doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Opinions on who best replicates case colors

I just lost an explanation of more of how this works after 2 hrs of typing. I'm going hunting, will return with more group theory later.

Here's yet another thread from the past, on CC prep. I'm trying to consolidate info.

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=412401&page=1

I'll post more as I find them.


http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=285456&page=1

http://www.homemodelenginemachinist.com/showthread.php?t=4520

Here's a thread with posts from both Doug(PA24) and Tony Treadwell(Ballistix999). RIP.

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=196529&page=1

I might as well provide this one as well. It's the 30+ page thread from the Marlin forum.

http://marlin-collectors.com/forum/viewtopic.php?f=21&t=3732&hilit=case+coloring

Thanks for taking the time CZ, I'll watch for your update.

I don't know the chemistry behind it, but chances are the iron oxide that's formed to appear as colors is in a stable molecular form, -O3? How much light energy would have to be applied to make that molecule take up an oxygen atom and convert to -O4? I'm asking because you mentioned that light energy and the availability of oxygen were the cause of light degradation of case colors.

If the iron oxide isn't converted, but some crystalline structure that the iron oxide formed is disrupted, what is the O2 oxidizing, and how much energy does that take? I think I've seen it start at lower temps, but there's some mention by pro finishers, in Ken's links, to keep tempering temps at 400*, more will fade colors. Can ambient light add that much energy?

Just asking is all. I believe, subjectively, light does fade case colors, but by how much?

My original treatise focused on plain table salt, so that every reader could have something in hand to look at.
This topic will really get into the weeds, or down the rabbit hole, so I'm going to use the simplest models and visual images I can concoct.
It usually combines 400 and 500 level Chemistry, Mathematics, and Physics, depending on which thing you are looking at. I'm going to stay more between chemistry and physics, and I'll maybe toss in some math references in case there's someone that is more intune with that. This is high nerddom guys, so, I can't do a perfect job on this anymore. And as always, if someone comes along and says it's all crap, I'm OK with that.
This is really just an explanation for why we can rub off colors, and why they can disappear, or morph.

Table salt is NaCl Sodium Chloride. A simple molecule of 1 Sodium atom and 1 chlorine atom. They stick together because Chlorine is electron greedy, and wants an 8th electron in it's outermost orbital shell, and Sodium wants to be rid of it's single outermost electron so it too can find a more stable state. A match made in heaven.

I picked sodium, because it's simple, and, it's chrystalline form is a little cube. Dump out some salt. It's all little cubes, and no matter how finely you grind it, it makes ever smaller little cubes. Little scaled hay bales that neatly stack, with a bit of attraction for each other.

Notice how with the application of energy, salt molecules only cleave along the lines that make the cubes. It doesn't leave us with metallic sodium pieces and clouds of chlorine gas. Thank God! that's because the bonds between salt molecules ie. between those that are right next to each other, are weaker than the internal bonds keeping the NaCl molecule together. They break first.

So, we can establish that there are fault lines in stacks of these crystals, and they are easier to break along than the bonds of the molecules.

You can find spectrographs of salt molecules on the web.
They look like big stacks of hay bales.
Lets add color.
Color is light absorbed by molecules, and that which isn't absorbed, reflects back to us in certain wavelengths, we see as color. So, a banana is yellow, an orange orange, etc.
SO, Where does pink salt, red salt, blue salt come from? Pure NaCl is white. Well, From the addition of impurities. Potassium (K), Magnesium (Mg), Lithium (Li), Cobalt (Co), Sulphur (S) and many others. All absorbing different wavelengths into their frameworks/cages, and reflecting light back that we see as colored.
And, none of these impurities is the same size as the Na atom. So, their molecule formed with Cl is a bit different shaped than the NaCl molecule. In fact, MgCl2 is an Octohedral, linear molecule, with a great big Mg atom in the middle. Try stacking pipes sometime.

So, if you stack the salt hay bales, and some of the bales are a different size and shape, how stable is the stack of bales? They'll still attract somewhat to each other, but, sooner or later the pile will fall over. You could call that seeking a lower energy state. A pile of hay bales after a storm is a more natural state than a precise pre storm pile of mixed shape bales. But also notice, a precisely stacked pile of identical bales can withstand a pretty severe storm without toppling. Storm being addition of energy.

Doctor Mendeleev is groaning right now.

So, I'm pretty sure that we can see that at the molecular level, it isn't a huge stretch to imagine our globules of impure Iron Oxide compounds could be disrupted similarly to our simple salt hay bales that have some weird shaped impurities added.

I'll throw this in for a little support, instead of just 1 state possible, like the Na Sodium atom and it's simple desire to shed it's one measly electron for it to be happy, metallic Iron has 8 different ones possible. It's a very fickle atom. Some days it wants electrons to be happy, other days it wants to shed electrons to be happy. It depends on the relative desirability of the new neighbor, as to what it does.

