# Is it possible to do "clear" anodizing?



## Mark_Larson (Jan 14, 2004)

*Is it possible to do \"clear\" anodizing?*

So i've read up on the basic anodizing how-to by Chief_Wiggum, but i'm not clear on one thing - is it possible to skip the dye step and end up with clear anodizing? Ie parts that are anodized (Type II) but not colored?

If so, this would be awesome! Does anodized aluminum conduct electricity? (I'm guessing it will because its Al2O3 right?)


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## FlashlightOCD (Jan 14, 2004)

*Re: Is it possible to do*

I think what you are refering to is Natural HA, take a look in the Sandwich Shoppe for the new PR-T heads, one of them is Natural HA. It appears to be kind of a dull Aluminum color.

Take a look at the head in this picture.


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## Kiessling (Jan 14, 2004)

*Re: Is it possible to do*

I read in another thread which I cannot find right now that this was possible, but something was difficult about it ...
bernhard


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## Mark_Larson (Jan 14, 2004)

*Re: Is it possible to do*

[ QUOTE ]
*FlashlightOCD said:*
I think what you are refering to is Natural HA, take a look in the Sandwich Shoppe for the new PR-T heads, one of them is Natural HA. It appears to be kind of a dull Aluminum color.

Take a look at the head in this picture. 

[/ QUOTE ] Isn't Natural HA what is done with the Arcs and almost everything else? As in Type III, comes out matte gray? I want clear anodizing, that comes out looking shiny silver like raw aluminum - like the Elektrolumens Tri-star and FT-3C.

I want the looks of shiny aluminum, with the protection of anodizing. /ubbthreads/images/graemlins/naughty.gif


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## LightScene (Jan 14, 2004)

*Re: Is it possible to do*

The anodized aluminum that I've tested does not conduct electricity.


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## Mark_Larson (Jan 14, 2004)

*Re: Is it possible to do*

[ QUOTE ]
*LightScene said:*
The anodized aluminum that I've tested does not conduct electricity. 

[/ QUOTE ] Well that would put a biggie-sized wrench in my plans - i was thinking of clear anodize all over because its not possible to do just the outside. And i love the look of shiny aluminum.


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## Negeltu (Jan 14, 2004)

*Re: Is it possible to do*

None of my anodized lights are conductive.


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## tylerdurden (Jan 14, 2004)

*Re: Is it possible to do*

Aren't the "silver" PM6 and X5T clear anodized?


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## Alan Hsu (Jan 15, 2004)

*Re: Is it possible to do*

My question is can we use dye to create a lighter-colored HA III surface, say silver?


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## Icebreak (Jan 15, 2004)

*Re: Is it possible to do*

If you are talking DIY, I believe Chief Wiggum and others have indicated that the power needed for the anodizing and cooling of the mix makes HA III unlikely for DIY.


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## chalo (Jan 15, 2004)

*Re: Is it possible to do*

[ QUOTE ]
*Mark_Larson said:*
[ QUOTE ]
*LightScene said:*
The anodized aluminum that I've tested does not conduct electricity. 

[/ QUOTE ] Well that would put a biggie-sized wrench in my plans - i was thinking of clear anodize all over because its not possible to do just the outside. And i love the look of shiny aluminum. 

[/ QUOTE ]

Clear anodizing is used on almost all consumer products made of aluminum-- without it, the metal would become dull from exposure to oxygen, moisture, and environmental chemicals. A clear anodized surface looks glazed or very subtly grainy compared to a bare polished aluminum surface. 

However, both clear and color anodizing can be "masked" with plugs, wax, or other coatings; or they can be selectively removed after anodizing is complete. Many commercial flashlights have the contact surfaces of mating parts peeled down to bare metal even though the components are anodized inside and out. 

Chalo Colina


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## DSpeck (Jan 16, 2004)

*Re: Is it possible to do*

I was just at a new anodizers yesterday, and they do a "Sanford" process HA, which is pretty clear, and is HA. I saw several examples, and the finish looks like a cloudy, recognizably metal finish. I think that is the closest you can get using HA undyed. If you can find a local anodizer that does the Sanford process of HA, you may be able to get a "clear" HA.

BTW, I was there looking at samples for the next run of the Firefly - it's going to be gorgeous (and NOT black, or "HA natural"). (Sorry for the OT content). /ubbthreads/images/graemlins/grin.gif


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## Rothrandir (Jan 16, 2004)

*Re: Is it possible to do*

can this annodyzer do black?

i *need* to get some pieces black ha3ed! /ubbthreads/images/graemlins/rant.gif


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## cy (Jan 16, 2004)

*Re: Is it possible to do*

Hard Anodizing penetrates the surface of the aluminum, hardening the aluminum. True HA will be grey, or shades of grey. Depending upon how long the part was run.

