Stopping rust browning

[David Rase]

What methods do you guys use to "stop" the continuation of browning once you get the color and finish you desire?  In particular, all the residual surfaces in the inlet areas where the browning solution has made its way to the underside of the parts you were browning.  I have tried many methods over the years but always end up killing the browning 2 or 3 more times after initially ending the process.  This causes me to have to hold on to a firearm for several weeks while I periodically oil and rub down the areas with steel wool or wire brush just to make sure the browning process has stopped.  This gets to be annoying after so many rifles.
Thanks, David

[rich pierce]

I’m not sure a rhyme or reason can be discerned. Sometimes it persists. Sometimes no issue. I think the last application of solution should work a while in the theory it can get exhausted. Then a soapy wash with a bristle brush then carding then a soapy brush  wash again. Dry and then bristle brush with any sort of light oil. Mop with a white rag. Rinse and repeat. In time the rag will be white and you should be good to go.

[Eric Kettenburg]

I heat the part up until it's almost too hot to touch and then either dunk the entire part in ammonia or, in the case of a barrel, use a sloppy wet rag soaked with ammonia and just keep slathering it all over until the barrel is cool.  Sometime I may do it a second time.  Works for me - no after rusting at all.

[smart dog]

Hi Dave,
I now use the same method Eric described.  I used ammonia on the last 5 barrels I browned and it worked very well, even during some hot, humid days in summer.  I am sure the high humidity where you are does not help.  After stopping the browning and wiping with ammonia, and then applying oil to the warmed barrel, I let it sit for a couple days to see if any after rust still develops.  Also Dave, I tend to prefer really smooth, almost polished browning and bluing.  To accomplish that, I apply solution frequently and card after only 2 hours. In that process, I find that browning solution diluted with alcohol slows the rusting process producing a finer surface.  It also greatly reduces risk of after rust.

dave

[L. Akers]

With due respect to Rich,  I think there is a "rhyme or reason" for after-rust.  First, realize that a molecule of rust is larger than a molecule of steel and cannot physically occupy the same space.  The molecule of rust will grow out of the space originally occupied by the steel leaving a space under it.  Every commercial rust solution I have tried has been very strong, creating coarse, large-flaked red rust.  Large flakes= large pits.  Diluting the solution will give smaller flakes and smaller pits.  Microscopic flakes = microscopic pits.  I'm looking for a rust that is more tan than red in color.  Second, when carding it is imperative that ALL the rust is carded off.  It is impossible to do this with a piece of cloth.  Not removing all the rust is leaving those pits under the rust flakes covered by layers of loose oxide and a repository for residual browning solution (after-rust).  I use a steel-wire wheel (.005" dia. wires) in my drill press to card.  There will be a layer of oxide bonded to the steel at the atomic level that carding cannot remove.  It will eventually (about 2 weeks) become difficult to get rust to form and around this point I stop.  I flush the barrel with hot water from the tap for about 5 min. then flood the warm barrel with heavy gear oil and stand it on end in a corner.  Every day I flip the barrel end for end  then after a week wipe off excess oil.  The finish is dark chocolate brown, hard and rust resistant.  I have never had problems with after-rust with this process.

[David Rase]

Thanks for all the input.  I was on the eastern side of the state all day yesterday so I did not get a chance to read your input.  All answers are much appreciated.  I will digest the info and move forward.
David

[Craig Wilcox]

Mr. Akers, would boiling your finished product result in bluing the barrel? And it seems that your technique would work well on a finely polished barrel.
I, too, use that fine-bristled wheel on my drill press - they do a marvelous job.

[Mike Brooks]

Thanks for all the input.  I was on the eastern side of the state all day yesterday so I did not get a chance to read your input.  All answers are much appreciated.  I will digest the info and move forward.
David

I always get out my woo-woo stick and shaking it in a very vigorous manor yell three times "MAY THE POWER OF AMMONIA DEFEAT YOU!" Works every time.

[Darkhorse]

I stop the browning process in the bathtub using hot tap water (I turn up the hot water heater for this), and baking soda. Using a cloth and brush I really give it a good washing to make sure I saturate all the browning solution.
Then I dry the barrel and put on a heavy coat of oil and hang the barrel and lay out the small parts for a couple of days.
I've never had a problem with stopping the browning solution from working.

[L. Akers]

Mr. Akers, would boiling your finished product result in bluing the barrel? And it seems that your technique would work well on a finely polished barrel.
I, too, use that fine-bristled wheel on my drill press - they do a marvelous job.

Yes, boiling or soaking in boiling hot water will convert the red oxide to black.  My process for blackening is rust, boil, card.  I continue the process until it becomes difficult to get rust to form.  After the last carding I coat with gear oil.  A final rinse is not necessary because of the boiling step.  Highly polished barrels come out with the finish looking 6" deep.

[Craig Wilcox]

Many thanks, Sir.  Was thinking of using Brownell's hot salts bath, but that is a pain, for sure.  Quicker than rust bluing, but very costly for doing one barrel and some small parts.