Do I need 2 coats of primer? Depending on how strong or bold the previous color is, it may be necessary to apply more than one coat of primer. However, it is not necessary to over apply the primer with so many coats. As long as the primer applies uniformly over the previous color, then one or two coats should be sufficient.
Is three coats of primer too much? You will want to use 2-3 coats of primer to ensure there is a good bond between the new paint and the wall, and also to cover up any previous colors, especially if they are red, orange, or a strange outdated color. In short, you will typically need 2 coats of primer for most painting projects.
Should I sand between coats of primer on furniture? Let that coat dry before doing one or two more. The goal is to have the piece completely covered in a thin, even coat of primer. Depending on the wood type, I sometimes sand before the last coat of primer goes on, as the primer can raise the grain of the wood.
How thick should primer coat be? For a normally clean environment, a coat of up to 50 microns is considered adequate. For a dusty or humid location requiring constant servicing and cleaning, a thicker coat, say, up to 70–80 microns, is considered to be adequate. A thickness of up to 50 microns is possible through one coat of primer and paint.