It's not possible to have a clear hard anodized part. 

I just posted a detailed description in this post: http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB3&Number=444589&page=&view=&sb=5&o=&fpart=2&vc=1


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## DSpeck (Jan 16, 2004)

*Re: Is it possible to do*

Roth, they do a nice black HA3. I saw several samples, and the quality is quite good. Depending on the surface finish you have on the parts, their black HA3 can look as good as the regular type 2 anodizing.

Cy - I thought so too, but the Sanford process HA, whatever that is, is MilSpec (they do parts for the US military), and can be much clearer than the other kinds I've seen. The colours they can do are much more vivid, also.


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## GJW (Jan 16, 2004)

*Re: Is it possible to do*

According to the box sticker, the "silver" SureFires were clear anodized.
I've also got a yo-yo or two that are clear anodized.
I haven't checked whether they're conductive but they have a brilliant platinumy look to them.


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## Icebreak (Jan 16, 2004)

*Re: Is it possible to do*

cy's description in the linked thread was very good. He did anodizing for a living so, though he refuses to except the “expert” moniker his previous demonstrations of expertise on the subject makes his views an outstanding source.

The Sanford process is two-step coloring as described in the linked thread by cy and (seems to me) correctly refereed to in this thread as a *HA* by Dspeck. The Sanford process is complicated by the second step of pigmentation. If the processing isn't done just right it defeats itself to a certain degree. I think it's pretty neat to know that Doug and Peter use this technique for richly colored Type III. My preference would be standard Type III matte black which is dark, charcoal grey. 

What about military specifications?

There are mil specs for clear anodized aluminum for military aircraft. I can't remember what they are. Here are some mil specs that relate to the topic:

There are 3 basics types of anodizing (Type I, II, and III) which are Chromic, Sulfuric and Hard Coat.

CHROMIC ANODIZING Type I MIL-A-8625
SULFURIC ANODIZING Type II MIL-A-8625
HARD ANODIZING Type III MIL-C-5541

Obviously, just because a treatment has a mil spec doesn't mean it is HA III. But mil spec MIL-C-5541 is HA III.

Here is a definition that may help the topic:

*Clear anodized metal:* Metal with a substantially colorless, translucent anodic oxidation coating.

Here are some benchmark terms we might convene upon for naming.

Type I chromic anodizing can be clear or pigmented. It is usually clear.

Type II sulfuric anodizing can be clear or pigmented. It is usually pigmented.

Type III HA is shades of grey all the way to charcoal and can also be pigmented. It cannot be clear.

Sanford Process is Type III HA double dipped pigmented.

From this I would pose that an EL Tri-Star silver anodized is probably Type I clear sealant. It could be Type II. A silver PM6 is probably Type II silver pigmented. An elusive E2E HA III black is probably standard HA III possibly cold cooked with a small amount of black pigment for 45 min. +.

A Firefly is probably Sanford Process Type III HA. 

How does all this address the original question? 

Is it possible to DIY clear anodizing? First, I understand Mark Larson’s logic and it immediately seems possible. I would think Chief_Wiggum probably knows. Maybe that tall dude with large feet knows. I’m sure that some of the MIB guys know. I would also say that if it is possible it should be a Type II sulfuric acid process as Type I chromic acid is bad MOJO. Sulfuric acid is scary enough but chromic acid processing has heavy “forever” components in regard to health and environment concerns.


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## tvodrd (Jan 16, 2004)

*Re: Is it possible to do*

Icebreak,

I have been having aluminum parts anodized for 35+ years. I don't pretend to know much about what happens behind the receiving counter. Most often it has been Type II, Class 2 in various (can be vivid!) colors. Some has been "HA"- Type III, Class 1. It is always grayish, sometimes towards a green/gray. Different alloys vary in color- castings will typically have pits. I know they can pigment it, but it results in a "matt" color. I concur that "HA" cannot be "clear," and I am unaware of "silver" pigments. "HA" will dye black with no problems. DIY Type II home anodizing is very doable- the Chief is having fun (I hope!) (Sulpheric acid is the _best_ drain opener, and fairly environmentally-frendly /ubbthreads/images/graemlins/grin.gif ) I have a flashlight job coming-up where I will try abrasive blasting prior to "HA" to try and achieve a SureFire-class finish.

