K frame refinishing and rebuild advice

It will be sandblasted totally clean. I was up at the resto shop today and brought it home to clean and paint. Is the por a brush on, if so does it come out smooth? I like the idea of sloshing it around inside.

Snake that was another option was the hi heat rattle can, but I would end up going thru about 6 or 7 cans and that starts to add up.