Staining Wood Grain Fiberglass Doors | How to Guide | Plastpro | Plastpro Inc

Stain-KIT materials included:

  1. 1ZAR® Exterior Water Based Poly High Performance (Qt)
  2. 2ZAR® Stain (Qt)
  3. 3Mineral Spirits (4 Oz.)
  4. 4Cheese Cloths
  5. 5Two 2” foam brushes
  6. 6One 2½” synthetic bristle brush
  7. 7Two stir sticks
  8. 8One pair of latex gloves
  9. 9Door staining instructions
  10. 10Two Skin Samples

Contains everything you need to stain one pre-hung door and two sidelites or one double door unit.

Staining Wood Grain Fiberglass Doors

Step 1: Surface Preparation (Do not sand grained fiberglass!)

  1. Lay door horizontally on saw horses or a table.

  2. Remove all hardware and mask off anything you don’t want stained, such as the glass insert.

  3. Wipe the door with mineral spirits to clean any dust or residue from the surface. Allow the door surface to dry completely before applying stain.

*For best stain results, please make sure temperatures are between 50°F - 90°F, humidity below 85%, do not stain in direct sunlight, and do not stain or apply top coat when dew is present.

Step 2: Apply the Stain to the Door

Stain color options

You can control the shade (lighter or darker) of each of the 7 stain colors during application by varying the amount of stain applied.

First coat

  1. Starting at the center of the door, stain one to two panels at a time. Apply stain with a 2½” soft bristle brush, or a rag. Apply enough stain to fill the door grain. (Refer to the door staining diagram.)

  2. With a clean, lint-free, 24” x 24” cloth, softly wipe the surface until you reach your desired tone.

    TIP: When the rag becomes saturated with stain, re-fold to work with a less saturated section. Be sure to use the same rag for the whole door.

  3. After all the stain is brushed evenly, you may add finishing touches by using a small 1” to 2” brush or cotton swabs.

Second Coat (if desired)

Let the stain dry thoroughly per the stain manufacturer’s recommendation before applying the second coat of stain. Temperature and conditions will affect dry time.

Step 3: Protective Top Coat

Apply a polyurethane top coat with UV inhibitors like ZAR™ Exterior Polyurethane, Wood Kote® Flagship UV, or Minwax® Fast Drying Polyurethane for exterior applications.

  1. After the stain has completely dried (per stain manufacturer’s directions), mix the top coat well and apply evenly, using a clean, dry, 2” soft bristle brush or a 2” foam brush. Be sure to stop when the grain changes direction.

  2. Apply three coats of finish, allowing at least 3 hours of drying time beween each application.

Normal Maintenance

Even a well-finished fiberglass door will be affected by exposure and weathering from the sun, moisture, and air pollutants. It is considered normal maintenance to re-apply the topcoat approximately every two years.

Due to the variability in finishing materials, application conditions, and techniques, all of which are beyond the control of Plastpro, Plastpro cannot be responsible for the performance of field applied finishes or individual application techniques.

*Staining instructions are for Oil-Based, Premium Quality Wood Stains, or similar products designed for use on a fiberglass surface. Please note the instructions indicated are specific to the Zar brand stain included in our stain kit. Please reference the stain manufacturer’s instructions before applying any stain.