Rust bluing troubles -- rust stays red after boiling.

[oldred]

Never polish past 240 grit. Also I hand polish only GW

That's not the first time I have heard that suggested but I was always afraid that it would not produce a smooth enough finish however I think I am going to give that a try, I have been polishing down to 320 grit but your post has me convinced I need to try some ML parts I am working on right now to only go to the 240 stage.

This is turning into a very informative discussion, thanks to the OP for bring it it up.

[gnoahhh]

I always go to at least 400grit, sometimes 600. Personal preference. Never ever had a problem with the solution not 'taking'.

[Tazman1602]

Haven't read all the posts but I can tell you this from years of blueing with Brownells Oxynate #7. If the blue turns a bit red after it comes out of the tank and boiling, that is a clear indication you let the blueing solution get too hot. Easy to do if you are distracted for even a minute..................

............and don't ask how I know that............................

Art

[KCSO]

Your metal may be the problem too. Some of the steels used in earlier guns just did not blue well with common bluing solutions. A purple color was common on for instance 94 Winchester receivers.

[kencha]

Another update...

After starting over the 2nd time on the frame/barrel/cylinder, I think I've found success. For whatever reason, those parts never did completely convert from red to black during the boiling, after the first pass. Unfortunately, I didn't ever figure that out. The small parts all converted well, and I would be carding off black velvet. The large parts, I'd be carding off red.

But, if I let them rust long enough, they'd still be darker underneath after carding. So I think my biggest problem was not letting them rust long enough.

Earlier, I was afraid to let them rust too long for fear of pitting. On the 2nd attempt, the first pass went as normal. Converted and carded to a gunmetal gray. The 2nd pass, I thoroughly degreased again (probably not necessary, but I was getting desperate) and used the Pilkington's. This time, I decided I wouldn't boil it until it had a good coat of rust. It ended up sitting for 36 hours! While the small parts would develop a coat of rust in 3-5 hours, it took a full day and a half for the large parts, in very similar heat/humidity conditions. And we're not talking heavy rust. It just had a strong, dark orange hue over the entire treated part.

The following 2 passes I used the Brownell's, and after being left for 24 hours it developed a coat over the whole part.

Upon boiling, there would still be some orange remaining, but there was conversion too.

I'm not wanting a jet black coating, so I think I'm going to stop there. I have it sitting in oil now, and will clean and assemble tomorrow. If I'm not happy with it, I can always degrease and run another pass or two.

So, for anyone thinking about giving it a try, my suggestion FWIW would be to follow the instructions carefully.
Degrease THOROUGHLY (unless you're using Laurel Mountain, I guess).
Apply SPARINGLY (They mean it. If it doesn't practically flash off as an even coat, you're using too much and end up with uneven rusting.)
And, most importantly for me, actually let it rust.

[gnoahhh]

Are you using a damp box to rust your parts inside of? If you're relying on ambient humidity to induce rusting, it's not as controllable/predictable as when using a purpose-built cabinet/box. I have never had to wait 36 hours to get a uniform coat of rust. Often I can get 4 cycles accomplished in a (long) day, but then again I use a damp box with a heat source to generate atmospheric moisture (using distilled water), and have done so from day one. I found that a thermometer inside the box to be sufficient for giving consistent results. A humidity gauge would be handy, but I'm too cheap. I keep a consistent temp, and monitor the parts so as not to let them get too rusty.

There's as much of a feel/sense of art to this as there is pure science.

[David2011]

Just a thought. I've always used reverse osmosis purified water instead of distilled water that may have contacted copper tubing during the distallaton process. In hot bluing any amount of copper can cause problems.

David

[kencha]

It is finished. Not perfect, but I didn't want it to be. The coloring is nice and even though. I just didn't polish it all that well as I didn't want to lose the machining marks, upset metal from the stampings, or some of the character marks.

I did think about getting an aquarium water de-ionizer to try to fix the poor conversion during boiling, but the small parts all processed fine under the exact same conditions, at the same time, with the same water, etc, so I took that as meaning the water wasn't my issue.

They were rusted in a very small bathroom where I set up a heater and left some wet towels hanging. Temp was always 76-85F, and humidity stayed around 70-80% according to a really cheap, and possibly inaccurate, hygrometer.

The same conditions were used throughout the process, both the first time around and the 2nd when I redid just the large parts.

