wildenout
Member
I have seen some youtube videos on how to do it, I know the chemicals and how it all works. But I want to know what advantages bluing has? Does it keep rust at bay? Does it shield from wear? Enlighten me.
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Teach me about Bluing
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John Frederick Bell
Member
Hot bluing is faster, but doesn't stick as well and requires a fair layout of cash and equipment. It also involves strong caustic salts, so it's not something I'd experiment with unless I had adult supervision. It also needs to be watched for the duration of the process. Properly set up, it can be completed in a couple of hours.
Rust bluing is (generally) slower but holds up better. It can be set up on a fairly small scale and would be comparatively cheap next to hot bluing, but the workpiece needs to be carded with steel wool after every coat, which isn't bad if you're doing something like a Remington 870 but can become frustrating if your piece has any complex shapes or hard to reach places. You'll need a hot-box for the process. On the upside, you can set it cooking and walk away for a few hours. You'll also need multiple coats to get a decent finish. Expect to be at it for a few days.
Cold blue is ****. Birchwood Casey is the worst offender, but in my experience so far most 'quick fix' finishes are a good way to convert pocket money into frustration. Blue Wonder seems to be the best of the lot but...still a form of cold blue. It also won't fool anybody as a professional finish.
Whatever you do, metal prep is king.
Relative to other finishes, the major advantage of bluing is that it's actually fairly simple to do and relatively cheap compared to other processes. Word of mouth says that the most durable finish is paint over parkerizing. Parkerizing will work like a charm provided it's properly treated. Plating would likely be the most airtight of finishes, but it's expensive and requires all manner of nasty chemicals, and it's uncommon to find a gunsmith that offers it as a service.
If you mean to try any of this yourself, practice on scrap first.
Rust bluing is (generally) slower but holds up better. It can be set up on a fairly small scale and would be comparatively cheap next to hot bluing, but the workpiece needs to be carded with steel wool after every coat, which isn't bad if you're doing something like a Remington 870 but can become frustrating if your piece has any complex shapes or hard to reach places. You'll need a hot-box for the process. On the upside, you can set it cooking and walk away for a few hours. You'll also need multiple coats to get a decent finish. Expect to be at it for a few days.
Cold blue is ****. Birchwood Casey is the worst offender, but in my experience so far most 'quick fix' finishes are a good way to convert pocket money into frustration. Blue Wonder seems to be the best of the lot but...still a form of cold blue. It also won't fool anybody as a professional finish.
Whatever you do, metal prep is king.
Relative to other finishes, the major advantage of bluing is that it's actually fairly simple to do and relatively cheap compared to other processes. Word of mouth says that the most durable finish is paint over parkerizing. Parkerizing will work like a charm provided it's properly treated. Plating would likely be the most airtight of finishes, but it's expensive and requires all manner of nasty chemicals, and it's uncommon to find a gunsmith that offers it as a service.
If you mean to try any of this yourself, practice on scrap first.
Bluing is an Oxide coating on the steel surface. It happens to be the black form of the oxide instead of the red oxide .
By itself bluing in most any form does offer some resistance to further rusting (oxidation). But it also is a good surface to hold protective coatings (oil, wax, grease, ect) to better protect the surface.
I'm no chemist for sure. One form is ferric oxide I think,,the other ferris oxide. Rust blue is the simple conversion of the red oxide to the black oxide.
Different shades of the black to blue color come about with slightly different chemical soln's used to produce the simple rust coating to start with.
Caustic Blue (hot salt blue) does the conversion in one step at about 310F in a water soln. It's still an iron oxide finish, just obtained in a different manner. The chemical salts and ingrediants used in the bluing salts can differ and therefore offer different shades of blue/black.
The steel type being blued as well as the manner in which they are done, polish and about every variable imaginable can effect the final look.
Nitre Blue another oxide finish @ 600f to 850F done in molten chemical salts to oxidize and form the thin layer of color. No free oxygen in the air is involved as the parts are immersed in the stuff. PotassiumNitrate usually used, though Sodium Nitrate and even Ammonium Nitrate will work.
There's many ways to achieve a blued surface on steel, but they all involve getting a smooth even layer or built up layers of oxide to occur.
By itself bluing in most any form does offer some resistance to further rusting (oxidation). But it also is a good surface to hold protective coatings (oil, wax, grease, ect) to better protect the surface.
I'm no chemist for sure. One form is ferric oxide I think,,the other ferris oxide. Rust blue is the simple conversion of the red oxide to the black oxide.
Different shades of the black to blue color come about with slightly different chemical soln's used to produce the simple rust coating to start with.
Caustic Blue (hot salt blue) does the conversion in one step at about 310F in a water soln. It's still an iron oxide finish, just obtained in a different manner. The chemical salts and ingrediants used in the bluing salts can differ and therefore offer different shades of blue/black.
The steel type being blued as well as the manner in which they are done, polish and about every variable imaginable can effect the final look.
Nitre Blue another oxide finish @ 600f to 850F done in molten chemical salts to oxidize and form the thin layer of color. No free oxygen in the air is involved as the parts are immersed in the stuff. PotassiumNitrate usually used, though Sodium Nitrate and even Ammonium Nitrate will work.
There's many ways to achieve a blued surface on steel, but they all involve getting a smooth even layer or built up layers of oxide to occur.
Diamondtreo
US Veteran
Slow rust bluing done properly gives an incredibly tough and beautiful finish. Its the only way to do an old double barreled shotgun with lead-soldered rib & barrels (hot blue will dissolve the solder) I learned that the most important step in the process is the prep work. The surfaces must be absolutely clean - no matter how shiny or dull. Any fingerprints will show thru so care must be taken to wear clean cotton gloves when handling at all times after starting the process. The first time you see a piece of work that you have spent hours polishing come out of the hot box, you will be shocked to find rust and nasty looking spots all over the surface - these will come out with carding on a #0000 steel wool wheel. 3 or 4 more cycles thru the chemical application, hot box & carding wheel you will begin to see the deep blue that no other process can duplicate. I believe the surface actually grows 0.0002" 0r 0.0003". For a home gunsmith, its the only way to go in my opinion, as there is no need to set up hot tanks for the chemicals nor do you have gallons of caustic to tend with. A hot box is just a long box set up vertically that you can suspend the barrel in (without touching anything) while a pot of boiling water provides the steam at the bottom of the box. The bluing chemical is swabbed on the surface & steam condenses on the cold metal in the box. A couple of hours in the box, then let it sit for a day, card & repeat process.
A few years ago I had Doug Turnbull refinish a bolt action rifle for me. He rust blued the barrel and charcoal blued the bolt and bottom metal. I consider the price fair and the work is stunning, nothing of that quality has come off a production line in many years if ever.
You should expect a lot of practice time before trying for a quality finished product.
You should expect a lot of practice time before trying for a quality finished product.
OP
wildenout
Member
Not thinking of trying it myself, there is a guy in Morgan who does amazing work I hear. Just wanted to know what benefits it has really?
John Frederick Bell
Member
Bluing will prevent rust, just not as well as some other finishes.
If you want it extra-durable (think 'duck gun') consider something like duracoating, possibly over parkerizing as mentioned. If you want something that'll look good while providing moderate amounts of protection to the steel bluing is likely good enough.
If you want it extra-durable (think 'duck gun') consider something like duracoating, possibly over parkerizing as mentioned. If you want something that'll look good while providing moderate amounts of protection to the steel bluing is likely good enough.
