I have a 17 foot Fisher aluminum bass boat that I want to repaint.  The problem I have is a lack of time.  Once I strip off the old paint, how quickly do I need to repaint?  Is there any harm in leaving it bare aluminum?  

Surface Preparation of Aluminum for Painting

Sand paper: 80-100 grit

Scotch-Brite Hand Pads: part # 7447

Conversion coating: acid etch primer/Alodine/Chemfilm

Paint: automotive or marine grade polyurethane

Paint & Coating Stripper: Eldorado Solutions' DoradoTM Industrial Products part # 2021 or 5051

Steps

010: Clean the aluminum surface with a good cleaner using Scotch-Brite Hand Pads to remove all dirt, old paint and oxide from the surface. When sanding I prefer 80-100 grit it gives better tooth and paint adhesion.  Sanding must be taken into the best previously adhered surface in order to have the new coat of paint hold properly. Start with an orbital sander; finish by hand with Scotch-Brite Hand Pads. Rinse thoroughly with clean water, let day completely.

020: Apply a coat of acid etch primer following the mixing and application instructions to the letter.

030: Within 24 hours of applying the etch primer, apply the topcoat finish.