new cantle into old cantle

**turpin** · 18th April 10, 11:07 AM

I definitely like the brass better than what was covering it, Joe. Even before I read Tyger Forge's post I was thinking "bury it in a bog". I would do as Tyger suggests - if you have a nice marsh handy. If not, how about a bucket of mud with a bit of sulfur mixed in - or sulfate?

I'm not a chemist.

**piperdbh** · 18th April 10, 11:33 AM

That's pretty. You're about to turn me into a cantle-liker.

**tyger** · 18th April 10, 11:53 AM

Originally Posted by turpin

I definitely like the brass better than what was covering it, Joe. Even before I read Tyger Forge's post I was thinking "bury it in a bog". I would do as Tyger suggests - if you have a nice marsh handy. If not, how about a bucket of mud with a bit of sulfur mixed in - or sulfate?

I'm not a chemist.

Right on. The bucket of mud (if it is good mud, and by that I mean swamp/estuary mud) will contain sulfur; however, if you add some more sulfur that will be even better. Just don't add a lot of sulfuric acid and get the pH down to where you wind up etching the metal. Well, you can go ahead and do that, but you will eat away portions of the alloy, thus weakening it, and I don't think you really want to do that, especially at the hinge.

I find the chemistry of metal sulfate formation fascinating. Actually, most metals are very reactive, and exploration of this dynamic is what I find most interesting about the reactivities of copper and brass, in particular. It is this reactivity that gives metal its warmth, the color range that deepens and gains complexity with time, much like wine will do. You can't get that reaction from either chrome or stainless steel, and pewter is dull by comparison!

Back to Turpin's sulfur: in the presence of oxygen (don't bury the brass too deep- it gets anaerobic down there), the sulfate ion is a polyatomic anion (you have seen the empirical formula SO2 and SO4), and in the oxidative state, conjugated with it's hydrogen base, it yields H2SO4: sulfuric acid.

**piperdbh** · 18th April 10, 11:56 AM

What's the intention of all this chemistry? Will it change the color of the cantle, or eat off the rest of the chrome, or what? As Turpin said, "I'm not a chemist."

**tyger** · 18th April 10, 01:01 PM

Originally Posted by piperdbh

What's the intention of all this chemistry? Will it change the color of the cantle YES, or eat off the rest of the chrome NOT LIKELY, or what? As Turpin said, "I'm not a chemist."

I am not a chemist either. Although I must admit, if I had taken just one more chemistry course I would have graduated with a double major. When I was a kid, my dad told me: "Life is chemistry, so study your chemistry." And he was quite correct. Knowing the chemistry of what is happening around me has really made me more fully aware of life as I experience it.

The "intent" of chemistry- the purpose if you will- is, both in the short term as well as in the long term, all of life. When it comes to metal, many people are surprised to find that metals are dynamic. Metals are not alive, of course; however, metals stretch, bend, vibrate ('sing'), and color.

In the present case, the description of just one fundamental chemical reaction that will endure in Joe's cantle paints a picture: an illustration why and how a reactive metal undergoes natural development of color. All color development is chemistry.

Not all metals undergo dynamic coloration very well, but brass is one metal that does, and we really appreciate that charactistic. Brass color dynamicism is one reason why so many of us are so fond of brass as a metal of ornamentation.

One can delay or inhibit the chemistry of color development by putting the metal in a zip-lock baggie, coating it with wax or oil, or by coating it with polyurethane, laquer, and the like. All these approaches function through deprivation of oxygen. Therefore, SO2 and SO4 don't form, metal suflides don't form, and color change does not occur!

One can also promote the chemistry of color development. Color change will happen in your sock drawer, but it will happen much faster in well-oxygenated sulfur-bearing substrates such as mud.

And if you happen to be one of the people who have high levels of sulfur-containing amino acids on your skin and in your perspiration, then your metals will color faster, and to different hues, than people whose biofilms are lacking.

It is a colorful world. I like color in metal.

**piperdbh** · 18th April 10, 05:01 PM

Originally Posted by tyger

One can also promote the chemistry of color development. Color change will happen in your sock drawer, but it will happen much faster in well-oxygenated sulfur-bearing substrates such as mud.

That's what I'm wondering. What color change will the sulfur cause? Will the metal get redder or browner or splotchy or dark or light or what? I'm really interested to see what will happen with this cantle, and I hope Joe finds a nice, swampy place to carry out this experiment, like this one:

**tyger** · 19th April 10, 04:50 AM

Better the frog than the bull!

These rascals are plentiful around the Forge, and one really does need to avoid getting lulled into a sense of otherwise.

The color change in Joe's cantle will be a shade of brown. Many factors influence this. I would say that the primary factor will be the nature of his brass, in particular what alloy of brass it is. Multiple secondary factors will contribute.

Alloys with higher copper:zinc will color to deeper shades than will low copper content alloys.

I don't know what alloy Joe's cantle is made of; however, I would guess that it is somewhere around 70:30 as this content is sufficiently malleable without being overly brittle, or exceedingly soft. Alloy 260 (70:30) is known as cartridge brass.

alloy 220 is 90:10
alloy 230 is 85:15
alloy 260 is 70:30
alloy 280 is 60:40