doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Barrel prep before rust blueing question

I have everything just about ready to do my first rust blueing project and I'm in the process of buffing / polishing the barrel by hand. My question is how polished does it have to be? It does not have a mirror finish but is pretty good. I have a couple small areas that had some minor rust and I can still see the small pits. Should I file these out and then buff them? Some small areas look very shiny but others are not quite that good. Will this be noticable after it is blued? I'm using Pilkintons rust blueing solution.

I fired up the boiling tank tonight to try it out. It's a 38" gutter as described here a few weeks ago. I'm heating it on a camp stove. The water directly above the flame boils but the water on the ends does not. Will that be a problem?

Thank you in advance.

Tom, I'd hand polish these bbl's down to an 800 grit before starting to blue. Always polish from breech to muzzel. The rust will tone down the high sheen on the bbl to something in the 400/500 grir area . Ken

My gutter tanks do the same thing, boil in hot spots. It will be ok. I boil for half an hour.

I used to boil across 2 burners of the kitchen stove. No problem only getting boiling on the ends, water heat transfer is very fast. The water will be plenty hot in between burners for conversion. Even after the burners are shut off the water is hot enough for conversion. I don't know the lower threshold temp at which conversion happens, but it's got some tolerance, I'm guessing conversion will happen with water down to 190 ish.

Polishing to 600 grit is the minimum in my book. I like 800 better. I do my course polishing with well backed emory cloth lubed with wd40 or whatever is handy. Anything I touch with a file is not going to end up pretty.

Brent

Guess I'm just lazy but I never went finer than 400 grit for rust bluing. Also I do not use a buffing wheel, blends out too much of the writing/engraving etc & mighty hard to not round corners.

I go to 400 then fine wire wheel. I think the strength of the acid and length of the rusting period is at least as important as the degree of polish.
Steve

I have had trouble getting an even bite with the rusting solutions if going beyond ~320 grit, and I use a tightly controlled damp box. What I do is polish to 400 to be sure I have all of the scratches out and then hit it with 320 again. I even started hitting it in my bead blaster before the first rusting. This totally evens out any differences in the bare metal finish.

When I first started rust bluing I polished several small pieces of metal to different grit finishes and and then rusted them. I never could really see the difference between 320, 400, and 600. Well, except for the fact that the 600 grit piece was spotty, especially in the first few coats. Then when I started bead blasting after final polish, I rusted some small test pieces and could not tell which one was hand polished and which one was hand polished followed by blasting.

I have read in several places where the action of the rust is about equal to a 320 grit finish, so anything from 320 and up will look the same. Don't know how true this is and how this was judged. It oculd be one of those things that just gets repeated in gun books without any proof. i do know that each cycle of forming the oxidation layer on the steel, you are actually pitting the surface. As a mechanical engineer who has spent waaaaay too much time in the lab testing different materials, I have a hard time believing that the pitting action can be fine enough to see the difference in a 400, 600, or 800 grit finish. But I could be all wet here.

Anyway, You can control the finish by controlling the bite of each rust coat. If you let the parts get a very fine rust layer and do more cycles for the finish, then it will look noticeably different than a blue job where you do fewer cycles but let the rust really bite and build up heavier layers each time. THis will have the effect of looking "more polished," but all you are doing is controlling the physical pitting of the metal surface. I can't adequately stress how much you have control over the finished appearance of the blue by controlling the rust cycles. I have had people look at different pieces of my work and comment on how I polished them differently, but all it was is that on pieces I really did not care about I would just do fewer, but heavier, rustings. It comes out more matte and looks rougher. Also looks "blacker" rather than the "bluer" look of finer rustings.

I have said for years that I was going to do a controlled test of pieces of steel with different finishes and then keep then analyze them. I think I will definitely do it this year. Of course, I have said this too for several years, but I mean it this time!!! I am going to force myself to actually do the test in '07.

At any rate, i do beleive that the actual physical rusting of the steel is about 320 grit based on my observations. I know that it is much harder to get the rust to bite on steel that is polished to grits beyond 320. The higher the polish, the harder to get the bite. I am DEFINITELY not an expert in metal finishing by ANY stretch of the imagination, but men whom I respect have told me the same thing.

Just food for thought.

Oh yeah, almost forgot. If you can see pits now, you will see them in the finish. If they bother you, and you hav eenough metal there, then file them out and polish to match the rest of the gun. If it is in a thin spot on the barrels or something, then you may have to live with them.

As for your areas looking differently polished, it has been my experience than as you get to the 5th or 6th rust coat, then eveyrthing will look just like a 320 grit finish that has been risted. If you have any scratches that are more coarse than 320 grit, then they will show up through the blue, just as the pits will show through. As stated above, I blast the metal for an even finish, but truth be told I don't think it matters when going to 6 coats or beyond. But psychologically it helps me not worry as much, so I do it!

Marc,
Next time you try to rust something that is more highly polished, try putting on the first coat or two with a very slightly damp pad. That is, use just as little of the solution as possible. Go over the barrel many times with this very minimally damp pad. Once or twice like this and you should be getting even coverage thereafter. I've done this with a barrel polished to 1000 grit.

If you use less agressive solution, shorter times between boils and less humidity, you will get a more polished blue - if you start with more polished metal. It will take more applications however.

I'm no expert either but I have been doing a fair bit of blueing as I enjoy it for some reason.

Brent

Where was it that I read Parker Brothers only polished to 320 grit? It must have been in an article in a Double Gun Journal. Im usually happy with 600 grit, but often go to 800. As for a burner, I made my own out of angle iron and an old propane grills guts. My neighbor had an old grill sitting by his trash can so I went over and asked if I could "salvage" it. Ufnortunately the grill was rusting apart, otherwise I would have just set my tank right on top of it. I managed to get free valves, regulator, hose, couplings, and burner out of it though. Measured my tank and drew up some plans for my "station" and started welding. It works great and doesnt conflict with making dinner Ive also seen three burner cast iron camp stoves used for burners. That would be a quicker solution if you didnt want to make your own or use your stove top.

http://www.amazon.com/Cast-Triple-Burner-Propane-Stove/dp/B0000AXAAD