Interlux Brightsides Marine Top Paint

I am a DIY roll-on paint job on my 95 with probe Marine Interlux Brightside urethane High. If you are not familiar with this kind of thing, then save the negative comments;). The white paint is more dull and flat and may oxidant? There is no peeling. When I run my finger in the car or wash it, there is the white powder all over my hand. Any input on what this powder is it? Anyway, I want a new coat. My car has no body damage at all other than nicks and scratches on the bumper of some rocks. Regarding the preparation work, sanding a car before the paint you should wet sand or dry? Also, do you buff / Polish or after you wash sand for a smooth surface, or do you want painted surface rough so that the new layer adheres? What grain for sanding before painting? 600-1000? Thank you for your help!

Hello to you ..
First departure at the car wash.
2nd. Tape around the car windows and door handles. This will prevent you from sanding the chrome and rubber parts.
3rd. sand the car with sandpaper. Grain 400. anything above 400 will be fined for painting stick.chips must be sanded. can be painted on a primer.
4th.make you clean the surface. a clean cloth with a solvent is the best.
5e. paint in the shade of a garage or carport. and does not start if there is wind

6th take your time! Do not rush!

I've never seen anyone do a "roll-on paint job" on a car using the exact picture of the car that followed seemed good .... I would suggest changing the method of painting and go with a spray paint standard automotive style. In this case, the vehicle must be free of any wax or grease prepared by wet sanding it with1000 seed and apply a sealer / primer and allow to dry (depending on the product label). Apply the base coat (color) - (I prefer the base coat / clear coat type), according to the label, then apply the clear coat.
The powder on the hands is the pigment of the paint color to come as you are out of the wash. I recommend the basecoat / clearcoat process. The light color seal.
This is not much of a DIY type project, but according to your abilities you can do OK.