Rust Blue Question

[porchdog48]

I am in the process of rust bluing a barrel, and have a question if what I am seeing is normal or not. I finished the barrel flats to 400 grit. Then applied a coat of Laurel browning solution then a second coat 3 hours later. Waited 6 hours and had a nice even coat of rust. Then put barrel in a tank of distilled water that was just below boiling. The barrel turned blue/black. Carded off barrel with 4/0 cleaned steel wool, and reapplied browning solution. Let the barrel sit for 6 more hours, and got a surface that looks like rust only is black like a coat of soot. Is this normal or should I be getting an actual rust coating. Humidity here today is 87%. Has anyone else experienced this or what am I doing wrong.


Dave 

[eddillon]

I use LMF cut 50/50 with distilled water.  I wait 4 hours before dipping in boiling distilled water.  Let it sit for about 30-45 minutes.  Take it out and very lightly card w/4-0000.  Repeat 4X or what ever color pleases you.  Each time I get the sooty residue.  I wipe off with paper towel before re-applying LMF.  Very happy with results.  Mt setup is a 48" length of 3" PVC with a cap on the bottom.  I set it up so that is perfectly vertical.  I don't drill the flash hole until after bluing.  I suspend the barrel and tang on a plastic coated coat hanger dead center in my vertical set up.  Pour in boiling distilled water and wait the 30-45 minutes.  Very stressless process.  No bad rusting in the bore.

[kutter]

Sometimes the repeated coatings with LM solution won't be red-rust color. They'll be black, blue in color instead  w/a hint of red. I'm no chemist so I don't know the answer as to why.
But as long as there is a new coating formed (you can see it and feel it),,it'll build another layer of color if you just continue to boil and card as usual.
I lightly,,very lightly swipe a finger accross the surface of the freshly rusted part(s) to check them to see if they are ready. It's easier for me to tell by the feel of the coating than the look.

Maybe it's just that the color if the previous blue is showing through, You really don't need a thick heavy rust layer to add another coating of blue color.
If you use LM or most any other cold rust soln over old existing rust blue, it won't look red either. Just blue/black usually w/a hint of brown. Some red rust in the areas that you may have touch up polished.
But it still builds up color on those areas.

At one time I was concerned of the same thing and added an extra coating of the solution betw boilings thinking it HAD to be red colored to be real rust. All it does is muddy up your water quicker and possibly etch the surface more (maybe something you want,,maybe not).

It takes just a very fine rusting to create a blue coating. Extra heavy coats of rust don't accomplish much for you if you're after a nice even fine grained finish.

[porchdog48]

Thanks for the replies. The lack of a rust color had me worried. I am on my 4th coat and the color is getting gradually darker. I just did not want to keep going if I was wrong. I appreciate the quick response. This is a great forum I have learned much, and just wish I had more experience so I could contribute.


Dave 

 

[eddillon]

Dave,
When the humidity is that high, your 400# will be for naught if you leave the solution so long.  High humidity produces coarse etched surface. 

[PPatch]

Good thread and excellent answers guys. I will be rust bluing my barrel soon and this was good to know.

dp

[eddillon]

Once you get the hang of it you will ask yourself why you haven't been doing it all along!  I swear by my vertical PVC tank

[b bogart]

I did one the way Mr Dillion has explained and it turned out wonderful except for one tiny spot. That was more than likely operator error. I was suprised how simple it was and how well it worked.

[Dphariss]

Thanks for the replies. The lack of a rust color had me worried. I am on my 4th coat and the color is getting gradually darker. I just did not want to keep going if I was wrong. I appreciate the quick response. This is a great forum I have learned much, and just wish I had more experience so I could contribute.


Dave 

 

If the solution has much nitric acid in it the solution will tend to turn the metal blue on application. I would not worry about the color before boil out and carding. How it looks AFTER the carding is the only real concern.
If the solution is too strong it can be a rust remover and will pit excessively. Weak solutions, in my experience, work poorly in low humidity. But too strong is a really bad idea.
Polishing past 320 for rust blue is extra work, slows the rusting process, makes it harder to get an even first coat and does not improve to look of the barrel when its done. 320 is fine leaving it to rough, like a 220 from a fresh sheet, may show in the final job. The trick is getting all the previous grit marks out.
Hot tank bluing will benefit from a better polish. Browning and rust blue will not in my experience.

Dan

[KentSmith]

The black is just another oxide of iron - either iron(II) oxide or iron(III) oxide I would think most probably the first.  Like the rust (hydrated iron oxide) I could be carded off.  I am not a chemist but the father of a chemist so some of that stuff managed to stick.  I'd ask her for clarification but fall asleep during the dissertation.  The black doesn't hurt anything and can be ignored as stated above.

