How to Stain the Exterior of a Therma-Tru Fiberglass Door
- 1). Clean the door with a rag soaked in mineral spirits to remove surface dirt and very fine surface scratches and scuffs.
- 2). Mask door glass, hardware and hinges with blue painter's tape. Either mask the weatherstripping, or remove it. Push the weather-stripping back into place after the door is finished and dry.
- 3). Stir the stain thoroughly with a stir stick (provided in the Therma-Tru stain kit.) Mix all the pigment from the bottom of the can by scraping it up with the end of the stir stick and stirring until you have achieved a uniform consistency, without lumps.
- 4). Wipe some of the stain onto the provided sample piece of fiberglass if you are using the stain kit on a new door. Use one of the rags provided in the stain kit, and remove the excess with a clean rag. Wait a few minutes before wiping off the excess; apply a second coat if you want a darker effect.
- 5). Apply the stain using the sponge and rag applicators provided. Use the sponge to brush the stain into the edges and panel grooves and the rag for the flat areas. Work it into the grain with a circular motion, making sure all the grain and edges are saturated. Wait 10 to 15 minutes for the stain to dry. Wipe away the excess with the rag.
- 6). Brush the wiped stain in the direction of the grain with the natural bristle brush provided, which blends and softens the stain. Let the stain dry for at least 6 hours. Test for dryness by pressing a piece of masking tape to your sample. If the tape doesn't pull stain away when you remove it, you can proceed with the top coat. If any stain lifts with the tape, allow more drying time.
- 7). Stir (don't shake) the clear top coat.
- 8). Apply at least two thin, even coats of top coat, waiting 2 to 4 hours between coats. Use the 2-inch synthetic brush provided. The top coat will have a milky appearance at first but becomes clear as it dries.
Source...