Sandblasting Cost

I always used the 3M PPS cup system, it's a bladder style cup with no vent so you can spray upside down and never spill paint or run out until it's empty.

I'm not a painter but I've done a fair amount of painting on tube work and similar structures. Good prep, epoxy primer, and a good compatible paint makes for a very durable coating. Black epoxy primer under black paint has worked well for me and been insanely durable but can be sanded down easy enough for repairs and reshot.

I have used cup liners in my guns with good results for getting out of position.

Definitely gonna look into cup liners now. I went with a gray primer mainly just to help show any missed or light coverage spots.