Stainless vs. Carbon
What is the structural difference between stainless steel and carbon steel? Other than cosmetics, is there a functional difference between these two? How about parkerized and blue finishes? Moreover, what is the functional difference between Gallium, Titanium, and Scandium? Which really is lighter, stronger, more resilient?
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Hi PP,
There is no short answer to your question so here is a summary.
Stainless is a generic name for many types of steel and basically has these components: carbon, manganese, phosphorus, sulfur, silicon, chromium, and nickel. The type of stainless or carbon steel depends upon the percentage of each of the above components. To be a stainless steel it must contain 10.5% chromium.
The chromium is what gives the stainless its corrosion resistance properties. In general, the higher the proportion of chromium, the stronger the corrosion resistance. Nickel is used to strengthen the the chrome oxide layer that forms on the surface of stainless.
Chrome is magnetic (a magnet will stick to it) but the nickel modifies the phsyical structure of the steel and makes it non-magnetic. Therefore, it is the nickel that would make the stainless non-magnetic.
Carbon steel is usually known for it strength and contains a higher propotion of carbon. Many knife blades and high quality tool steel is made from carbon steel. It is the property of carbon that gives stainless its strength like carbon steel. Most stainless is magnetic (a magnet can stick to it).
Whether the stainless is magnetic or not really doesn't have anything to do with the quality of the steel, rather it has to do with the property of the steel for its intended purpose.
Parkerized and blue finishes are just that - they act like a chemical sealant or plating that is applied to the exterior of the gun metal after the steel has been formed and finished. This plating is to protect the firearm from corrosion and wear.
In the case of titanium, it is a metal that can be alloyed with other metals. The advantage to titanium is its strength versus weight and its corrosion resistance. It is as strong (in some aspects) as steel but weighs 45% less. Many light or "ultra light" firearms are made with titanium alloy for a light and strong firearm. Titanium is a good material for firearms but usually makes them slightly more expensive. Powdered titanium metal goes for about $100.00/lb.
Regards,
Heavyiron[8D]
"If I don't see you nomore on this world, I'll meet you on the next one, and don't be late!" - Jimi Hendrix0 -
Jorge,
I think that heavyiron's answer is far better than I could manage for the metals but I will add a bit to the finishing discussion.
Here are some brief descriptions for finishing processes:
Parkerizing:
"...the true process of phosphating is a conversion-coating process wherein the acid actually dissolves some of the metal from the surface and re-deposits it in the form of an insoluble metal salt onto the surface. This "salt" is a combination of iron and phosphate (in the case of iron phosphating), iron, zinc, and phosphate (in the case of zinc phosphating), or iron, manganese, and phosphate (in the case of manganese phosphating). If you leave out the manganese, what you get is iron phosphating, which has the same color as the base metal."
INSTRUCTIONS FOR "HOME-BREW" PARKERIZING:
You need a number of things to do a "home-brew" "Parker-job", but only 4 ingredients.
1. Phosphoric Acid (the active ingredient in Naval Jelly) usually procured at a chemical supply house.
2. Powdered Manganese Dioxide (a very dense and heavy dark gray to black powder) also available at any chemical supply house.
3. Distilled water (I've used tap water, but the distilled stuff gives more consistent results.
4. A biscuit of steel wool (don't use soap pads or Brillo pads!)
I used to do this on the kitchen stove (I wasn't married in those days) in a one gallon Pyrex beaker (these little beasts are expensive, so be careful with them). Metal pots don't work as well (if at all) I understand, but then I never used anything else but Pyrex.
Proceed as follows:
1. Use one whiskey jigger (yeah, this is really scientific, right?) of phosphoric acid added to the water. Remember your high school chemistry, ALWAYS add the acid to the water, and it is best done by pouring it down a glass rod!
2. Use one whiskey jigger of the (powdered) Manganese Dioxide in the solution.
3. Bring the solution to an extremely slooowwww rolling boil .
4. Now add your biscuit of steel wool.
I used wooden sticks placed across the top of the beaker and suspended the parts in the solution using steel or iron "machinist's wire or some such. DON'T use painted coat hangers or any wire with grease on it! You can usually get this stuff from a machine shop or from Brownell's.
The parts should be totally immersed in the solution, being careful that anywhere the wire touches the part won't show on the finished part (usually easy to do - like in the firing pin hole of a bolt). The part(s) to be Parkerized should be totally "de-greased" and sand or bead blasted prior to finishing (depending on the texture you desire on the finished part). Once you have bead blasted the part, you should handle the part with gloves (never greasy hands) and store them wrapped in clean paper towels awaiting the Parker Bath. Any grease on the parts or wire will cause what can only be politely called a variation in color (the parts come out streaked and spotted like a "paint horse").
I usually let the part remain in the solution for a total of 20 minutes (less MAY work, but I was told 20 minutes so that's what I used and it worked marvelously). When you withdraw the part, immediately rinse it in hot running water to get the solution off of it. Use extremely hot water, and the part will dry itself. Let it dry (and get cool enough to touch) on some clean paper towels, spray on some lubricant and viola' you are done!
Rumor control said that if you immersed the freshly rinsed and still hot part in Cosmoline, it would give the sometimes sought after "gray-green" tint to it. I have never tried it. Cosmoline is still available from Brownells if you are adventurous!
