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Posted By: Quail Hunter 01 rust bluing durability - 04/08/13 12:40 PM
Just purchased a Franchi SLE, proofed in 1957 and while gun is very light used, the rust blueing on both barels where gun has been carried is getting thin.

Comments on the durability of rust blueing vs chemical blueing welcome.
Posted By: TwiceBarrel Re: rust bluing durability - 04/08/13 02:06 PM
Thinning or removal of bluing is cased by abrasion, chemical reaction or a combination of both. Both rust bluing and "hot" bluing are subject to both. I have several 100 year old Foxes and Lefevers that were rust blued and retain 95% +/- of their original bluing so I suspect that on a well cared for gun "hot" bluing has no advantage over rust bluing.
Posted By: PA24 Re: rust bluing durability - 04/08/13 02:25 PM


Human sweat will damage over time any blueing, case colors or wood finish on firearms....always has, always will....

Human sweat contains numerous minerals, lactate and urea....mineral composition varies with the individual....

Sweat minerals usually contain, in varied amounts, the following trace elements: sodium, potassium, magnesium, calcium, zinc, copper, iron, chromium, nickel, lead and probably many other less abundant trace elements leave the body through sweating with varying lower concentrations.....

Years ago, new Browning and other firearms always contained a hang tag that recommended wiping down a firearm "immediately" after handling to remove fingerprints which damage the finish, they even supplied the gun cloth with each new gun for that purpose.......the above text was the reason......

Posted By: LeFusil Re: rust bluing durability - 04/08/13 04:39 PM
There is a world renowned rifle maker in Cache Valley Utah that tested different types of bluing (different rust blue formulas, hot blue formulas, I believe even carbonia bluing). Same steel type, etc. put the pieces of steel in a tumbler, sprayed them with mild salt solution, etc. Basically torture tested the finishes. The hot salt bluing in which the salts were changed frequently or new came out on top every time. Guess which finish is used on his $22k custom rifles?

Like what was said earlier, sweat and natural body oils found on the hands, etc are terrible for any type of bluing.
Posted By: Nick. C Re: rust bluing durability - 04/08/13 06:20 PM
LeFusil, I'm not doubting what you say at all but did the maker in question publish any of his findings ? I'd always been under the impression that rust blue was more durable but always have an open mind. I've seen the tests done to firearms for the military grades of rust protection and wonder if these are similar to what he subjected the parts to.
Coincidently, I've found that blood can remove some blueing pretty quickly .
Posted By: LeFusil Re: rust bluing durability - 04/08/13 07:46 PM
No, he did not publish the results from his testing. I imagine his motive for the testing was to find out what the most durable finish might be while still keeping the end product classy. I'm sure he could have his stuff coated with Black T, Roguard, NP3, etc. but in the end, he probably feels that those finishes just wouldn't look right on his guns. I did hear that he didn't like how his rifles looked after his clients would come back from Africa, that is what prompted his testing of different blued finishes.
Over the years, I've come to the conclusion that hot blued parts do seem to hold color longer than rust blued parts. Especially on bits like, trigger guard tangs, forend irons, top levers, safety buttons and floor plates. Using fresh salts and good metal prep are course key in the quality of the finished product.
Posted By: drduc Re: rust bluing durability - 04/08/13 09:33 PM
Blood will PIT stainless steel surgical instruments very quickly. I do mean pit and I do mean quickly. Ask me how I know.
Posted By: PA24 Re: rust bluing durability - 04/08/13 10:10 PM


Originally Posted By: LeFusil

Over the years, I've come to the conclusion that hot blued parts do seem to hold color longer than rust blued parts. Especially on bits like, trigger guard tangs, forend irons, top levers, safety buttons and floor plates. Using fresh salts and good metal prep are course key in the quality of the finished product.


If rust blued parts are correctly prepped and rust blued in a "boiling hot water tank process" instead of the "old cold sweat box process" .........then, because of the heat penetration of the rust oxide during the boiling process, i.e. open steel pores and deeper penetration, and the numerous multiple coats and boilings, it has been my experience that a good rust blueing will out last and out wear the hot salt tank blueing process in most cases.......

Key word in all of this, is the word HOT..........

And yes, blood is the best blueing remover there is.....it is also great for pitting and ruining firearms....... always very interesting watching folks lay dead critters on their prized guns for the 'ol Kodak moment.......

Posted By: Kutter Re: rust bluing durability - 04/09/13 02:41 PM
There are so many variables involved including the person doing the bluing.
The type of steel being blued has a lot to say with how well the completed finish stands up to handling and wear.
The older & softer steel bbls and parts blue much better as far as durability goes.

Some modern alloys seem to resist most classic rustblues but blue nicely w/a hot salt process.
Not that you can't get them to rust, then boil & change to blue and card them, ect. They just don't stand up as well as one would expect. They wear very quickly at the edges and high spots when handled.
Not what you'd expect from rust blue properly done.

Sometimes the cold rust process has to be abandon and the quick rust process used. I've used a combination of both on some bbls to get what I want.
Each piece can be so different from the next.

When removing a blued finish by filing or abrasives,,the hot blue will file and polish off with no noticable loading of the file or abrasive paper.
A rust blue finish will load a file right up with a dense red powder (rust) as you try and draw file the tubes out.
It's easier and less time consuming to remove the rust blue with a chemical first,,then do the draw file work.

Even the chemical like common Naval Jelly will take quite few minutes to start to work through a decent but old rust blue finish.
Placed onto a hot blue finish, the blue will begin disappearing in a matter of a few seconds as you brush it on.

In the end I guess that little exersize proves little other than it takes less effort to cut through the hot blue than the rust blue.
Neither is bullet proof and both will eventually wear. They both need attention to keep the surface from rusting.

As with most everything in this business,,there is never only one way to do things to get the desired results.
..and it's the results that count.
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