I don’t believe that sand blasting will necessarily give you the best surface to apply your primer to. It certainly does remove paint and surface rust (mostly) but if you read the specifications provided by say PPG, they require a scratched surface usually caused by 80 grit sandpaper. Here are some pictures of sandblasted and scratched metal. You can see that the sandblasted surface leaves a “dented, concave” surface while a scratched surface leaves “edges” that the primer hangs on to. After you sandblast, sand the surface with 80 grit and you will get a better surface for the primer to adhere to.
As to the primer spray gun, you can buy a cheap Harbor Freight Purple gun on sale for about $10. Unfortunately, the tip is set for about 1.4. Primer requires a larger tip. The control rod in the gun is tapered so you can simply drill out the hole to the size you need and it will work fine. At $10, it’s almost a throwaway. I have been using this for years with good results.
1940 Chevy 1/2 Ton presently... Almost done 1940 Chevy Business Coupe... In pieces
