browning over blue

[sarcasmn]

I tried the search and could not find the answer to this question. If I want to use LMF to brown a barrel, do I have to remove the factory blue first?

If I do have to remove the blue, whats the best way?

 

[Amikee]

I use airplane stripper from Autozone. Finish comes off like crazy. Be careful when you do it since it's highly acid-like and smell is terrible. Mask, thick rubber gloves and ventilated area are a must. Another way is to use steel wool, scotch brite works like a dream or just a wet sandpaper starting around 220 going to the highest grid you can. The better polish the better finish. Good luck whatever you decide.
I'm sure there are more ways.
Good luck

 

[Zonie]

It's possible that the LMF browning solution will bite thru the bluing but I think it will be kinda iffy.
The existing bluing has absorbed oil which really needs to be removed so just go ahead and remove it before you start.

If the existing bluing is degreased, just about any acid will remove it so you can use vinegar or lemon juice. Something made for removing rust like Navel Jelly will work and of course Birchwood Casey Blue & Rust Remover both are good.

It's been my experience that most browning agents including LMF's work best on surfaces that are slightly rough. If the surface is too smooth, they have difficulty "biting" into the steel to start the rusting process.

Due to this I do not recommend using a sandpaper finer than 220 grit.
A couple of sheets of the black "wet/dry" silicone carbide paper is made for use on steel parts and it is fairly inexpensive.
Buy some 180 or 220 grit.

If it were mine, I would just sand the existing bluing off. That way I know the surface is raw steel and it is ready for the browning solution.

Remember, LMF and the other similar browning agents need to work in a humid environment. A steamy bathroom is great.
A non steamy room in the house is iffy to say the least.

 

[sarcasmn]

Thanks for the tips. I live in Florida so a humid environment in the garage is never a problem. I used LMF on my GPR build. It took three coats for the rust to even start on that barrel. Now I suspect it was because I sanded the barrel so fine. I built a scalding tray to get the dark plum color. It took ten coats but the barrel came out beautiful and very smooth.

 

[huntsman247]

Vinegar will remove blueing and quickly; cheap too