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Bluing issues

Posted: Wed Dec 26, 2012 8:14 pm
by Franz20
Ok here's a complicated question.

I had an MG-34 1945 DOT/Israeli captured barrel shroud sent out for bluing.


Two things.

One: The guy bluing it for me called and informed me that the Nitre Salt bath was turning the shroud red. Is there something about the steel used? I'm thinking I will rust blue it myself.

Secondly: He has taken the shroud apart, which I am grateful, but I am guessing I will need new pins. What is the best source for these?

Re: Bluing issues

Posted: Wed Dec 26, 2012 9:24 pm
by www.Prussia.us
Red????????? Hmmm not sure, but for the pins try www.BRPGuns.com

Re: Bluing issues

Posted: Wed Dec 26, 2012 10:44 pm
by www.Prussia.us
I forgot to state, it is best to call Brian (the owner at BRP) sometimes those small pins are not listed on the website but he use to have them, Brian is a cool cat--he should be able to get you sorted out.

Re: Bluing issues

Posted: Sat Dec 29, 2012 3:31 pm
by Matt
Nitre salts blue at a temperature around 600 or 700 if I remember it right. Normal bluing is around 300. To high a temp will make hardened steel turn plum or deep purple. - matt

Re: Bluing issues

Posted: Sat Dec 29, 2012 5:46 pm
by DARIVS ARCHITECTVS
A steel that is high carbon and hardened, like a k98 Mauser extractor, will often turn coppery red when acid blued. I found that you can take that part and warm it to 130 degrees F. and dip it in cold bluing acid to darken it to just short of black. It's hard to predict what old parts will do when using nitre bluing. Sometimes they just get dark grey, sometimes flat black, sometimes plum. The concentration of the acid is important. If the solution gets weak, you get some bad results. And, as you probably know, preparation (cleaning all residues off) is the most important to getting an even finish from the process. Please understand that I am no expert in bluing, merely an amateur. I want to try my hand at old fashioned rust bluing on the next project, which takes some patience, but can yield better results than the mass production manufacturing shortcut of using nitre salts.

Re: Bluing issues

Posted: Mon Dec 31, 2012 6:03 pm
by Franz20
See, Rust blue, I understand. Though I would like to get this done "professionally".

Do you recommend someone who can blue (other than rust blue) my barrel shroud?



Thanks for the info!

Thanks!

Re: Bluing issues

Posted: Sun Jan 27, 2013 2:03 am
by Franz20
I know this may be slightly off topic but I want to show how a properly prepared firearm can look when rust blued. I used Pilkingtons rust blue solution.

http://i1240.photobucket.com/albums/gg4 ... aspx-1.jpg

http://i1240.photobucket.com/albums/gg4 ... aspx-3.jpg

Re: Bluing issues

Posted: Sun Jan 27, 2013 1:08 pm
by DARIVS ARCHITECTVS
That is awesome. It looks like original finish!

Hey guys, here is a short video from Midway USA on how to do old fashioned slow rust bluing.

http://www.youtube.com/watch?v=VPD3GWqk-yE