thanks for your help

Bob Condon