Body filler is not designed to exceed 3mm thickness!!!!!
It is not designed in most cases to be applied over paint.
in this case I had to dig through one layer of base clear, filler, base clear candy over silver, filler, some sort of matte black or sealer, more primer and a final layer of filler. The tank is noticeably lighter now . Note to the world: if you repaint your metal parts , take time to strip it . If you are just doing a color change and don't have a repair filler is not needed . The basic rule to me has always been don't add bondo unless you have to.