How to Stain Anderson Windows

Raise the lower window sash about thee inches within the frame from the sill. Push the small, plastic L-shaped wash assist in both sides of the runner of the frame containing the sash firmly down through the runner to the top of the sash until they click into place. Tilt the top of the sash downwards toward you until the top clears the window frame and the window sash lies horizontally with the bottom still contained in the frame.

Use a flat-headed screwdriver and press the small steel shoe retainer clip release in one side of the frame slightly above the sash further into the frame away from the sash. Pull that side of the sash upwards so that the sash is diagonally set in the frame. Press the clip in the other side of the frame and increase the angle of the sash until it clears the frame. Pull the cleared sash free.

Move the wash assists to the top of the window. Pull the upper sash down within the window frame until it’s about five inches from the bottom window sill. Press the right side window jamb liner towards the window frame and pull the top of the sash towards you until the right side of the sash clears the liner. Press the left jamb into the frame and do the same with the left side of the window. Tilt it downwards until it lies horizontally with the bottom of the sash still contained within the frame. Remove the bottom of the sash using the same procedure used for the lower sash.

Place the window sashes onto a flat surface and then use a Phillips-head screwdriver to remove the hardware from the pieces, including the locks and window handles. Smooth the surfaces of the sash by sanding the wood with 120-grit sandpaper. Pull the rubber gasket that helps to protect the window frame from water damage from the groove in the upper sash. Wipe away the sanding residue from the sash with a rag.

Place masking tape along the edges of the windowpane to keep from applying stain to the glass.

Spray the wood stain onto the sash with an HVLP paint sprayer. Use enough to provide solid coverage without pooling onto the wood. Allow the stain to dry for the manufacturer’s recommended time. Apply a second layer of stain if you want a deeper color on the wood.

Remove any stain you may have inadvertently sprayed onto the glass by wiping it away with a paper towel containing solvent. Make sure to keep a fresh section of the towel on the glass at all times to avoid smearing the stain in a thin layer across the window’s surface.

Spray a layer of urethane onto the window to protect the stain from fading or from damage due to contact against the wood. Use an even coating of urethane, and allow it to dry according to the manufacturer's suggestion. Sand the wood grain raised in the sash from the moisture of the stain down with 220-grit sandpaper. Wipe away the residue, and then apply a second coat of the urethane and allow it to dry as well.

Remove the masking tape and then remove any urethane that seeped into the joint between the glass pane and the sash using a razor knife. Use the blade of the knife to scrape away any urethane that you sprayed onto the glass as well. Replace the window hardware on the sashes.

Repeat the staining process for the window jamb and molding surrounding the window frame. Allow it to dry completely before reinstalling the window sashes by reversing the process used to remove them from the frame.