Wanna see Galvanic Corrosion?

[Zebo]

two years old block in a 24/7 box Link

I've been warning people not to mix annodized aluminum and copper due to galvanic corrosion - the best blocks are either all copper like MCW 6000/6002, Delrin/Copper or Acetal/copper combo. Plastics have thier own problem though- thermal cycling - which will crack overtime thus the former two options are best. Good luck.

 

[zagood]

Dude, learn to use a coaster. That table is thrashed.

-z

 

[Zebo]

Dude who cares - it's in my workshop.

 

[Zap]

LOL, and here I was expecting to see a pic of Galvanized Yankee with a sunburn. :laugh:

 

[GalvanizedYankee]

Originally posted by: Zap
LOL, and here I was expecting to see a pic of Galvanized Yankee with a sunburn. :laugh:

Zap, I'm so white that I can't tan Really! My corrosion is lots of gray hair.

Zebo, was the coolent ever changed in the two year period? Do you ever check the coolent's ph?
Like with litmus(sp) paper.

The anodizing most of us see is decorative in nature. It's purpose is to reduce scuff marks, stop atmospheric corrosion and hold color. What it is, is a very thin porous layer of glass.
Industrial anodizing is not that more expensive a process and can be up to .003"thick. Decorative is .0005"thick.
The point is, if this stuff was industrial anodized, it would be inert.


...Galvanized=A self healing zinc plating used on steel and iron for protecting the base metal from corrosion.

 

[Greenman]

To be honest, that block looks fine to me. In the plumbing around my part of the world water quality is not that good, and most copper plumbing shows minor discoloration/deposits. I'd say that block has at least 5 more years of use in it.

 

[Howard]

Originally posted by: GalvanizedYankee

Originally posted by: Zap
LOL, and here I was expecting to see a pic of Galvanized Yankee with a sunburn. :laugh:

Zap, I'm so white that I can't tan Really! My corrosion is lots of gray hair.

Zebo, was the coolent ever changed in the two year period? Do you ever check the coolent's ph?
Like with litmus(sp) paper.

The anodizing most of us see is decorative in nature. It's purpose is to reduce scuff marks, stop atmospheric corrosion and hold color. What it is, is a very thin porous layer of glass.
Industrial anodizing is not that more expensive a process and can be up to .003"thick. Decorative is .0005"thick.
The point is, if this stuff was industrial anodized, it would be inert.


...Galvanized=A self healing zinc plating used on steel and iron for protecting the base metal from corrosion.

I think it's a ceramic, not a glass.

 

[Zap]

Originally posted by: GalvanizedYankee

Originally posted by: Zap
LOL, and here I was expecting to see a pic of Galvanized Yankee with a sunburn. :laugh:

Zap, I'm so white that I can't tan Really!

That's exactly it, a sunburn. Sorry for my amusement at your expense - if you were here you'd be amused at my expense because when I thought of it I was giggling like a little girl with a secret. Picture that and we'd be even.

On second thought, don't picture that.

 

[GalvanizedYankee]

Your thinking on this is wrong Howard. I make a real effort not to pull comments out of my...You know. Plz do like wise.
Some of the common elements alloyed with aluminum include copper, manganese, *silicon*, magnesium and zinc.

When aluminum is anodized the process causes a deplating action to take place leaving the *silicon* on the surface. This is more closly related to glass rather than ceramic, by a long shot This glass, when produced by *hard*anodizing is very thick and is an insulator of heat and electricity.
If the aluminum being anodized has a high concentration of any of the above alloying elements, aside from silicon, the part will be removed from the solution, cleaned of the alloy's oxide, then reintroduced to the solution.

For an explaination in layman's terms of the anodizing process look around this link. Be sure to read the anodizing forums at this site.
At the very least scroll down to mid-page and look at the micro-pic of the silicon structure.

http://www.caswellplating.com/kits/aluminum.htm


...Galvanized

 

[Howard]

http://en.wikipedia.org/wiki/Anodized_aluminum

Says it's aluminum oxide grown on the surface, which I thought was a ceramic and not a glass.

 

[GalvanizedYankee]

Howard, it's silicon and the deplating process leaves silica on the surface.
Have you ever heard of silica sand?? MMmm.. Glass is made from silica sand.

Read... http://www.webelements.com/webelements/elements/text/Si/key.html

You make a point of looking for fly poop in the pepper, you're a nit-picker dude.
In the future I won't respond to your posts or PMs.


...Galvanized

 

[Howard]

Howard, it's silicon and the deplating process leaves silica on the surface.

I have never heard anything like this. Your first link didn't contradict what I'd thought either. A Ctrl-F for "silicon" leads me to something called Aluminum De-Oxidizer & De-Smut which removes unwanted substances from the to-be-anodized surface such as copper, silicon and magnesium.

I didn't find anything relevant to anodizing in that article you just linked.

This link says:

An oxide film can be grown on certain metals ? aluminum, niobium, tantalum, titanium, tungsten, zirconium ? by an electrochemical process called anodizing.

From the horse's mouth:

It is an electrochemical process that thickens and toughens the naturally occurring protective oxide.

 

[Howard]

Come on, you can't tell me I'm pulling comments out of my ass and then not back up your claims.