Flame activated Anodize coloring

While I was heating my flashlight to break the threadlocker I think I overheated it. As a result the Black turned Burnt Sunset. I thought that the Al was turning cherry red but when I pulled the flame away it coalesced into a full even color. I then remembered that aluminum disintegrates instead of glowing like copper. So I just let it cool and found the burnt sunset head to still have the same texture as the black body. I loved it so much I took the rest of the light apart - all o-rings and button - and started flaming all of it. Here are some before and after shots.
This is my Hugsby Firestarter that Ictorana came up with here

So does anyone know how this happened? Is this know to work with HA?

I think it's the black color which is sealed in the HA coating has changed due to the heat.
Aluminiumoxide can withstand pretty high heat.
Anyway, that looks very nice!

odd.. the hugsby light is type II ano,right?

That looks sweet!

Looks very nice. :huh: Would be interesting to compare the results between TypeII-Black and HA.

Unfortunately I'd expect that most lights are made of heat-treated / hardened aluminum so I'd guess that they will be softer / weaker after doing this.

I once left a black anodized light stand in the back of my truck for a week. After sitting in the hot sun for that time, the black turned to a brownish copper color. I recon it's just the breaking down / fading of the dye used in the anodizing process. Using a torch would just amplify / speed this process.

Luckily it turned out cool for you!

Kestrel said:

Unfortunately I'd expect that most lights are made of heat-treated / hardened aluminum so I'd guess that they will be softer / weaker after doing this.

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+1

still looks cool!

Wait till you see what happened to the 2D Black Mag and CMG Infinity.
Just some old beaters I had laying around.
Pics Tomorrow

Here is a partly flamed/heated Spiderfire tailcap. The color in original photo looked orange. I enhanced the colors so it's more like the real color. The heating should be done carefully for even color.

It must be that the heat is changing the anodizing die somehow, but I'm not really sure what reaction is going on. It is black dye, so it should not normally contain any orange dye. The dye is actually trapped inside pores, so I would think that the dye isn't reacting with any foreign compounds; it must be the dye itself changing. If the dye is reacting with something in the air, then that would mean that the anodizing has become unsealed, which I don't think is very likely to happen (since it is sealed by chemical bonds).

Also, weakening the aluminum is not the only issue with heat. Aluminum oxide has a different thermal expansion coefficient than aluminum. This means that the heat will cause the anodizing to expand at a different rate as the aluminum, which can cause cracks in the anodizing. I wouldn't be surprised if heating it with a torch will weaken the anodizing enough for it to simply rub off (especially if oyu heat it for an extended period of time).

nein166 said:

Wait till you see what happened to the 2D Black Mag and CMG Infinity.
Just some old beaters I had laying around.
Pics Tomorrow

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Winx said:

Here is a partly flamed/heated Spiderfire tailcap. The color in original photo looked orange. I enhanced the colors so it's more like the real color. The heating should be done carefully for even color.

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Nice! I wanna incinerate something too! :devil:

Mjolnir said:

It is black dye, so it should not normally contain any orange dye.

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True, but a lot of times even "black" dye can turn various shades of brown/orange.

I happen to have a black mini mag head laying around, I'll go see what sort of damage I can do. Pics soon if there's anything good to show.

By the way Nein, I'm in no way trying to hijack this thread, just adding to the collective knowledge base, hope you don't mind!


*Results* - Sure enough, first the anodizing had a slight reddish glint to the black, next thing i knew, it went deep rootbeer brown and then quickly into a light brown / copper tone. Plus due to what may have been the difference in cooling between the host metal and the anodized outer layer, the surface has a "crazed" appearance that's almost prismatic, but you only see that when viewing the part with a light source that's on the same axis as your vision.

It actually breaks light down into colors. A full spectrum source like the sun shows a rainbow effect, an led light creates just a single color, and it's almost reflective like a weak street sign.

burn away guys! LoL... keep us posted!

I would advise against doing this to a light that you value. It is likely that it will permanently ruin the anodizing. The "crazing" means that the aluminum oxide layer is cracking, which will make it much less durable. it is likely that it will come off fairly easily. Definitely do not do this on an expensive light.

I also find it intriguing that the white lettering remains intact, or nearly so.

Amazing! I'm surprised it turned out having such an even shade of orange / copper.

So I burned the Black CMG Infinity I had on my keychain for years its in bad shape but now its shiny brass in color. The pill was taken out and o-rings removed.

The same prep with the 2D Mag but I started at the tail and worked the flame down slowly. I achieved a smooth fade, but the tail cap was a very different and brighter brass color.

I can definately make out some crazy stress marking in the back end of the maglight, I think this may be from overheating and different coefficient of linear expansion in the Aluminum and Aluminum Oxide like Mjolnir stated. I'll throw the 2D in my car, on the floor to take some abuse this winter.

This can be done on a stove top! i felt odd as i put the battery tube on the burner...but when it turned the dark golden color i knew at that point that i would not have a black light ever again.

tstartrekdude said:

This can be done on a stove top! i felt odd as i put the battery tube on the burner...

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Ever since this thread was started, I've been waiting for someone to post this. I've ben seeing visions of CPFers heating their torches on the gas stove, dropping them when they get too hot, and then setting fire to their kitchens.