Paul,
Got to thinking about it also. After you scuff up the hull make sure you wash it off really good to get all the dust and crap off it. I usually hit mine with the compressor. Depending on what you use to scuff it also it probably wouldn't hurt to blast it with some motor spray or at least rub it down with some rubbing alcohol. That will take of any oils or funky stuff that would cause the paint not to stick.

5150