polishing metal prior to bluing questions

[webradbury]

I am getting started on a Krag project. I have procured all my parts and have started polishing the metal and I have a few questions. The metal will be slow rust blued and I am looking for a quality finish so I know prep work and polishing is essential.

My questions:

1. How are pits and nicks corrected if they are too deep to file out. My receiver has a few very small places but i don't see taking that much metal off to correct them. Is there another acceptable method?

2. When polishing, how do you get rid of the really fine little scratches resulting from filing? I'm not trying to get a mirror finish in the bare metal but these little scratches run cross ways and every which way and stand out against the straight line polishing. (I hope that makes since)

3. If a surface is bead blasted and then rust blued (without polishing), what does the finish turn out like? Just curious...I was going to try this on some spare parts along with some other experiments.

Thanks in advance...Will

[Magana559]

Don't polish to a mirror finish because the acid won't spread even, it will just bead up and not rust evenly.
I usually just leave the pits alone. I also card off rust after the boil with denim, leaves a nice mate black look.

[Magana559]

Also bead blasting may not be the best idea, the blasting media might leave a protective residue and not allow it to rust.

[webradbury]

How smooth do you go? Do the tiny scratches stand out on a rust blue finish? I know they would be noticable on a shiny hot blue finish. I know I won't end up with a perfect finish like some high-end english double rifle but I try to do the best job possible.

[krit29-2]

No point in polishing finer than 320 grit as the rusting process etches the surface. And if you go to a ultra fine polish the rusting solution will pool and not stick to edges... I've used a ultra fine wirewheel to blend the surface before rusting..
If a surface is bead blasted and then rust blued (without polishing), what does the finish turn out like? Depends on how aggressive your blasting material is.....and how/ what your carding with.. I've used Glass Beads with a wheel card and the finish came out something like a Remington SP finish.
How are pits and nicks corrected if they are too deep to file out? three choices, well four actually.. weld and reform, light hammer strikes to deform and fill around the nick/pit the best you can, then re-file , or keep fileing and hope for the best trying to blend everything , or lastly.. just live with it......

[John 242]

How smooth do you go? Do the tiny scratches stand out on a rust blue finish? I know they would be noticable on a shiny hot blue finish. I know I won't end up with a perfect finish like some high-end english double rifle but I try to do the best job possible.

I stop at 400 grit as I was taught that a finer finish was counter productive. There are apparently ways to get a finer finish than 400, like on some fine European guns, but not at my skill level. 400 works for me and looks great.

I really wouldn't say that rust bluing "hides" anything, but it doesn't show every scratch like something buffed to a high shine. Well, in my opinion, anyway.
(I caustic blued a couple of rifles with lots of heavy pitting recently. Even blasting with 120 grit aluminum oxide didn't "hide" as much as you'd think. I'm kind of picky, though.)

You mention fine scratches from filing...
How I remove pits is typically with as small of a file as possible. If I can, I'll use a 4 inch smooth. I'll follow my filling with successively finer sandpaper, usually changing directions per grit change (cross polishing), until I have a satisfactory finish without gritters (deep scratches left from filing or sanding). The idea is to remove the previous grits scratches with the next finer grit, if that makes sense. Soft stones like the Die Maker's set from Gesswein are great for getting into hard to file/sand areas and they can be shaped on a grinder.
Gray Scotch Brite works great at cleaning up fine scratches, as will a carding wheel with .0025 wire.

Bad pits or dings could be TIG welded, depending on their location, but that creates its own headaches and is probably beyond the scope of what you're trying to accomplish.

I have never bead blasted and then rust blued, so I can't comment on that. However, glass beads do a good job of hiding fine scratches and is really cool looking if followed up with a wire wheel and caustic blued.

[nhrifle]

Others on here can correct me if I am wrong, but here's my take. Bluing definitely doesn't hide any imperfections, in fact I have often found pits or scratches after bluing that I couldn't see on bare polished steel, and the higher the polish, the greater the magnification. However, there comes a point where you may have to live with whatever pits or scratches are there so as not to remove too much metal in critical areas. Most scratches and pits can be removed with careful work using abrasives, a file is something I use for bulk removal. Emery Cloth used in a "shoe shine" fashion does wonders and is actually quite speedy. One of my favorite tools is the emery boards folks use to smooth out their fingernails. Problem areas can be sort of blended and made less visible with a wire wheel mounted on a bench grinder.

[2ndAmendmentNut]

107257

This model 10-10 I polished to a really fine 1200-1500grit. Then scuffed the entire gun with the "grain" of the metal using 400grit. Making the finish much smoother than needed and then using 400grit paper gave me a more uniform finish.

[oldred]

How deep are those file marks? Properly done file marks should easily disappear with fairly light sanding, are you using a good sharp nick free file and are "chalking" it or attempting to file "dry"?

[gnoahhh]

I assume you're talking about draw filing the barrel? Work down through the grits after filing until you reach 400x. That should be plenty fine enough. I sometimes go to 600x if I want a little finer finish, but I'm careful to replace the 600 paper when it starts to wear smooth so as not to make the surface any smoother than practical (see above comments re: solution puddling). When I do go to 600, I go through a lot of 600 paper.

If you're talking about pits in the receiver, I would stone them out rather than file. Remember, those receivers are case hardened glass-hard on their surfaces. Not fertile ground for filing. I recently acquired a Krag varminter that a previous owner electro-penciled his social security number on the left side right above the wood line. Progressively finer stones made it disappear (mostly with rubber based polishing "stones" so as to maintain the camber of the steel surface). Since the rest of the receiver finish was immaculate I didn't want to refinish the whole thing- luckily Oxpho Blue blended it right in. Totally un-noticeable now.

[johnson1942]

beadblasting and rust blueing go together. a deep long lasting matte finish is what you will get that looks good and really lasts. after it is all done, rub in floor wax and the finish will be water resistant and really look good.

[Frank46]

If the pits are not really big ones then use a sharpening stone so you can follow the radius of the receiver. That is what I did on a 1888 commission rifle. Got all the little pits out and had to resort to using tool makers stones. There are no bumps, divots, or low spots on the receiver and all markings are still there. Then if you wish start with 220 silicon carbide paper and finish up with either 320 or 400max grit. Frank