Because of that, I started with simple salt, because cubes are easier to talk about than piles of dodecahedrons.

Before I move on, imagine big piles of the Dungeons and Dragons dice. We don't make hay bales shaped like them for a reason.

You hit it.

It's entropy.

Kindly post the REDOX equations, in descending order.

Someday, all guns will just be cooled plasma floating forever.

But seriously, carry on. I'm enjoying the discussion.

I know you mentioned more to come, so I'll keep a watch for it. Are you thinking of abrasion resistance, or some reaction kicked off by added energy, light?

If I'm not mistaken, it looks like impurities are the key to what happens?

The thought that comes to mind is that heat temper colors are created by iron oxides, the same oxides as in case colors. The temper colors apparently form by differing light reflection based only on the thickness of the iron oxide layer and not impurities. Again, these are likely identical iron oxides as are present in case colors.

Temper colors are generally thought to be quite a bit less durable, rub off easier, than case colors.

If I'm not mistaken, Doc Gaddy's research showed that the stacked globs of iron oxides, as opposed to the flat sheets of temper color iron oxides, were not caused by impurities that disrupted crystal formation. I think he found that a non reacting inclusion, phosphates?, acted as a temporary form for the layering oxides. But, I think he said it was water soluble and went away. I think that's how the random tipping over hay bales are formed?

Anyway, you're probably right about impurities forming color, because as case colors wear, the color doesn't change. But, on the other hand, someones going to have to come up with a reason why impurities clump together to form areas of distinctly different colors. Wouldn't impurities likely mix and dilute, rather than concentrate and separate?

Sorry, I drifted way off the light as an energy source topic.

There are 110 year old A Grade Fox shotguns that have the most brilliant well preserved case colors any of us have seen. I don't think they were protected from light. I also don't think my 145 year old Westley Richards eight has been specially protected from light, but it is still new. The hidden exterior parts of many double guns have been protected from wear and are "new", but they weren't particularly protected from light. What is the explanation? Light fades case color or light doesn't fade case color?

It is no coincidence that what is in the charcoal and the quench effects the colors. You can carburize steel in pure carbon, and vary the final color exactingly by temp at quench.
I posted that metallurgy class link in the past. Each 50 degree difference, different color blue.

Hint: When a hobbyist is reverse engineering a master's colors, look at that video for reference.
And then there are what are known as polymorphs.
They explain some of Dr Gaddy's observations.
Same chemical formula, same atoms, just stuck together in different forms. And held there at quench by cooling. And they look different. There are thousands of Iron/Oxygen polymorphs. Image a mirror image . That's a simple polymorph.

A poor example might be taffy. Look at all the shapes it can take if you freeze it, but when all is said and done, it's still taffy. That's why you can sample various pieces of case coloring and get Iron, Oxygen, Potassium, Magnesium, in the same approximate ratios. But the scratchings you were testing would still look different.-
These polymorphs may look like a twisted birdcage at quench. And light, when shone upon it, will be absorbed into the wires of the cage, and reflect as other colors. And various impurities can be lodged/captured within the twisted structures.
The wires of the birdcages can be represented mathmatically by Vectors, as they have a strength, and direction. But that's an area of science not needed at the moment.

The wires of the bird cage absorb energy. They resonate. They stretch, pull, bend etc. Their captured impurities introducing additional stresses.
And right about here, we start touching on Quantum mechanics, and what exactly is going on when those molecules absorb energy.

I liken the web of compounds creating the surface colors to the truss work in a large domed stadium or arena. Each connecting link supported by, and tied into each of it's neighbors. FWIW.

Sometimes when I'm out in the weeds like this, I wonder if Oscar ever pondered the same stuff, and kept it to himself, because, well, they'll hospitalize you for less.

So, where are we?

We have stacks of haybales that can be cleaved along planes.
We have weird shaped polymorphs that look different. But are chemically the same.
We have impurities that can be stuck in between the poorly fitting polymorphs, that look different. That we can manipulate.
We have polymorphs described as twisted bird cages, all stuck together like truss work. And probably happily desiring to attain an untwisted state of lower energy.

I guess, now, all we need is a way to manipulate the wires in the bird cages, or the bolts in the trusswork, to our satisfaction. See if we can cut them loose.

Again, if there's a P-Chem guy out there, jump in.

And remember, in practice, no one needs to believe any of this to do great work.

As I recall Oscar Gaddy did a test with samples of color case hardened steel. The samples on the window sill, exposed to the sun were no different in a few years than those hidden away in the dark.

But, "Tell me about the wabbits, George". Are you saying that because light is energy it affects the polymorphs the same way as abrasion? I just cannot make that leap yet. Give me indisputable evidence.

SRH