The original formula called for iron filings vice steel wool, but since I didn't have any floating around, and didn't want to file on the cast iron stove, I found that the steel wool worked just fine. What you get is a chemical reaction that causes an iron phosphate to form on the metal (steel phosphate I suppose, using steel wool). I have found that the resultant finish is just as durable as the Arsenal finishes and has exactly the same appearance! - an attractive dark gray, almost black. Some say that adding more manganese dioxide causes a darker finish, but I've never tried it, as I was happy with what I got!
We often used this technique when finishing .45s built on early Essex frames that needed a lot of fitting, thus often requiring the removal of offending metal. I used to checker the front straps (also violating the finish in a rather spectacular fashion) and the resultant finish worked great and showed little or no wear even with extensive use - much like the official GI finish. I'm still using a wadcutter gun I performed the magic on back in the `70s and it still looks new.
A couple of cautions:
1. Always be careful of any sort of acid, even such an innocuous acid as phosphoric. I certainly would never deliberately inhale the fumes (although there is no great odor to the process that I could tell, but then I smoke cigars). I started doing this back in the early to mid `70s and still have no "twitch" that I can directly attribute to Parkerizing on the kitchen stove. Just use common sense, WEAR GLOVES AND EYE PROTECTION ANYTIME YOU ARE PLAYING AROUND WITH BOILING SOLUTIONS (with or without acids being involved).
2. Be very careful not to cause any splashes with the boiling solution (of course the same can be said of boiling corn).
3. Prepare your area and your parts before hand, don't try to do this on the spur of the moment.
4. Send your wife to see "Gone With the Wind" or "Titanic" or some other movie that whiles away a number of hours. If you ever want to do this again, make sure the kitchen is spiffy when she returns! In Gloria's case, she would be attaching the parts, but then I'm just lucky in that respect...
5. Once you have allowed the solution to cool, you are DONE! Re-heating it don't cut it, It simply doesn't work (I've tried it on several occasions). Have everything that you want to Parkerize ready to go when you fire up the solution. You can keep Parkerizing as long as the solution is hot, but allowing it to get cold kills it - you've gotta' brew up a new solution and start from scratch.
6. Do not name me in any divorce proceedings!
Good luck!
http://www.jouster.com/articles30m1/parkerizing.html
Parkerizing is a very simple immersion process requiring the solution to be heated to approximately 190-210 degrees and the dipping time can range from 5-45 Minutes or so, depending on the hardness of the metal and the desired thickness of the coating. It is a fast process from start to finish, for example a Colt 1911A1 or similar auto can be dipped, rinsed, coated with preservative oil and reassembled in an hour or so. In fact it is probably the fastest and easiest to apply of all gun finishes used today and any Parkerized Gun is protected from the elements much better than can be attained from blueing.
Parkerizing is much easier to use than bluing and because it is a Matte Finish the parts or items you want to Parkerize do not have to be polished, they can be acid dipped, sanded, bead blasted or sand blasted. In fact a lot of nicks and scratches that would show up on a blued item would not even be seen after Parkerizing.
http://www.parkerizingkits.com/
Parkerizing:
This is a phosphate coating used primarily on steel parts. It provides a thin crystalline film that enhances corrosion resistance and adhesion. The three common types are manganese, zinc and iron. In the firearm world, the most commonly used is manganese which is used as a final finish when appearance isn't much of an issue. Zinc is used when build up is not desirable.
As a final finish, they offer a small amount of surface protection by themselves. What really happens is that they offer a base for holding supplemental coatings such as oil. The real protection comes with the addition of retained oil.
We don't use phosphating as a final finish. Zinc phosphate, however, is a very functional pretreatment before the application of polymer coatings. It provides microcrystalline structure with good "tooth." This process is used in preference to spray primers because of coverage and adhesion qualities.
http://www.trippresearch.com/tech/parkerizing/parkerizing.htm
"Blue finishes" can run a fairly large gamut from the poor process of cold bluing to the premier example of Belgium Slow Rust Bluing.
Cold bluing should be reserved for emergencies or very small, temporary corrections. It is not considered to be worthwhile by most folks interested in a good finish. There is one possible exception but since I haven't used it, I can't comment. Maybe some of the others can help here. http://www.bluewonder.us/BlueWonderGunBlue.html
Hot caustic blue involves the use of sodium hydroxide(caustic soda) in a super saturated solution along with other chemicals in a combination that turns chrome moly steels black. It is actually oxidation or rust as it is commonly known. The operating temperature range is 280 F. to 300 F. This process involves tanks, burners and lots of runnning water of good quality. It is not for the home hobbyist. This caustic soda will burn its way through skin and clothing in short order, producing severe burns.
Nitre bluing involves the use of molten salts to change the color of a metal in a range from a yellow (straw) to a deep, almost iridescent blue. This is a very fast process but it does not yield a sturdy finish. Also, you should keep all forms of water and moisture away from the molten salts unless you really feel the need to see a Mt. St. Helen's eruption. This is the dangerous part of handling molten salts, they don't mix with water at all and the burns are horrific like caustic burns above.
Rust blue is probably the most hansome surface finish available for firearms. For home application, I recommend looking at a Brownells catalog and selecting one of the 2 rust blues that they sell. It is not inexpensive but it saves time and aggrevation for procuring the acids and iron nails used to create the working solution. Angiers book lists out several formulas for rust blue. This is the finish used on double guns, fine or otherwise, as well as high grade rifles for the discerning owner.
http://www.realguns.com/Commentary/comar51.htm
This may be long but it is brief by comparison to what has been written about these processes. There is a lot of information on the internet and in books on the subject. Brownells sells a short booklet that pushes their products but also manages to give a reasonable explanation of some of these processes.
Best of Luck!0
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