Excerpt from Simpson Doors
  • Doors should be conditioned to average prevailing relative humidity of the locality before hanging.
  • Doors should not be subject to extreme or rapid changes in heat or humidity. Avoid sudden changes such as forced heat to dry out a building.
  • Hang door before finishing, and then remove to finish properly.
  • All surfaces of the door must be properly finished. The edges (top, bottom and sides) should be coated with each and every coat of finish that is applied to the exterior surface of the door. Doors must be dry before finishing.
  • For doors with glass, it is common to receive putty "squeeze out" around the edges of the glass.
  • This extra putty (squeeze out) helps prevent seal failure. If you have received a door with putty "squeeze out" around the glass, it can be removed using a plastic knife. DO NOT use razor blades or sharp objects to remove the excess putty. These items will scratch the glass.
NOTE: It is the finisher's responsibility to protect glass prior to and during finishing. On doors that have plastic film protection on glass, removal of plastic film protection is required immediately after applying the finish. Failure to remove the plastic film at this time may cause harm to the glass and will create difficulty in removing the film at a later time. Do not use razor blades or sharp objects to remove the film or clean the glass. These items will scratch the glass
Exterior Finishing
1. Stain-and-Clear Finish
The first coat should be a stain-and-sealer, a combination of stain and sealer, which colors the door and seals the surface. It is available in a wide range of colors. The stain-and-sealer should have an alkyd-resin base. Under no circumstances should a lacquer-based toner or any other lacquer-based finish be used on exterior doors.
The second and third coats (two top coats minimum) may be a solvent-borne (oil-base, alkyd-resin base, polyurethane resin-base) or a water-borne (latex resin-base) clear finish. See notes (1) and (2) below.
Interior Finishing
1. Stain-and-Clear Finish
A solvent-borne finish system is recommended for interior doors and may be a lacquer-based system. If a brush application is to be used, it is recommended that a pre-sealer be used prior to staining. For best performance, a minimum of two clear top coats should be used over stains.

2. Paint Finish
Doors should be sealed with a good quality oil-base primer followed by two top coats of a solvent-base or latex enamel.