What are the different methods for coloring metal?

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Discussion Overview

The discussion revolves around various methods for coloring metal, exploring techniques used in commercial applications, particularly in relation to products like Apple's iPods. Participants discuss both the advantages and processes involved in different coloring methods, including anodizing, powder coating, and corrosion-related techniques.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants inquire about the methods used to color metal, specifically referencing Apple's anodizing process.
  • There is mention of controlled corrosion as a potential commercial technique for painting metal, with some participants questioning its validity.
  • Electrochemical corrosion is proposed as a method to reduce the thickness of sheet metal for aerospace applications.
  • Anodizing is described as a process that creates an oxide layer on aluminum and titanium, which can be dyed for color.
  • Powder coating is discussed as an alternative to anodizing, with a description of the application process involving electrostatic charge and baking.
  • Participants mention the use of patinas and other techniques to colorize metal, suggesting a variety of methods available.
  • One participant humorously notes using Coke and a car battery for anodizing metal.
  • There are references to the use of lead-based paints and specific products like Hammerite for coloring metal.
  • Some participants clarify misconceptions about the materials used in iPods, asserting that they are indeed metal.
  • One participant emphasizes the broad nature of the question, suggesting that the choice of method depends on the desired outcome.

Areas of Agreement / Disagreement

Participants express a range of views on the methods for coloring metal, with no consensus reached on a single best approach. Some methods are agreed upon as common practices, while others remain contested or unclear.

Contextual Notes

Participants mention various techniques without fully resolving the effectiveness or applicability of each method. There are also references to specific products and processes that may require further research for clarity.

Who May Find This Useful

This discussion may be of interest to individuals exploring metal finishing techniques, those involved in manufacturing or design, and hobbyists looking to colorize metal for personal projects.

yameiyakuma
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How do you colour metal?

What are some advantages of corrosion?

What are the methods one can use to stain mental or change the colour of metal as the Apple company does to create the wide range of different beautiful colours that their iPod's come in?
 
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It's ironic you brought up corrosion because when I saw the title of this thread, I instantly thought of how well rust accepted several coats of rust-stop primer, and how well the primer accepted several paints of preferred color as well. I was going to make a joke about it, but is controlled corrosion actually a commercialized technique for painting metal?
 


You can apply electrochemical corrosion to reduce the thickness of sheet metal for airspace applications.

Anodising.
 


Pythagorean said:
is controlled corrosion actually a commercialized technique for painting metal?
I was wondering too if maybe they use some sort of acid like with chroming. Most finished metal though I am pretty sure is coated with something. I'll have to look that up.
 


yes... its used as a commercialized technique for painting metal!
 


yeah, with aluminum, you treat it so that it builds up an oxide layer (essentially ceramic, i think) that is thick and even enough to prevent further corrosion. i think there is just a dye in the chemical solution that becomes impregnated in the oxide layer, but it's been about 10 years since i had to worry with it, so the memory is a bit fuzzy. it's not really a "paint", tho. aluminum anodization is fairly common and you should be able to google a bunch of shops, easily.

if an actual "painting" technique is what you're after, then there's some interesting stuff like epoxy coating (powder coating), but i don't think it's going to look like a metal surface when done, unless maybe clear.
 


I've had various parts anodized and powder coated.

Anodizing is applied using electrolysis whereas with powder coating you electrically charge the part, spray it with a dry powder, then bake it to cure.
 


This might help.
Do some research on cold and hot patina. Various techniques have been invented to colorize metal.
 
  • #10


Maybe this is off topic but I have anodized metal with Coke a Cola and a car battery hahaha
 
  • #11


Then there's alway lead based paints :/
 
  • #12


Hammerite, great stuff.
 
  • #13


yameiyakuma said:
What are the methods one can use to stain mental or change the colour of metal as the Apple company does to create the wide range of different beautiful colours that their iPod's come in?
I don't own an iPod, but I thought they had plastic bodies.
 
  • #15


Well, after some thought, i guess the best answer is...

anyway that you like.
 
  • #16


and naw...i got an ipod right here and this baby is metal!
 
  • #17


yameiyakuma said:
What are some advantages of corrosion?

Corrosion gets rid of that pesky metal you leave on structural members after machining, and it's free.

What are the methods one can use to stain mental or change the colour of metal as the Apple company does to create the wide range of different beautiful colours that their iPod's come in?

Apple uses "anodizing." Certain metals, like titanium or aluminum, that can be passivated (that is, grow a hermetic oxide layer) can have the passive layer impregnated with dye. The final product produces a very robust coating where the atoms have grown in register with the underlying metal, so you get very good adhesion and protection of your base metal, and an attractive finish. Passivation is, from certain manners of thinking, a TYPE of corrosion, which may lead to your above question.
 
  • #18


Paint, Powdercoat, Anodize, Plating (di and tri chromates etc),

really a broad question. What do you want to do?

may i suggest: finishing.com it is a great trouble shooting site.


good luck with whatever it is you're coloring. You can get some real wild powdercoat and anodized stuff out there.
 

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