Anodizing Titanium

[McGizmo]

Hi guys,
I don't offer any of my stuff anodized but I have had a number of questions through the years about anodizing titanium and I have been meaning to take a quick video demonstrating how one might color their light or other titanium part. I just built a Ti UV light for myself because I let one of you talk me out of my UV PD. I wanted to make this light obviously different than the many white LED lights that are always laying around and I have used anodizing on some other lights to identify them as something other than "white".

In the video, I also anodized a Ti-20 clip. The items seen in the video are these:



I uploaded the video to YouTube, HERE.

This thread can go anywhere you guys want it to including down into the dregs of ignored CPF threads.

I would add that I think the clear oxide film of titanium along with the other refractive metals is fascinating in itself and how you perceive color by virtue of light waves interfering with each other and not due to the absorption of some of the spectrum and reflection of the balance.

I consider anodized titanium for the most part to be a cosmetic feature and unless the anodized surface is reasonably protected or recessed, the film can and will abrade over time and show this wear. On the other hand, there are some situations where having the option of coloring a part does give you means of identification, beyond cosmetics.

In the video, I touched on the point that when you anodize titanium, you don't want any other metal in the bath and part of the electric circuit. If there is another metal. It typically just bubbles away in the bath in that area and you don't get a good film growth on the Ti surface itself. I have used this feature in the past to confirm the claims of some items I bought which were stated to be "all" titanium. In many cases, the claims were false. It's probably silly but for me, there is a certain pride in purity in the fact that I can take one of my titanium lights, as is and even turned on, and throw it in an anodize bath and have it change color uniformly in all exposed surfaces. If you take the light apart, you can see where the seals sealed and there is no anodize color beyond.

[Drywolf]

That was easy! I'll have to try it myself.

[McGizmo]

That was easy! I'll have to try it myself.

I should point out that you don't want anything but Ti anywhere in the bath and that includes your anode and cathode leads to the part being colored. In my demonstration, I have a platinumized titanium cathode rack inserted in the beaker but a strip of titanium will work as well. The clamp and tweezers I used are both titanium.

I got the recipie for the ammonium sulfate some where, probably close to 20 years ago and found some at the local chemical supply house. I guess it is a common fertilizer and available from nurseries as well perhaps. There are other solutions that will work as well and I have heard of some folks using Coke. It worked in a simple test I once did on a reported to be titanium rudder shaft as I mentioned on the video.

[London Lad]

Cool.

I am amazed at how quickly it anodized.
How resilient is the finish ?

[Kiessling]

WOW !
I thought it would take much longer and some really elaborated techie stuff, like Dr. Zarkov's lab or something like that.

Thanx for sharing !

bernie


P.S.: I gave my wife a pink anodized ti light (La Petite Killer) and it lost its finish in a few weeks on the keychain almost completely except in the recessed areas. Beautiful, too, but not what I intended.

[beach honda]

too cool!

That's soooooo Mr. Wizard style!

LOL! Don Mcleish = Don Herbert ???????

[McGizmo]

WOW !
....I gave my wife a pink anodized ti light (La Petite Killer) and it lost its finish in a few weeks on the keychain almost completely except in the recessed areas. Beautiful, too, but not what I intended.

Yeah,
The oxide film is reasonably hard but it is really thin!! I think the best applications, cosmetic wise, are when the colored surfaces are below the typical contact surfaces. I have some wind chimes that I anodized many years ago and they still look like they did on day one but then they are not subject to any real contact beyond the elements which can't effect the surface (sand and hail storms not included).

It is fun to play with because you basically get instant color. If you zap a part at say 40 volts and get a green/ gold color, that color will hold provided you don't subject the part to higher voltage. You could then unmask or cut through the anodize and hit the part at a lower voltage and get a new color anywhere the 40 volt oxide layer was not present. Variations in the surface texture will look different from each other even if anodized at the same voltage. The transition from bead blasted to polished, for instance.

Maybe some of the chemists can chime in here on what is actually happening as the oxide layer is formed.

If you can do your own anodizing then you are in a position to touch up any of your stuff in a jiffy.

[TimAckerman]

Wow, very cool, and very straightforward!

Thanks for sharing Don.

[exodus125]

where can you get ammonium sulfate?

[precisionworks]

anodized titanium for the most part to be a cosmetic feature

There are commercial firms that can apply thick film anodizing, primarily to reduce Ti-to-Ti fretting and galling on sliding fits or threaded fits. I've had a few phone discussions with a sales engineer at TFC, one of the larger companies that anodizes. They recommended a (not too pretty) mechanical coating called Ti Fin 400, which they state is very thick relative to the natural oxide layer always present on raw Ti - which has a range of only 50 to 250 angstroms, what I'd call nanoscopic.

As much as I'd love to try this, I can't bring myself to send the PD-S ...

http://www.titaniumfinishing.com/page09.htm

Here's an article on the soda method (which I have not tried):

http://www.popsci.com/diy/article/20...um-technicolor

[McGizmo]

Barry,
When I was into anodizing Ti in making earings, I would often anodize and then take diamond burs to break through the film so that I could then apply a lower voltage and only color that which had been freshly exposed. I found from goofing around that if I zapped the metal with a high voltage (90v I would guess) that the oxide layer didn't really have a color but did have an interesting iridescence to it and this layer was a real challange to break through. Bead blasting really didn't cut it and only the diamond burrs really were effective.

