From experience I would not use por on any exterior surface.As for pinholes,WELD THEM or? duraglass or allmetal press into clean holes well (no air pocket).
The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself." - John Stuart Mill (1806 - 1873)
