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Material Suggestions for Wall Mount Sign


New Member
We were contacted by a customer to replace a wall mounted (stone wall) sign here in Northern VA. The current sign looks to be 1/2" HDU painted and screwed (doesn't appear to be glued) to OSB. There are 1/4" thick letters attached to the sign and some vinyl items on it. Everything is faded so I assume it has been up at least 10 years. The OSB looks relatively new. Someone may have fixed it, but I am unsure.

They want "the same sign". I can get HDU and paint it, as much as I don't want to. My issue is the letters. They are not acrylic as I can push into them slightly with my fingernail. I believe they are PVC but I am unsure. I cannot damage the sign to verify before quoting.

My original plan was to use 3/4" PVC, painted, with 1/2" PVC letters. Then I got on the forum and read...and read...and read. Looks like even painted PVC is not recommended for use in this area, mounted to a wall because of expansion and contraction. I did make 1" thick PVC signs, painted with auto paint and mounted to 4x4's a few years ago, they look great. Unsure if I got lucky though.

I am considering 6MM or 10MM ACM with 3MM ish Letters, painted. I am waiting for the paint to dry on what I have in the shop as I am testing. Currently, I do not like the way the edge looks but that is why I am here. These would be painted and somehow attached. Still unsure of all the options for this.

If I use ACM as the base, do I need to worry about the exp/contract of Acrylic on the ACM? Could I mechanically mount without issue? Alot of folks recommend VHT/VHB tape but I am unsure of the longevity for this project.

I asked the customer if we could make it single layer, painted - which negates my issue. I am here because I assume the customer will reply that they "want the same". I am trying to plan ahead. Any help would be appreciated.


New Member
Others will chime in, I'm sure. I'd vote not using ACM for dimensional letters outside. Too thin to attach to the backer with a fastener and I've heard that cut ACM can delaminate in time. Plus the edge appeal isn't nice. I don't think 10mm ACM exists. HDU is expensive and mostly used for carved signs. There's a recent thread going about HDU letters: https://www.signs101.com/threads/dimensional-sign-with-hdu.171434/

Depends on how thick of a backer they want, but I'd use a sheet of painted ACM or aluminum with acrylic letters screwed on (post mount). Many options here. Can you post an image of the existing sign?