# For those of you that tried DIY Anodizing



## bbgobie (Jan 2, 2009)

How does it hold up?
Is it worth it?

I've seen some great pics here, but am wondering how it wears compared to HAIII?


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## LukeA (Jan 2, 2009)

Hard anodizing will be more durable because it's nearly the same process as home anodizing, but unlike home anodizing there are controls on the process that optimize it for producing a thick layer of oxide. These controls aren't present in a home anodizing scenario, and so the oxide layer you could build at home would be thinner and therefore less durable. 

For producing durable coatings at home you may consider Duracoat, KG Gun Kote, or Cerakote. (Gun Kote and Cerakote bake on).


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## gav6280 (Jan 2, 2009)

Your opening up a whole can of worms here.......

Obtaining Type-III thickness at home is the easy part. Type-III thickness is defined as any thickness greater than 1mil (25.4 microns). Most places that improperly say that their product is Hard Coat or Mil-Spec anodized only anodize only anodize to a thickness of 26 - 30 microns (1.01 - 1.2 mils). This is not true Type-III, but is in fact just a thick Type-II coating (Type-II.5) 

To get true Type-III anodizing, besides the thickness requirement previously mentioned, it also has to contain a minimum cell density. The anodizing cells are much smaller in Type-III when compared to the Type-II cells. This means that there are more cells per sq/cm in Type-III. Since the cells are smaller, more can fit within a given area. True Type-III also requires chilled acid baths and some very expensive measuring equipment...

An easy way to tell, which is almost always a good rule of thumb, is that if the anodizing has been dyed, it is Type-II. Type-III is difficult to dye, as the cells are smaller and the dye doesn't penetrate these smaller cells. If the color is gray, ranging from med to dark gray, it is probably a real Type-III coating. Type-III anodizing has a greyish color to it. The thicker the coating, the darker the gray is, until it reaches almost black. This is why they call it Hard Coat or Mil-Spec, rather than using the more precise Type-III classification. 

If you've ever seen Calphalon Hard Anodized cookware, you'll see that it is a dark grayish-black color this is true Type-III andozing. If the color is anything other than gray or grayish black, it isn't Type-III.

Manufacturers know that most people can't tell the difference. The only way to determine if a coating is truely Type-III is to be aware of the color limitations of Type-III or to chemically dissolve the aluminum, leaving only the aluminum oxide, which is then weighed to determine the density. A rather expensive, time consuming and destructive process. 

Now, if you expect to dye your anodizing then stick with the Type-II coating, but grow it as thick as you want. I've been able to grow anodized layers over 3 mils thick (77 microns). The only downside using to the process is that the time required. 

If you were to ask me what the maximum thickness you could grow, I'd recommend you stay in the 2.0/2.5 mil range. If you are feeling brave, you could go thicker, but there is a disadvantage. As the coating gets thicker, it is more likely to be susceptible to cell damage. As the cells get longer, impacts to the surface can cause the cells to snap, producing a white residue. The thicker the coating, the easier it is to damage the cells. This is especially true on part edges. Since anodizing only grows at 90 degree angles to the aluminum surface, it is easy to strike the edge and break off the anodized cells.

If you absolutely require Type-III, (remember, you will have to live with the gray-blackish color as you probably won't be able to successfully dye it), it can be done. Bit youd be bonkers to try it at home it's dangerous and massively expensive to setup.

I am currently doing type II matt black at 1 mil.

I think you had better head on over to the Caswell forum

If your going to do the job properly yourself then you are going to need to invest some time and money in it, but then you could offer your services to everyone else here and make a few bucks....


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## bbgobie (Jan 3, 2009)

Hi Gav,

I'm pretty sure I read that exact post somewhere.

I guess I wasn't too clear. Reading around I'm leaning towards drying type II anodizing. And I know some people on here have tried it like you.

I was just wondering is the finish rubbing off, is it fairly durable enough for every day use etc.

The reference to HAIII was just wondering if someone who's tried it thinks the home anodizing is at least somewhat durable vs the real stuff.

In fact I kinda like the idea of being able to anodize different colours vs just the dark greys-blacks of HAIII.


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## bbgobie (Jan 3, 2009)

Geez Luke,
You've sent me off on a whole night of reading!!!
Interesting stuff, never really been to gun sites before.

Didn't see too much info about how it holds up. But seems the Gun Kote and Ceracote would hold up as well as a DIY Anodizing.

And I think application would allow more options. Very tempting to try out!!
Thanks!


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## diyanodizing (Jan 7, 2009)

Type III anodizing usually needs a large chiller to lower the anodizing temperature to aero degree C. The lower the temperature, the harder the anodic coating. You also need a big power rectifier as well. As the thickness increases, the required power to biuld up the thickness increases as well.

The color of type III anodizing depends on the alloy type. 6xxx alloys give dark gray color. Some alloys give a dull golden yellowish color. Some black dyes are suitable for coloring type III anodizing coating while most of them are only good for type II. You need to select them with care.


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## gav6280 (Jan 7, 2009)

I think you would be better off paying to have someone else do type 2 for you unless you are going to be doing a lot lot of it? Then in that case invest in the equipment, time and knowledge.

Reading through the Caswell forum should gibe you a good start..


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