Anodizing on flashlights. How can you tell a difference?

Ok, so I’ve been doing some reading on anodization. It seems there are sub levels, even within HAIII, HA II, etc. Then there’s also those who can tell the difference between HAII and HAIII, even if the manufacturers specs say something different. My question is, how does one tell the physical difference and feel between II and III- based up touch and look?

Well HIII is more resistant to scratch. It sticks better on aluminium.

Cheaper anodization looks cheap with shiny spray like black colour while HIII looks like premium black matte finish.

I’m not able to answer the question about how to visually ID them from one and other but there is no such thing as HA-II, anodizing is either type 1, type 2 or HA (aka hard anodizing, HA-III, “type 3”). if it says HA-II its NOT hard anodizing at all.

Edit: as a general guideline type II is usually more glossy looking and thinner (showing machining marks threw it more) where HA / type III is thicker, will look more evenly applied and is [usually] less glossy. It also looks more like a true coating as opposed to just a coloring/dying of the metal.

Anodizing isn’t a coating at all, but an acid bath with voltage applied to make the acid agitated and “cling” to the surface. A dye in the water/acid solution is what makes for the colors. So it’s not a coating at all, unless HAIII is not traditional anodizing.

Anodizing is considered a coating. The official U.S. Military term for anodizing, in fact, is "ANODIC COATINGS FOR ALUMINUM AND ALUMINUM ALLOYS" (As defined by MIL-A-8625)

Anodizing simply increases the thickness of the natural oxide layer that forms on Aluminum. The acid doesn't "cling" to anything. The dye is applied after anodizing is complete, but before sealing. Dyed (colored) Anodic Coatings are considered to be of "Class 2", while un-dyed natural color coatings are "Class 1".

Visually, it is near impossible to tell Type I, II and III apart. The significant difference is coating thickness, and that isn't something you can see. Type II coatings are between 0.00007 and 0.001 inches in thickness, whereas Type II coatings are between 0.0005 and 0.0045 inches in thickness.

For more info: MIL-A-8625 Specification

PPtk

I used to think so too. But then I got a SF L2 with type II ano, and it looked as nice and matte as a lot of type III lights that I have, so I can’t really say that anymore. Now, I would say that I could not tell the difference between type II and III just by looking at it.

Correct. You can tell the difference between crap anodizing and good anodizing by looking at it (for the most part), but you can not tell the type.

You can torch it… if it turns orange relatively quickly, it’s type II, and if it doesn’t budge even after a few minutes, it’s HA-III. :smiley:

I wouldn't consider that a definitive test either. Whether or not it changes color with heat will have more to do with the type of dye the anodizer used then it will the Type classification.

Haha, I see. I guess no lights would have to be baked to determine this. :smiley:

Is it simply the thickness that determines the type of anodizing?

However, the process does change between the two.

Source: Anodizing - Wikipedia

There are a lot of things that determine the type. Thickness, Weight, Process, Type of Acid, Rate of Growth, Current Density, Bath Temperature. The thickness is, however, one of the few observable/measurable qualities, and as such, is usually the confirming test for Type III.

Interesting, thanks.

I guess the only realistic way of measuring would be through experience.

For example, my grey SF L2N I think has type II anodizing because I already can see some rubbing off, although it’s only been on my desk.

Anodize of any type should not "rub off" very easily. You have to remove the aluminum oxide in order to remove the anodize - which is amazingly difficult to do.

Yeah, I meant to say that I’m seeing some patches of metal on the edges of the light.

Here’s a shot:

Interesting.. didnt know all that.

Whenever I see a light that doesn`t look like good quality anodizing, I usually just called it HA II (though now I now that it doesnt exist).

For me it was just guessing.. I thought there was something like: 1=paint, 2=shiny paint like substance 3=thick layer

but I stand corrected..

What do you think could cause an anodized coating to fade with only exposure to skin oils and a couple showers? I have one which has lost quite a bit of its color (click for bigger versions):


This shade of turquoise is a relatively subtle color though, so look what happens if I change its hue by 60 degrees to show how the same fading would look in blue: (all I changed was hue, nothing else)


Was this even anodized at all? Could it have been anodized and dyed but not sealed? Any other ideas what would explain this?

Seems like this is a complex issue. Pretty interesting discussion so far though.

Does this mean we can have white coloured anodized type 2 lights?
If this is possible, I want to request that every light from now on is white anodizing.

Anodizing dyes are technically not opaque - they are translucent. Because of this, white is pretty much impossible - it will always be tinted toward the color of the base material - in this case, grey.

PPtk

knee jerk, totally non expert, probably wrong first thought:

paint