If you're looking at mechanical stripping i.e. sanding, then look for a regular circular disk like a grinder to remove the majority of the old paint. It's much more aggressive than a DA.
It doesn't take as long and if more than one coat of paint is on your truck can cut the time in half compared to a DA.
Plus if you use one of those old 20lb 7" grinders you can skip the gym weights routine for the week!
Also if you find multi layers you can use 24 or 36 grit to cut and break up the top layers stopping before breaking through to the metal then switching to 80 or 100 for the rest.
Somewhere around this step I switch over to DA.
To get the pitted area you can use phosphoric acid (Ospho, Picklex, etc) but make sure to neutralized it properly if using epoxy primer.
Last edited by CASO; 04/08/2014 9:59 PM. Reason: underline
