By signcraft
Posted on Monday, November 27th, 2023
Readers want to know: “What’s the most practical way to support a 4×8 sign made of 3mm aluminum composite sheet that is mounted on two 4×4 posts? Does it always need a frame or stringers?”
We’ve all seen ACM 4×8 panels that are mounted on two 4x4s and are buckling or warping. They look bad and customers don’t like them. How do you mount them to avoid this?
Find answers from readers below and add your own if you can help.
At 3mm ACM is not designed to be used as a structural support element like MDO plywood, it just doesn’t have the strength so yes, a frame or stringers is necessary to keep the material from buckling.
For 3mm ACM we’ve always used a few 2×4 stringers
I think the least expensive option is to use one 2x4x8 hung in the middle of the sign lengthwise and attached to the 4×4 posts is the minimum for this type of substrate, and/or you can move the posts closer together and shorten the cross piece. The material really needs support, I live in a high wind area and I really have no choice in my case, good luck!
We frame it with thin wall aluminum tubing and high tech adhesive. Makes a very flat durable sign panel.
If mounting on poles I will use a metal frame, my sign shop is in Far North Queensland Australia & we get some very hot weather here. If the sign is going to be copping the heat I will elongate the holes to allow for expansion, the same for if it is to be mounted onto a solid wall.
Don’t make the mistake of putting the posts at the extreme ends. Come in 18″ from each end for better results.