Hi Roger
If I were you I would avoid sandblasting the tank. Sandblasting will hammer the surface and you risk deformation. Further, a lot of tin has been used when soldering the tank, especially in the front and in the back where the fastening bolt passes through the tank walls. Sandblasting tin is not very advisable. Instead of sandblasting, blasting with glass beads and steam is a much better and much more gentle method, and will not leave a surface full of craters.
As already mentioned, the tank must be painted with a good primer immediately after blasting. Wash well with cellulose thinner and dry thoroughly, preferrably with compressed air before applying primer. A modern etch-primer will be best. After sanding and preparing the surface to the best of your ability, apply a good surfacer and sand again with wet paper – type 800 and 1200. Apply surfacer again if necessary. A lot of time and patience spent at this stage is the most important contribution towards a perfect result.
Finally spray paint the dried and dust-free surface with a synthetic or acrylic paint compatible with the primer and surfacer used. These days I use acrylic paint 4 – 6 layers – then I apply the pinstriping and the transfers, and after that I apply 4 layers of clear acrylic lacquer. This gives a very strong and good-looking surface, and you can rub it and polish it without damaging the good looks – just like a cellulose lacquer.
I am just an amateur painter, but my experience is that with time and patience you can achieve an almost professional looking result.
Kind regards,
