We do a lot of this type of sign work. We commonly use 12mm PVC or half inch acrylic face-laminated with Brushed Silver Chemetal or a similar laminate. Use contact cement, water or solvent based for laminating.
Use a sharp fine-tooth carbide blade for cutting the panel or use the router table. Matthews "Brushed Aluminum" paint for the edges is an excellent match to Silver Chemetal.
We then flush mount PVC flat cutout letters that have been painted. Letter thicknesses range from 6mm, 12mm or thicker. For letter thicknesses greater than 1 inch, we stack the PVC.
Acrylic works fine, too, for both panel and FCO graphics, as do other substrates. There is no wrong material, in my opinion. We have experimented a lot. Even Gatorfoam brand foam board will work, too, but it is not as problem free. Edges must be carefully sealed before painting with a paint like Matthews. Also, while Gatorfoam has a good reputation for staying flat, it can curl if laminated on one side only. And, of course, a foam board is more tender, susceptible to damage. PVC seems to be an ideal substrate for interior signs like this.
PAINTING TIPS FOR PVC LETTERS
Sand the sheet before cutting out the letters. 400 grit on a DA does a thorough job with little effort. This is if you are not face-laminating, of course, but only painting the cut out lettters.
Paint the back sides of the letters first. This has two advantages. The painted backs yield a good surface for double-sided tape. But more importantly, especially on small letters, the edges get better coverage. It is often difficult to get good edge coverage on a small PVC letter, particularly in the closed counters, when only spraying from the front. The additional paint on the edges also helps cover tool marks from the router bit better.
After you have painted the backs of the letters, apply your mounting tape before turning them over to paint the fronts. This raises the letters slightly, preventing a paint build up at the base of the letters where it contacts whatever piece of material you use to hold the letters while painting (we use scrap Polymetal). When the letters are dry they do not even need to be removed from the backer. They can be conveniently transported to the installation site still attached. Also, if you mount the letters to the backer in the correct order before you paint, it is easy to spot something missing, such as a comma or dot, while loading the truck—not as easy to do if the letters are all dumped into a cardboard box. Installers even find that when they pull off the letters from the carrier piece at the job site, the tape liner often stays on the back piece, eliminating the need for picking off every piece of liner.
Brad in Kansas City
