Im having ago at grit blasting a few painted metal parts. The large dark grey area is the blasted section and the shiny patches on the dark grey is where i have gone over it quick with a bit of 400 git paper. Basically, im not sure if the grit blasting is taking off all of the paint OR it is taking off all the paint but just leaving a dull slightly pitted surface. And then by rubbing it down with 400 brings in the shine? Is the metal ment to be all shiny straight after blasting?