[Mg-mmm] J2 gas tank sealer removal

[bill at clovermachine.com]

Back in ~1971 I had my J2 fuel tank de-rusted and internally sealed 
with the old zinc chromate (yellow) sealer; the stuff that is 
supposed to not stand up to todays ethanol gasoline.  47 years of 
just too busy to finish the restoration went by (good intentions are 
cheap). Hope to paint the J2 soon so the tank is now a priority.

I have been told by the local radiator/gas tank repair shop and Bill 
Hirsch automotive the old coating has to be removed as the new will 
not stick to it. 

The local radiator shop says to cut the tank open, bead blast/scrape 
out the old sealer, re-weld panels back and re coat. Bead or shot 
blast will warp metal if not careful.

Several YouTube videos suggest acetone or lacquer thinner (which is 
95% acetone) to clean motorcycle tanks. J2 tank is too large to be 
shaking and sloshing.

I doubt there is a better solution to this procedure, but thought I'd 
ask the group...Anyway, we need more activity on this MMM autox  
resource.

Bill
J2 3343