[hortonstn]

after reading these posts i have to ask a question?,
when i rust blue i use danglers rust blue i do it just like i brown, putting on seversl coats over a week ot two time period, then i boil in a hot tank for 15-20 min
then card and use mineral-oil let it set a day or two then if i have to ill give it a
baking soda bath is this wrong? i've had very good results
thanks
paul

[Meteorman]

I am the son of a Phd organic chemist and i can assure you: such knowledge is NOT inherited. 
Anyway, when i use LMF, i find the early appearing "black stuff" to be good.
It turns to, or at least precursors, red rust in 10 or so more hours.
No black stuff?  That usually means the dreaded coppering, in my experience, and no rusting until rubbed off and re-applied.
When rust blueing with LMF, i personally dont boil until after the last rusting phase.
/mike

[porchdog48]

I just wanted to post an update. I have completed 8 cycles of the bluing process and I could not be happier with the results. I would like to thank everyone for all the helpful information. I did find out that I was not leaving the barrel in the water long enough. I would put it in the water for about 5 minutes then remove let cool , and then card. The last two cycles I left in the water for 30 minutes, turning the heat off after the first 5 minutes, removing and carded when barrel was cool enough to handle. The soot like covering came off with less rubbing and the color evened out and was much darker. Once again thank you all very much.

Dave 

[Long John]

When you perform a rust blue with boiling water what you are doing is converting the red/brown ferrric oxide, Fe₂O₃, into ferrosoferric oxide hydrate, Fe₃O₄ - XH₂O where X, is a number from 2 to 9.  Ferrosoferric oxide hydrates are a deep blue/black color and are very stable once formed.

Best Regards,

John Cholin

[doug.brayman]

I'm very interested in trying this. Does anyone have pics to share of rust blued parts?

[Rolf]

I'm very interested in trying this. Does anyone have pics to share of rust blued parts?

This is a rust blued entry pipe with silver accents for a long barreled pistol I'm building.


Barrels on theses pistols are rust blued with a home brewed solution of ironcloride and alcohol.
http://americanlongrifles.org/forum/index.php?topic=14643.0

Here is a link to some rust bluing experiments I did.
http://americanlongrifles.org/forum/index.php?topic=9755.msg92094#msg92094

Best regards
Rolf

[doug.brayman]

Wow! I really like that.

[Darrin McDonal]

Now I will start by saying I havent used LMF for rust blurring but I have done a lot of rust blueing with Mark Lee rust blueing and the process is the same. When I do it I heat the bbl to hot but not to where the water will boil. Then apply the solution to cause the rusting. There is no waiting to submerge the barrel in the boiling water. Remove from water and tilt up immediately and dab any drops with a paper towel. Card off the oxide and repeat right away. No waiting. Repeat 4-5 times, your done. This the condensed explanation.
Works great, ask Mark Silver.
Darrin

[kutter]

Mark Lee's solution is a Quick Rust Blue (sometimes called a Hot Rust Blue)
Laurel Mountain is a Cold Rust Blue.

The similarity is that the boiling water changes the red rust to a black oxide.

The difference is in the creation of the rust coating.

Quick rust is instant. High heat is the generator. I use a propane torch instead of the hot water to heat the parts but the results can be the same.
Lots of old formulas are Quick Rust blues.

Cold Rust Blue the rusting is natural, but can be accelerated by increasing the air temp and humidity (within some boundrys usually).

Most anything that will cause steel to rust can be used as a 'cold rust blue (or brown) solution.
Salt water is one. Weak soln of Muriatic acid works well. SalAmmoniac flux disolved in water (get in a small bar at welder supply places still. I used that one early on.
But they generally won't do double duty as a Quick Rust Blue solution as well.


Some people say the cold rust blue is a tougher finish.  That's a separate debate and I think depends on the steel type and frankly how well the bluing job was done.
My experience has been the some metal will blue better with one than the other. If one doesn't work too well, try another formular of the same type (hot rust for example). If that doesn't do it change over to the other style finish.

I use both Mark Lee's and Laurel Mtn. Have for at least 25yrs or more.
I've used a great many different ones and these two I've finally settled on. No complaints in all those years. If I had any, I'd still be searching.
Use what ever gets you the results you are satisfied with.

They both have a place especially when trying to match an older finish or patch one. Sometimes I use both on the same project.
Most new work I use Laurel Mtn but that's not written in stone either.

[Darrin McDonal]

Very good explanation Kutter. I am very happy with the Mark Lee solution and since it is  big bottle, it'll be in use for quite some time. I really like LMF cold blue also. I will try using it in a blueing application. I have no doubts it will work well.
Darrin

[wilkie]

I believe I have posted this before but I have used Brownells dicropan im hot water bluing but found that I could skip the boiling hot water.  All you have to do is polish the way u want it, degrease with lac thinner or acetone, apply im solution, let set a day, use 0000 steel wool to remove the surface rust, repeat im application.  It takes about 4 to 6 coats depending on the kind of steel.  I use a tooth brush to apply solution but It doesn't take much for each coat.  If you polish to shiney surface you will get a shiney blued surface.  This produces a black oxide coating that gets more wear resistant with time.  I've used it to reblue places on caustic blued modern guns and u can't tell the difference between the two coatings.  It is easy to do and doesn't take a lot of time for each coat.  If the finish gets scratched you can degrease and recoat without removing the old bluing.  Sometimes the surface of cold rolled steel will have to be polished to take the bluing evenly.  The first 2 or 3 coats will have a rusty surface but after that the surface will not have much of a red rust coating, only a black oxide coating.  Brownells doesn't say it works without the boiling water but I have used it for several years with excellent results.