We've had success in home-filling, and -painting - our tanks. I do get them professionally cleaned out (in Acid) - by a local company, called Metal Immersions. On the last job, Jay's D3 Bantam - he also welded up the leaks. After that, however - I filled in the dents, myself. This was with a product called "Newtech, space- age filler. Lots of wet and dry sanding. I use a lacquer paint series they sell, over here - called ColourPak. It's all in spray cans, no breathing apparatus needed. After the primer-surfacer and primer-filler - the saviour was Septone's "Blade Putty". This was for all the minor imperfections, in the surface. You can feel them, better - with your finger. Then about 5 coats of colour, the same with clear-coat. The end product was great. Lots of work, though