Remington 700 stainless bead blast question

[Lange]

Hello,

I was curious if anyone knows the grade of glass bead to match the factory finsh of the stainless 700s? I know its probably between medium or medium fine(80 -120?) but not sure exactly. Trying to touch up a 5r stainless and a few others but all seem to have the same finish. Will any brand work or do I need a specific band of bead to match. Had to buff a scratch out on the reciever and it got polished up. Also a mark on the bottom of reciever from the bedding block rubbing and mark on the bolt need a touch up blast I think. May do a bit on two other 700s as well. Likely wouldn't need 50 lbs I think, maybe <25 tops?

So just a small blast to blend is what im after. Never done this before so trying to find a abrasive blaster for air compressor etc. Also what PSI and distance away do I need to do?

Thank you

[Unclenick]

Normally you buy a blast cabinet. It recycles the same beads over and over, so they gradually get finer and that changes the finish results over time. Glass dust is a breathing hazard (silicosis is like the black lung of glass particles) so the cabinet contains the dust and has a filtering vacuum to draw the compressed air out. If you are doing something like this outdoors so the glass can wind up in the soil, don't do it where kids can breath the dust, stand up wind of the work and wear your own, good quality breathing filter. Hose down any dust you didn't catch on a tarp for re-use with water at the end of the work to get it under the thatch in the lawn so it can't blow around easily. The worms will then get it into the soil eventually.

This unit from Harbor Freight is one I got on sale on time, and it works well enough for the occasional use I have for it. I doubt it would survive in an industrial environment for long. Note the gun spec of 9.5 CFM@90 psi. They aren't kidding. That's a minimum for good work. My 5 hp cast iron, 80 gallon compressor can't keep up because it is just single-stage. I have to draw from that large tank until the compressor comes on, then let it catch up. If I had a do-over, I'd have saved up for a 2-stage compressor.

If you are blasting with a smaller unit and have smaller air flow, be prepared to spend a long, long time getting the job done and be prepared that getting the surface evenly blended is harder because of the small impact area. You will want to map out an overlapping sweep pattern in advance and stick to it. For long objects, like a barrel, get some wood and dowels and build a stand that suspends it between two dowel points and attach a scale at one end so you can index it the same amount each pass.

If your blaster it uses lower air pressure than 90-120 psi, be prepared that the particle velocity will be lower and this changes the surface finish result and makes you use more blasting beads to get the same job done. So it's not as simple as picking a grade. You need to match it to the blasting equipment and the air velocity you can achieve with it. Note that things like in-line water filters and long air hoses cut that velocity, too. On the other hand, if you have a beefy 2-stage compressor, regulating the output pressure (within the blast gun specs) gives you a little control of the appearance of the finish and you can experiment with that.

So, there are a bunch of factors involved. You will do best to try to get some 5 lb bags of media to try as small samples on a hidden area, like the underside of the barrel near the receiver, where the stock hides it, so you can see what your equipment does. If you can't get the impact velocity of the factory gear, you may never get an exact match from the same particle sizes they use anyway. Personally, I don't care if I get an absolutely exact match to factory as long as it is well-blended and uniform and looks good. There's nothing worse than stepping back and looking at the work in bright light and seeing lighter and darker areas because of uneven surface roughness due to uneven blasting or to one area being done with sharper beads than another. If you are feeding only fresh beads, that's easier, but costs you more in beads.

[tobnpr]

Never seen a 700 barrel in a satin finish- only polished SS- and you're never going to get a polished finish with glass beads, no matter how fine the mesh size.

[Unclenick]

A friend of mine had one of their mountain rifles in the late 1980's that had a satin/matte bead blasted finish, but it never occurred to me that it might be an aftermarket finish. I can't say I've ever gone shopping for a stainless 700.