I think this may have been similar to the finish you have referenced. When there were discussions here about galling of Ti, I recall thinking that one solution would be to anodize one "side" of the threaded couple with just such a film so that you would have a hard VS soft mating. Probably even better with both threads sporting the hard film?

I qualified the anodize as strictly cosmetic even considering this exception though because at the point you get the hard and thicker film, you no longer have any real color so it is not cosmetic in the sense as the colors would be considered. I believe you can also get a hard surface from some forms of heat treating. When I used to mess around welding Ti, I would get I think it is called an Alpha film or layer on the surface and man, that had to be ground with diamond for sure! Brittle as hell too! I welded up a Ti windsurfing harness hook assembly that looked really cool and weighed nothing compared to the stainless ones. While board sailing between Maui and Molokai, with it on the virgin run, I heard one weld after another snap! Fortunately the way I formed it, none of these welds breaking caused a catastrophic failure. I came to accept the fact hat my welds were cosmetic and not structural.

There is no welding involved in our lights so these issues of how easily Ti can be contaminated and compromised at elevated temperatures are not considered. For the fun of it, I would like to get a Ti light heat treated sometime. The metal color and surface is really different and unique after heat treatment and the members who talk about how soft Ti is have clearly never messed with a heat treated 6-4 piece of Ti!! (Of course the naysayers would then criticize the metal as being too brittle )

[oregon]

I've gotten Ti, Spyderco Salt series knife pocket clips are Ti, to show color using a strong dose of household drain cleaner and a small amount of water. Is this anodization? I don't know but I was surprised by this iridescent result.

oregon

[Th232]

When I used to mess around welding Ti, I would get I think it is called an Alpha film or layer on the surface and man, that had to be ground with diamond for sure! Brittle as hell too! I welded up a Ti windsurfing harness hook assembly that looked really cool and weighed nothing compared to the stainless ones. While board sailing between Maui and Molokai, with it on the virgin run, I heard one weld after another snap!

Ouch! What gas (if any) were you using to shield the weld? When we were laser welding some CP Ti at work, proper gas shielding made a ridiculously big difference. Never saw any difference from a visual inspection, but the results were very obvious.

[McGizmo]

oregon,

I would guess you are growing an oxide film thick enough to give you some light interference and hence color.

th232,

I have a TIG set up and do and did use argon. To do it right though, you almost need a chamber that is sealed and filled with argon. The other problem I likely had was one of contaminated welding rod and surfaces on the parts being welded. I believe nitrogen embrittlement (sp) is a common problem and perhaps one I experienced.

I read a story once about some forged titanium struts used either on the shuttle or perhaps a military craft that would fail. It took some serious investigation and it turned out that in the summer time in CA, the local water supply was enhanced with additional chlorine because of evaporation. The forging process used municipal water for cooling and this chlorine reacted with the heated Ti during the forging process and compromised its physicals. If I'm not mistaken, some of the early bike frames of Ti had some unexpected and uncool weld failures. I once met a guy who was a professional welder and he told me of a job he had where he would enter an inert gas filled room wearing a closed air supply suit so he would weld titanium without compromising the welds!

[exodus125]

this may be a dumb question, but can you use a battery charger to do this, the type you charge car batteries with?

[exodus125]

Here are a few pictures of some pieces I heat anodized today.

[KuKu427]

Typhoon day in Taiwan, no work, no stores open... No better time to re-anodize my light!
It was purple, now its teal... 5 9volt batteries and good old coca cola.

[kaichu dento]

Typhoon day in Taiwan, no work, no stores open... No better time to re-anodize my light!
It was purple, now its teal... 5 9volt batteries and good old coca cola.

Kuku,

Can I have that one?!?

[Zeruel]

Typhoon day in Taiwan, no work, no stores open... No better time to re-anodize my light!
It was purple, now its teal... 5 9volt batteries and good old coca cola.

Did you anodize over the original purple? Or did you manage to remove the purple first before doing it in teal?

[KuKu427]

Kuku,

Can I have that one?!?

Kaichu, Sorry! That's my personal light and it's not for sale. Another thing is that it's a little splotchy in places. I don't think I did a good enough job to sell it.
But here is a high-resolution picture for ya!
www.expandku.com/lf2xtiteal3.jpg

Did you anodize over the original purple? Or did you manage to remove the purple first before doing it in teal?

Zeruel,
I took the purple anodizing off with a scouring pad. It got just about everything except what was in the grooves of the knurling. Then I anodized it at 18V and got a really ugly brown/purple. Then I went to 5x9V and got this color. You don't need to take off anodizing that was on there already if you plan to go over it with a higher voltage.

[KuKu427]

Finally! Even uniform color!

[oregon]

Beautiful! The terrific blue really comes across in the photo. Very attractive. Did you do this in the dark with the power off?

Was there much damage from the storm?

oregon

[Benchiew]

here are some high polish anodized pieces:

These are nice.

[wquiles]

Bump to a very awesome and informative thread

[tino_ale]

This is my 365nm UV Mule, glass bead blasted then anodized to a slightly purplish deep blue.





This is a "champagne" pink I am pretty happy with for any girly gift


And this is the best blue I could get so far