Larry


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## Icebreak (Jan 16, 2004)

*Re: Is it possible to do*

Larry -

Great answer.

Surely, Type II Class 2 "vivid colors" includes silver? 

I thought the pigmentation of the surface of the metal came from a combination of the anodize and the dye. I thought the colors in Type II were the dye. After re-reading your post a few times it seems I was wrong about this. 

On your next creations:

Abrasive blasting? Can't wait to see the outcome.

Jeff

*** edited after re-reading tvodrd's descriptions ***


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## HunterSon (Jan 16, 2004)

*Re: Is it possible to do*

Check out TNC custon products. Chris sells his lights silver anodized and it looks nice and shiney to me. 
www.tnccustomproducts.com


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## BradN (Jan 16, 2004)

*Re: Is it possible to do*

Want to see some anodizing?

www.maxanodizing.com

I've had paintball guns done by them. WOW. Mine is even in the gallery, the pink pump gun.

enjoy

sorry to hijack the thread but this might help with colors.


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## cy (Jan 18, 2004)

*Re: Is it possible to do*

Hi all,

More clarifications, but first a disclaimer: What I’m describing is what I personally did many years ago. I’m going strictly from memory, current processes may be much different.

Aluminum surfaces oxidize normally and will form a thin anodic film. Anodizing accelerates this natural process and builds up this layer. How thick you build this layer up, if you dye the anodizing and how deep you penetrate the aluminum surface decides what type of anodizing you end up with. 

1. The simplest type of aluminum treatment is to dip the part into a di-chromate solution without anodizing. I believe the insides and threads of an ARC LS are treated this way, and then masked off during remainder of the Anodizing process. This gives the part a light yellow/green tint. This treatment will stop corrosion, but is not very durable. Another reason for this base treatment is anodizing insulates and you don’t want the threads & bottom post to be insulated.

2. Next treatment type is what we use to call di-chromate anodizing. The part is anodized at a relatively low voltage (50-75 amps) for a short time (15-25 minutes) resulting in a thin anodic film. Then the part is dipped into the di-chromate solution for aprox. 5 minutes. I’ve done this process for Aircraft structural parts many times. The final results are a medium Yellow/green anodized part. 

3. Next type is clear anodizing. Typically you would anodize the part very lightly for 15-25 minutes at a low amps (50-75amps). If you anodize the part any longer then the film builds up and starts form a light haze. 

4. Next type is color anodizing. Most customers would want deep rich colors. To achieve this you would need to build up the anodic layer by extending the time, but leaving the amps low. If an anodized aluminum part looks bright and colorful, it usually has a very thin anodic film. Thicker films dull the surface tint. Shortly after anodizing and rinsing off the acid, you would immediately dip the part into a vat of dye for aprox. 3-5 minutes or until the part reaches the desired tint.

5. Next type is hard anodizing. True hard anodizing results by subjecting the part to high amps (125-175amps) for a much longer time. (1 hour +). This process rapidly accelerates the oxidation process at an extremely high rate. It almost looks like the part is burning in the sulfuric acid, there is so much activity. This is why hard anodizing comes out shades of grey. 

This high activity is why penetration occurs below the surface as well on top. The structure of the part physically changes, resulting a very durable part. Hard anodizing can reach a Rockwell of 60-70. 

Still with me? I hope this helps to clarify what takes place when you anodize. 

Thanks for putting up with this detailed description,

CY


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## tvodrd (Jan 18, 2004)

*Re: Is it possible to do*

cy,

Thank you very much!

Larry


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## Icebreak (Jan 19, 2004)

*Re: Is it possible to do*

Yes, thank you, cy.

and thank you Larry.


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## Mark_Larson (Jan 19, 2004)

*Re: Is it possible to do*

This thread just made it into my bookmarks because of cy's post. We'd love to have you around, cy. Knowledge is always appreciated.


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## Jarhead (Jan 19, 2004)

*Re: Is it possible to do*

There is a very thick hard black anodizing that is really hard to scratch, much tougher than the stuff I've seen on flashlights, anyone know what it is called? No, it ain't no powder coat.


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## AilSnail (Jan 21, 2004)

*Re: Is it possible to do*

what happens if you keep on anodizing for a long time and with higher currents than type III?


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## Chief_Wiggum (Jan 21, 2004)

*Re: Is it possible to do*

At a certain point, the layer of alumimum oxide reaches is peak thickness and any further anodizing simply degrades the layer. Too much current and you can actually "burn" the part. 

Just to confirm, all anodized parts will no longer be conductive.


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