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Just to make sure -- when prepping the car before the first coat how far down do I need to go?

Sand it all down to where it is whiteish in the picture?

I had a rust spot (top-left) that sanded down to bare metal when I started sanding it. Will this be fine?





The most important thing about the initial sanding down process is to make sure that you end up with one smooth level surface. Meaning that the edges need to be well feathered so that the edges are no longer defined or obvious.

When you have to take a section or spot down to metal make sure the edges where the metal ends and the original primer or paint begins is blended smooth so that it is not pronounced.

Overall, you normally don't have to go all the way down to metal ( except of course in the case where you are trying to work out some rust spots ). If you were to take a brand new car to MAACO for a paint job, they will just sand the original paint so that it no longer has any gloss or shine to it. You could call it scruffing the paint, compared to sanding the paint, in that you are just scruffing the outer skin and coatings off the original paint - to provide a clean surface ( free of clear coat and free of any painted surface that might be bearing former wax and polish jobs ). It also is slightly scoring the surface so that the paint will have lots to adhere to...

If the rust area requires quite a bit of sanding - to the point that there is a significant differnce between the bottom of the rust sanded area and the top of the scruffed outer skin of the paint, then you might want to lay an extra layer of primer or two ( or maybe even a thin coat of bondo ) to level up the two surfaces.

Just remember the key concept here is that any imperfections in the smoothness of the hood, will be amplified when you start added layers of glossy and shiny paint. The paint job will not be filling in discrepancies between the surface smoothness. So the better you work the smoothness of the surface during prep.... the smoother and shinier the end paint job on that surface will be. The more time spent on the prep stage will add up to greater satisfaction with the overall job at the end of the project. This holds true whether you are rolling your paint or spraying it at a pro-paint shop.

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