Sam8, Welcome to the addiction of Oldgas. In the areas of metal that is pitted but somewhat solid, you can use a high fill epoxy primer like PPG K36. Its a very easy sanding primer with high fill to build up and fill in the pits. As far as the cylinder goes, the is reproduction acrylic and glass avaliable at a reasonable price. I have never used an acrylic but I heard they have a tendancy to turn yellow over time especially when they kept outside.