For whatever reason, the large parts simply refused to rust after the first pass. Both times, the first pass worked just as expected on the large parts. The failure of the first attempt was, I think, due to me not waiting long enough on successive passes. But there never was good, full conversion of red->black during boiling on the large parts after the first pass during either attempt. I'll just have to assume it is due to the metal used. I don't understand how that would cause poor conversion. I would think that if it could rust, that rust could be converted. But I won't lose any more sleep over it.

I was able to get them to rust quicker if I applied the solution heavier, but it would end up being very uneven, causing heavy rust spots on some areas (where the last of the solution evaporated) before there was even any visible rust on others.

Thanks for everyones input. I'll definitely do it again if I come across another beater. I've even been keeping an eye out at the LGS and pawn shops looking for another cheap beater to reblue.

[22cf45]

For what its worth, my experience with rust blueing has been good. I've done maybe 20-30 rifles and shotguns, no revolvers or pistols. I buff to 400 grit on a wheel and then hand sand lightly with 600 to remove the squigly lines from the wheel. I don't see any difference between Pilkingtons or Brownells except cost, so I use Brownells. I don't like Mark Lee and haven't tried Laural Mountain. I use RO water and stainless tanks to boil. If the humidity is low, I've got a long plastic box that I think women use to store wrapping paper, after putting the parts in the box, I place 2 or 3 cups with hot water in the box and close the lid. I boil when I see only slight amounts of rust appear since I don't want deep pock marks and a matte looking finish. I don't bother with suspending the parts in the water, I just lay them square on the bottom of the tank and I don't put the parts in until I've got a good boil going. I boil maybe 5 minutes, card, apply the rusting solution, and go again until I've got the color I want. Generally it takes around 8 times. Always check the bluing in bright sunlight before I stop.

I have had the red color remaining after boiling a few times. I just card it off and keep going. So far it has always worked out. The rifles and shotguns I have done have ranged from the 1880's to present modern steel. I've seen no difference.
Your mileage may vary,
Phil

[rattletrap1970]

I use Mark Lee Express Blue. I degrease the metal, warm it with a torch (just so it evaporates fast), then boil in filtered City Tap Water. Longer time on thicker parts (you want the part to get to the temp of the water). Then Card. Then repeat. 6 Times is usually enough for me.

[22cf45]

The reason I said I didn't like Mark Lee is that after I had gone thru the procedure with Mark Lee 8 times, I took it out into the sun and could see thru the blue. It looked great under artificial light but not so in the sun. I grabbed the Brownells and finished it up. Maybe I should have kept going.
Phil

[rattletrap1970]

I've done many many guns with Express blue. I have never, ever had that problem. There is nothing to see through. I think the effect you are describing is simply not enough iterations of bluing. The frame I showed a picture of was 6 hits and I stopped because it simply wouldn't rust anymore with the solution. And it is this black in any light.

[johnson1942]

i rustblued a leaded steel barrel and it turned out somewhat mottled and looked very very antique.it was on a custom 1840/s muzzle loader i was building. it did not turn out as i had it was supposed to but the more i looked at it i finally realized it was perfect for a antique looking gun. i did everything right , even the boiling but i will only do that again if i want it to look antique.

[HDS]

I have a rust bluing question thats not really related to the OP but I don't want to make a new thread for it. I wonder what kinda final finish will I have if I rust blue a bead blasted and matte surface? Will it be bead blasted and matte still, or will the surface smooth out and become more normal?

I'm interested in refinishing my 870 express with rust bluing and give it a non-matte finish that looks more like a traditional wingmaster finish.

[rattletrap1970]

You can mirror polish metal and then rust blue it BUT, the rust bluing process is a caustic (mildly) process that imparts it's own finish. Hard to explain except that is smooths out (mildly) light sanding and un mirrors a mirror finish. Kind of the shinier side of satin-izes whatever you are working on.

Hot caustic bluing (what gun makers use) is similar to this recipe I have:

5 Pounds Sodium Hydroxide (lye)
4 Pounds Sodium Nitrate (Nitrate of Soda)
2 Gallons of Distilled Water

This is brought up to 253-256 degrees F and parts are immersed for about 30 min. It's a much more dangerous and finicky process, but, you can get your black mirror finish.

[HDS]

I was hoping for the satin like finish actually, I was mostly wondering if I could put the parts in my cabinet and bead blast them, or if I needed to polish the surfaces by hand with something like 320 or 400 grit paper to get that finish.