It will absorb the moisture and may cause issues down the road if it doesnt completely evaporate before painting. Before moving on to paint check the primer instructions.
10 Car Paint Prep Tips
Do i need to sand primer before painting car. While polyester primers are great for filling they can be porous. Wipe the car down again with solvent and a clean rag careful not to use too much or it can wipe off the primer. Car restoration can be a. After some time with the 400 grit you can move to a 600 grit paper to give yourself a nice smooth surface to work with when you are painting the car. As a starting point if you are sanding a coat of rough primer you can start with a 400 grit sandpaper to knock down all of those little bumps. Never wet sand polyester primer.
Some coats of a good primer will make it even stronger. Dry sanding primer is sometimes better then wet sanding but well let you be the judge which is best. Once youre finished sanding the polyester primer use a urethane primer or a sealer over it. I like to wet sand for final painting so if youre sanding a 2k primer an epoxy or even a clear coated surface or maybe if you have a car with an already nice paint job on it say you have a red car with a nice paint job but youd like to put a different red hue on it or some kind of metallic maybeall you have to do really is scuff down the clear coat with 400 grit then you can lay your base coat and clear coat right on top of that. Wet sand the primer making sure to sand out any drips scratches or other rough spots with 800 1200 grit sand paper. In this video well learn the best way to sand primer for painting.
Any time you sand away from your vehicles paint and expose bare metal you should apply primer before you paint sanding lightly between coats to be sure youve got a smooth surface every time.