There are too many variables here to just say “no”.
1. What’s the end game? What are you looking to accomplish?
A.)Remove rust and corrosion?
B.) Pre-finishing (getting the dirt, grime and corrosion out of pits or engraving?
2. What’s type of media do you plan on using? Size and pressure matter.
A) glass beads? What grit/size
B) garnet?
C) aluminum oxide?
Blasting with the appropriate media and more importantly the correct pressure will NOT dimensionally change steel at all. Screws and pins included. It won’t even harm fine engraving.
If you are blasting to remove corrosion with the plan of properly polishing or brushing the steel after the blasting with the purpose of then finishing the metal either by blacking, re-casing, etc then yes, blasting is appropriate.
Especially if you are sending some of the pieces out to be hot blacked….you must remove ALL traces of rust, even the invisible stuff that hides in engraving and other nooks & crannies, if you don’t get this stuff out, you’ll later on have bleed out and it’ll spoil your new blacking.
If you are just blasting to blast…I’d say no, it’s not appropriate.
Using a very mild to fine media, at a mild velocity (psi) is the way to go. When it comes to double gun parts, lots of gunsmiths like using garnet or aluminum oxide. Glass beads can sometimes leave different “shades” on softer vs. hard steel. It really doesn’t matter if you’re blasting with the intent of polishing by hand afterwards.
After you’re done polishing or brushing the steel by hand and getting the pieces up to the appropriate sheen and you don’t plan on re-casing or blacking, it’s completely ok to either wax the parts or apply a clear lacquer to the parts for protection.
Hope this helps a little.
Dustin
