View Full Version : Barrel Finishing Help Needed.

August 28, 2010, 12:06 PM
I have a muzzleloader barrel 'in the white' and need some advice on finishing it.

In your opinion does the Birchwood Casey Plum Brown do a good job of browning a barrel? I want to go with a more authentic to period look. It's a St. Louis Hawken in 54 cal.

Should I cold blue it or use the Plum Brown to duplicate the rust finish?

August 28, 2010, 12:31 PM
Cold blue will leave a thin smelly blue coating that’s nothing like the "brown" look. … never used the BC plum brown.

Have you considered rust browning ? It takes "forever" or at least seems to, but looks great.

August 28, 2010, 12:42 PM
I finished a muzzle loader in plum brown. It took quite a few applications, but it worked, and the gun is still rust-free after 30+ years.

August 28, 2010, 12:53 PM
Many rifles back then were left "in the white", and over a few months/years aquired the brownish patina you are looking for, the result of surface rust wiped and oiled repeatedly until it is evenly colored because there is no more clean metal to rust. Very attractive, and that layer of rust actually protects the steel from further rust, kinda like bluing does.

Enter modern science. People trying to replicate the look and feel of authentic early 19th Century muzzleloaders need something to duplicate the look of old guns. Slight sidetrack: Rust bluing requires the use of chemicals that will give an even layer of surface rust, then you boil the metal to convert FeO2 (reddish-brown rust, ferrous oxide) to FeO1 (black iron oxide, ferric oxide). Repeat the treatment as necessary until there is no more exposed iron/steel to rust, and you're done. Effective, but very time-consuming and tedious, and requires some special ingredients. Neat find: you could just rust the steel and not boil it, and it would be browned, like old steel barrels. Or, like many did, you could bury the steel in your back yard for a while and retrieve it when you thought it was done. Not very controllable, but effective. There was also ammonia pickling, fuming sulfuric acid, perchlorate, and a variety of other compounds that would rust the barrel and allow the same look as patina.

Enter more modern science. As caustic bluing becomes more common, unavoidably someone scratched their blue job. Now they need something to "touch it up". Easily done, if you are a chemist. People are happy once more. And now the muzzleloaders want something, too! You can make the same type of compound as cold blue, but instead of it turning black, it turns dark brown. Works OK, looks OK. Voila! Fait accompli!

And that is pretty much what BC Plum Brown is, a cold "rust"-coloring process for steel. Does it work? No doubt. Does it look good? Pretty good, sure. Does it look authentic? Weeellllll, maybe.

August 28, 2010, 08:07 PM
The thing is ...

I've seen 2 barrels that were done with Plum Brown and one old Colonial Era rifle that was originally rust treated.

To be honest ... I can't really tell the difference between the two. The Plum Brown is a HOT process, and not a COLD one. You have to heat the metal to around 250 to 300 degrees and apply the compound. To me ... it's a cheap trick for rusting modern barrels, but it looks good from what I've seen.

I'm kind of leaning towards the Plum Brown just for the authentic look of it. At least with the Plum Brown I can control it somewhat. Unlike leaving my barrel in the yard for a few weeks. :p

August 29, 2010, 12:15 AM
I agree, it is effective and controllable. Look good? Sure. Authentic? Maybe.

As far as "hot" vs "cold", most cold blues work best when the metal is heated. I have seen Plum Brown applied at about 250-300 degrees, and it cleared out the shop in a short period. I have also seen it applied at about 180 degrees after heating in a water bath, and while obnoxious, it was easy to keep working. And that is still "cold" IMO. Remember to ventilate the area well.

In olden days, they used a lot of chemicals we would consider, um, "unfriendly". But BC Plum Brown will give you the desired rust look without the tedium of setting up a wooden box with a jar of fuming sulphuric acid and leaving it in the sun for a few days, carding off rust, putting it back in the box for a few days, repeating ad infinitum until the desired effect is achieved.

August 29, 2010, 08:10 AM
I've played a lot with the plum brown for metal patina, here some hints. First, all it is is nitric acid, you're just quick oxidizing the metal. Second, cold works just as well as hot, just take a long time. Third, make sure you degrease the barrel really well. I had some spotty results when just giving it a quick wipe with acetone.
And one remark to Scorch's excellent summary, the red iron oxide is Fe2O3, there is no FeO2 under normal circumstances.

August 29, 2010, 08:54 AM
Dude!!I just figured out a new way to plum-brown that sucker. First you take and make sure it's completely In the White meaning no sanding or rust removal necessary,take a can of bleachless brake cleaner and spray the barrel down thoroughly. The minute you get the can of breakcleaner emptied, dry it and take it into the local Sauna were they use salt water, and just set in there and relax!!:D Then let your adolescent son put it in his gym locker for a week!;) actually those are pretty silly ideas and that's probably Not what you were looking for. I appologize:( Seriously I have a friend that has an old BP rifle that he Browned and it's beautiful!;) He used the Birchwood Casey's Plum Browning solution.. And it's very very very nice, It looks old, and brown and thick.

August 29, 2010, 08:58 AM
So ... should I do it in my 2 car garage with the fan on and doors open, or is it an outside or shop kind of deal? Does it smell up the place pretty bad? Is it harmful to inhale the stuff coming off of the barrel?

August 29, 2010, 10:14 AM
I have had good results with Plum Brown.I used it many years ago(the post Jeremiah Johnson Hawken days)
At that time I was cautioned about a mercury ingredient(bichloride of mercury?)I don't know if it is still there,but think about what you breath and take care.When I got a bit carried away with humidity(shower stall) droplets formed and caused some aggresive etching.Don't go too high on polish.320 or so will work.
I have been using a Mark Lee solution,#2,I think,from Brownells,as my way to "bue"older style guns.I use a bluing tank full of water,boiling.I pull the part out,swab,then back in the water,then card,repeat till its right.I can do one in a few hours.It makes a rich,black coffee finish that I really like.
I then seal it with a turpentine-beeswax mix.(It doesn't mix all that well,but I rub it in hot.)

August 29, 2010, 10:18 AM
Here’s the MDSS for BC Plum Brown (not just nitric acid, but no mercury) :


Doesn’t really sound too bad. a supplied air respirator is recommended, though. If you got it, wear it. If you don’t have one and plan on using chemicals regularly, you need one, imo. Exposure dangers are all about concentration levels and a lot of that has to do with how well the area is ventilated and how close your face is to the piece.

I’d be tempted to set up at the open doorway of the garage on one side with a fan set up to blow into the garage on the other side so you get a gentle push of air from behind and no direct air on the piece, and wear the mask. That’s pretty much what I usually do for most icky fumes from acids to epoxies. Gettin older makes you appreciate your lungs more so I rarely go cowboy on the mask anymore … even when the stuff looks fairly innocuous like this stuff …
In the old days, I used to stack dust mask filters wetted with a mix of baking soda and water when messing with much stronger acid solutions, but can’t recommend that either for several reasons.

September 18, 2010, 08:16 PM
I have always been amazed (yes I am one of my mother's slower children) that blueing is controlled rust and that it is thought of as a rust preventer.

Good luck on your rifle