I think a lot of this is about long term storage of unpainted items and how to keep them fresh. In talking with my PPG representatives here, after cleaning the sandblasting dust off with DX330, do it right, and do it thoroughly, DPLF and K36. They KNOW what the PPG hotline says.. but they say do NOTHING that requires a WATER rinse. Why put water? on your metal when you are worried about your humidity? They also say K36 years later will be fine for applying filler, etc. Its all arguable though. You will do what you feel is best and it will all work out.
On sealer.. experts agree it isn't necessary, its just prudent. If you stop at 400 grit paper before finish painting, the sealer fills 320 grit and above scratches completely. This is just cheap insurance that your scratches aren't going to come back to bite you. The added benefit of it being epoxy sealer so you are effectively sandwiching in the process.
Any of the suggestions in this thread will make for a 'Riddler'. But what makes this possible is knowing what you are doing in the application process. This is what scares the crap out of me.. every time I step into the paint room! Will I be good enough in my technique to not run the paint, or whatever on that particular day? I certainly hope so.
