02/06/2026
One of the most common sign shop callbacks? Rust stains from the wrong fasteners.
Here's a quick screw cheat sheet that'll save you rework:
🔩 ACM panels (Dibond/Alucobond): Self-tapping stainless steel, M4 x 12mm. Stainless is non-negotiable outdoors — zinc-plated rusts in 6 months.
🔩 Screw length rule: Letter depth + panel thickness + 5mm. 30mm letter + 3mm ACM = 38mm screw.
🔩 Acrylic letters: Threaded brass inserts into the acrylic back, then machine screws. Never self-tappers in raw acrylic.
🔩 Nylon washers between screw head and aluminum return. Skip them = white corrosion powder in under a year.
🔩 Ceiling-suspended signs: Threaded rod + lock nuts for the load. Screws are for positioning, not weight-bearing.
And the #1 mistake we see shops make? Drywall screws outdoors. They fail every time.
We stock the right fasteners for sign shops. DM us for specs or bulk pricing. www.8shopsigns.com
