finish/blasting question

[jmforge]

So how fine do you have to finish hardened steel so that blasting with aluminum oxide media' etc will remove/hide the grinder marks? I have read that with old school rust bluing, a clean 320 grit finish will work without blasting,, but i have seen one guy take a blade up to 600 and hand sanded before blasting to prep for parkerizing. I have also read that the finer the finish you start with when rust bluing, the closer you will get to that back finish you see on the $100K plus English andf European shotguns. Does iut also work that way whn parkerizzing, etc? What UI am trying to figure out is how to get a good old school finizh,that is better qulaity than say Caswell, cold blue in a bottle or tool black.

 

[Edwardshandmadeknives]

I’m doing some rust blued fittings right now. My first time trying it, but so far I have found that a really smooth surface doesn’t work very well. The solution I was wetting it with beads up if it’s really smooth. I’m going to stick with 400. I know a guy that was sandblasting stainless and he finished it 36 grit belt, 320 grit greaseless compound, 600 grit greaseless compound, then sandblast, and it looked nice.

 

[REK Knives]

400 is what I've found