Surface prep is a great question.  I checked one of my reference books "Composites" from ASM International.  They suggested cleaning the entire surface before sanding with hot soap and water, then rinse with tap water followed by a rinse in distilled water.  Next abrade with 240 grit paper, vacuuming (I'll assume you should wash the vacuum head to avoid contamination), swab with acetone and a clean gauze, rinse with distilled water, place in a forced air oven for an hour at 212 degrees F then bond immediately.

 

In the real world, I think we can dispense with the oven but the point is that the acetone isn't the problem.  I would just suggest using hardware store variety acetone.  It probably is OK but it does have significant and unquantified contaminates.  The contaminates at best won't harm the adhesion but I'd sure as Hell rather avoid them since the down side is adhesive failure.

 

One thing you should keep in mind is that there is a significant safety margin in our aircraft to allow for the lowest common denominator, i.e. a builder with poor skills and techniques.  In other words, if we were able to replicate structural parts and bonds to the highest levels of performance, our planes could be lighter still.

 

And I'm still looking for the temperature tables of sun on painted panels.  I'll send them out when I find 'Em.

 

Dan