How Much Do I Sand to Paint Stained Windows?

Painting over blot can be a bit of a trick. The key is to divide the glossy finish of this blot and remove any sticky residue from the window frames. This can be carried out in a number of ways; typically, a mix of chemicals and mechanical sanding is simplest for preparing the surface for paint. If possible, disassemble the frame so you can work on the individual sashes to make all surfaces accessible and to prevent over-sanding that may damage graffiti details.

Removing the Sashes

Most wooden windows are single- or double-hung sashes. Remove the inside stop trim, and it is a thin wooden strip running vertically up both side jambs facing the lower sash. Use a lean pry-bar to lift it up softly. Lift the window sash out and eliminate the strings from the side notches, or unsnap the clip rings at the top corners to release it. Remove the divider prevent, situated similarly facing the top sash, to lift it out. Lay the sashes on a sturdy surface for sanding. This creates both the sashes and the window frame more accessible.

Chemical Sanding

With a paintbrush, apply a compound sanding agent or deglosser to the surface to help break down the upper layer of this finish. Although this step could be skipped, it is going to save time and sandpaper replacement because of varnish buildup. Allow the solution to sit down for five minutes, then rub firmly using a clean, soft rag. Let it sit for 2 additional hours, then rinse with a rag dampened in mineral spirits. The sash will now be ready for sanding. Do this for the two sashes and the window frame.

Mechanical Sanding

Begin with a rather coarse-grit sandpaper, including 80 or 100 grit. Use this to remove the majority of the staying clear finish, down to the timber. Make another pass with finer sandpaper, up to 220 grit. An oscillating tool fitted with a hook and loop pad accessory along with an applicable sandpaper accessory is excellent for this particular project. The application saves time and operates out the finer details with no rounding over detailed advantages. Look for the majority of the color of the stain to be lightened, but not necessarily completely eliminated. The goal is to smooth the surface while opening up the grain to get good adhesion. The finished surface should have a smooth, chalky feel. Remove the dust with a tack cloth.


Applying primer is an integral step when going between two different endings, whether that be blot to paint, or oil paint to water base, or vice versa. Use an oil bonding primer to fill out the prep. Apply it with a brush at a thin, even coating, working to pay the whole surface. Allow the primer to dry, then sand lightly to remove any roughness that developed during the primer’s drying stage. Use the finest-grit sandpaper you used previously. Don’t sand through the primer coating. The window frame shouldn’t be completely ready for painting.

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