Bluing vs. Browning

[Rusty_Nail]

Chemical questions for all...

Why does LMF rust the metal brown, then turn black when you hit it with boiling water, but BC starts black/deep blue then turns brown when you hit it with the same?

I was rebluing a Pedersoi KY barrel last night, and though it came out beautiful, it caught me off guard when it turned a nice brown! :thumbsup:

 

[Loyalist Dave]

According to the directions for Laurel Mountain Forge for browning and bluing...,

"Rust Blues are basically rust browns where the iron oxide (rust) has been converted from the Ferric Oxide state (Fe2O3), which is red, to the Ferric Ferrous Oxide state (Fe3O4), which is blue-black."

So this is why the LMF product reacts as it does, and I suspect the BC product starts out with Fe3O4, and converts it the other "direction" to Fe2O3.

LD

 

[Hemorad]

If I'm not mistaken, the Birchwood Casey browning solution (not their bluing solution) uses a hot brown process, requiring the metal part to be heated up prior to application. It also contains mercury. I'm not sure how much ferric or ferrous oxide comes into play with the BC product, as the brown is fairly instantaneous. I've used the BC stuff to quick-brown small parts, and it works quite well. Large parts like barrels tend to be a little patchy and inconsistent. I've also noted that after applying the BC liquid to a hot part, a nice brown color is imparted, but if you reheat the browned part with a torch, the brown finish appears to actually melt, and does change to a bluish black.

 

[Rusty_Nail]

The BC I used was PermaBlue. I did about 3 coats on the barrel after a dunk in boiling water and drying it. I put it on with a piece of white cotton sockd amp with the BC, to keep it from dripping. It dried at a somewhat brown hue.

I figured what the heck, in for a penny... If it turned out bad, I got bluing and rust remover in the kit! Kinda like an eraser on a pencil! :grin:

I decided to try the boiling water after carding with 0000 steel wool. Then I dried it, let it go a few to evaporate the moisture left, and did a coating of oil. Wiped off the excess, and did a coat of barricade.

It turned it a nice looking brown. And doesn't seem as easy to ding as normal cold bluing.

And I had numb fingertips until this afternoon because of handling a really hot barrel! :haha:

Just wanted to say thanks to all on here! If it wasn't for you guys, I never would have dared try! It was to redo a barrel on a gun that was messed up bad. I would post a pic or two how it turned out, but I got it in the classifieds if you want to see it.

 

[jdkerstetter]

Hey Rusty,

I can only speculate, but my bottle of BC Perma Blue's instructions specifically says rinse with cold water. Perhaps you confused it with the Plum Brown's instructions???

Likely what you did by applying it to a hot barrel and rinsing with hot water was cause some flash rusting, giving it the brown color. Never tried it hot, so don't know for sure.

Enjoy, J.D.

 

[Rusty_Nail]

Hey Rusty,

I can only speculate, but my bottle of BC Perma Blue's instructions specifically says rinse with cold water. Perhaps you confused it with the Plum Brown's instructions???

Confused it, no, just stupidly did not see the "cold".

So is it not a good thing, or just a variation of browning? It seems sealed well, and looks really nice. And doesn't come away on a cottom rag!

 

[Zonie]

If it doesn't rub off, it's the hard brown rust that makes browning a good choice.

Unless you don't like the results, I suggest you just accept it as it is.

 

[Bill Hall]

Sounds like flash rusting to me also. But hey, you may be on to something new there. :idunno: Bill

 

[jdkerstetter]

In response to a PT from Rusty I told him that I pulled the MSDS for both BC Perma Blue and Plum Brown. Both contain nitric acid, but the other chemicals vary.

Nitric acid is the main ingedient browning agents marketed by others as well and that is why I suspect he browned rather than blued the barrel by applying it hot.

If the barrel were boiled for a time, instead of just having boiling water applied, it might eventually kick the reaction over to blue in the same way cold brown is converted.

Enjoy, J.D.

 

[necchi]

Yeah it's got Nitric but also Cupric Sulfide,(sulfate?)
It's the copper element in the mix that makes that turns blue when it hit's the iron content of the steel barrel,
that's how "cold" blues work.
And I'm wondering if the hot water didn't make the copper do something funny.

Rusty, hold the barrel up to yer nose and take a wiff, Does it smell like a Penny?

 

[Rusty_Nail]

No Sir, no smell at all. And 5-6 wipes of the barrel with a white kleenex leaves no residue whatsoever. The barrel kept the shine of the metal, but is now a deep chocolate brown color!