A question on material you would use

[jhicks]

We are in the final stages of a new sign design and about to make our final material selection. We thought we might use Komacel but after some discussions we don't think this is such a good idea.We have used Medex and could here but its pretty heavy.
So here is the application. Sign face is 50 feet wide x 3 ft high on the South facing side and 15 ft x 3 ft on the east side of a corner approximately 18 feet above the sidewalk.
Color is to be matte black. The entire sign will have a simple profile 2" wide border trim we may run in Medex (but again open to suggestions and ideas) and 1,1/2" thick HDU letters about 24" high mounted with standoffs approx 2" off the sign face painted in a gold paint. We use 2 part polyurethane paint and feel Ok with that aspect but open to suggestions and alternatives.
The problem I hear about is warping PVC/Komacel, especially in black. My "OLD" friend Joe Crumley suggests Di-Bond and I think that's an excellent suggestion (Plus it is prefinished in Black) but wanted to put it out there to see what you other sign makers think on standoffs, material, and mounting idea you have used successfully.
The sign will most likely be hung with a french cleat and secured with screws to furing strips mounted to the brick building behind the border trim top and bottom (maybe in the middle as well).
All input and experience is appreciated. Even if it's a horror story or other advice we should be mindful of.
Thanks

[joe]

One more thought Jerry.

If possible I'd find some way to include air escape vents. Perhaps you could leave a small gap along the top and bottom edges and have the sign off the surface.

The amount of heat this unit will collect is going to be considerable.

[fleinbach]

Jerry,

I have only ever made signs for my own use and that's very few but when I did I used MDO Plywood. It's easy to work with and takes paint very well. It's also way cheaper then a lot of the materials I've seen mentioned on this forum. Of course I'm sure the price is worth it if your carving your letters into the material but it seems that's not your intention. Since it appears your looking for a backer to place the lettering onto this would work very well. Back in the 80's I used a lot of it to build satellite antennas. They held up increadably well I know of one I saw 15 years after it was constructed and it was still in great shape. MDO and HDO plywood is what they use to make the big green signs you see on the highways. I'm sure you will get some better responses from the Sign guys but that's my take on it.

[tuck]

I think Joe has the best idea with the Di-Bond for your substrate. It's finished in matte black, so no painting required, and it's just about bullet proof. It's only 3mm thick, so I don't know if that will present a problem, but if properly mounted, it will never warp and the paint is baked-on enamel from the factory. Can't beat that!

[jhicks]

Thanks guys, looking like the Di-Bond is in the lead at the moment but still open to suggestions if anyone has more.
Yes Joe, Agreed.. some ventilation is desireable and achieveable since it will be "off the wall" so thanks again. The devil's in the details.