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I always thought that wet sanding between coats was more to smooth out slight imperfections in the previous coat than for purposes of improving adhesion. After all, when paint is sprayed on in many layers, nobody ever wet sands between coats, as far as I'm aware.





The wet sanding does two jobs at various points during the paint job... you have to break the paint job in to two different phases when talking about wet sanding :

BUILD UP PHASE WET SANDING - this wet sanding happens after every second or third coat of paint as you are building up your color coverage. It smooths out the surface to which the next layers of paint are going to be put on. It also removes some of the gloss off the previous coats so that the next addition of layers of paint have something to grip on to.

FINAL POLISHING AND SHINE WET SANDING - this wet sanding happens to your very last FINAL coat of paint. It is going for the maximum smoothness of the outer layer of the final coat of paint. Because you are using your highest grit of sand paper... you are actually polishing the surface.

Hopefully that explains the difference in purpose between the two different phases of wet sanding that happen during the rolling process.

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