If you have a wood window frame that needs repainting, the following tips can make your job easier and help you to achieve the results you desire.
Removing Flaked Paint
If the paint on your window frame has begun to chip or flake, you will want to remove these flakes or chips with a scraper, then completely sand the frame to achieve a smooth surface.
Using a Filler
If there are holes or deep scratches in the frame, it should be filled with wood putty or filler. Then the entire frame should be sanded until it is smooth. After filling the cracks, any dust or debris should be removed with a damp cloth so that the frame will be free of debris before you begin painting it.
Using a Primer
In using a darker paint color, or if the frame has been stripped down to bare wood, you will want to use a primer before painting.
It may be tempting for you to apply only a single coat of paint over the primer, but to have a durable finish; you will want to apply two or more coats. The last coat should be a latex or satin based paint. This will give you a stronger, more resilient finish.