Stencils provide crisp sign lettering.
Plexiglass is a lightweight yet highly durable material that stands up well to the elements. For this reason, it is commonly used to make outdoor signs. Unfortunately, new paint does not adhere well to plexiglass' slick, nonporous surface without some prep-work. If you want to paint over a plexiglass sign, you'll need to prime its surface properly and use stencils to achieve crisp sign lettering.
Instructions
1. Clean a used plexiglass sign with dish soap and water. Brand new plexiglass signs are presumably clean, and you won't need to wash them unless they show obvious signs of grime.
2. Coat the entire sign in bonding primer with a medium-nap roller. Bonding primer is formulated to stick to even very sleek surfaces, such as plexiglass, vinyl and ceramic. This special primer costs a few dollars more per gallon but provides the best base coat for a plexiglass surface. Wait for the primer to "cure" before continuing. Bonding primer takes longer to cure than general purpose primers, so refer to the manufacturer's instructions for how long you must let the primer dry.
3. Paint the sign's background color using an oil-base exterior spray paint. Wait for the spray paint to dry before continuing.
4. Apply stencils to the surface using painter's masking tape. Cover other exposed areas with painter's masking tape or plastic sheeting. If you're a skilled painter, you can trace your sign lettering or pictures using a pencil for freehand painting.
5. Spray oil-base exterior paint over the stenciled lettering for your sign. For a freehand design, apply oil-base paint over your pencil marks using oil-base paint and a synthetic-bristled brush. Wait for the paint to dry.
6. Remove the stencils and painter's masking tape when the paint is fully dry. Erase any stray pencil marks, if you painted freehand.
