# The colour of Titanium.



## Anglepoise (Oct 6, 2006)

While there seem to be lots of different grades of Titanium out there, I believe I am correct in the assumption that only Grade 2 ( pure) and Grade 5 Ti-6AL-4V are being used by members here.

While I am aware of the colour balance of different cameras I am interested in the different shades of Ti.

Member TB's all have a gold tone when seen on this site, but suspect that is his lighting set up and camera.

If someone owns lights made form both Grade 2 and 5, would they be so kind as to take a pic with both lights in the same shot.

I am told that Grade 2 is a much darker than other grades.

With all the mix and match modding items, it might be a good idea for all of us to take more interest in the grades used in manufacturer by the modders selling these items.


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## Long John (Oct 6, 2006)

Hello Anglepoise

The titanium grade 5 (mixture of AL and TI, Vanadium) is often used by knifemakers, because it's much harder than pure TI. For liners and handles.

It looks a little more greyish than pure TI, but at last the manufacturing of the surface is the most important reason for the finish. If it's polished or dulled, anodized in one or different colors.

So you will see a difference in finish between different TI-lights on a picture, but I doubt to perceive the different grades on a picture, specially in a reduced pic for the net. But that's only IMO.

Best regards

____
Tom


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## McGizmo (Oct 6, 2006)

Anglepoise,

I have read some comments in various threads about the color of Ti and speculation that a particular alloy may have a different tint or hue than another.

I have been messing with the metal for a number of years and I have seen a number of different faces of Ti. I don't think the alloy can be identified by its color. I could be wrong and it would be great if there was a visible signature to alloy but I just don't think it is possible for us to use it, even if it is there. If a CP coupon and 6-4 coupon were machined with the same tools and brought to identical surface finishes, it would be curious to see if a different tint or hue resulted. Over time I would guess the parts could change relative to each other.

Consider anodized Ti where there is no coloring agent present in the metal; merely an oxide film with difference in color depending on thickness of film. Ti oxidizes almost immediately and the film thickness of the oxide will vary from part to part depending on the environment and possible contamination of the surface of the material when it did oxidize.

The surface finish of the Ti plays a big role in the color or hue perceived. Surface contamination also plays a big role. If you anodize a part with a light blue color for instance, the oil from your hands will darken the tint of the blue. If you take any Ti part that has been handled and wash it with dish soap, you will quite possibly notice a change in appearance and color afterwards.

You have a clear oxide film that is transparent and this film follows the surface shape of the parent material. Light reflects off of the film surface as well as the parent surface below. I have no idea what it is but it is reasonable to believe that the ti oxide has a refractive index and this refractive index may even vary with the means of the oxide growth?!? There is no doubt light loss in this film and the thicker it is the greater the loss I would expect. The greater the light loss in the film, the duller or darker it would appear next to a part with thinner but similar surface texture and form.

Ti, regardless of alloy, plays with light and alters the amount and direction of returned light in ways and means not found in most other materials; other refractive metals aside. Ti is no shape changer but it is a color changer par excellence! It really messes with light!!!

I have seen polished and machined Ti that is hard to tell from stainless steel or even chrome. There are certain surface finishes as well as heat or anodize treatments that put Ti in an appearance that can't be achieved with the other metals. A fine bead blasted or randomized surface part for instance can end up with a smokey hue that I believe is the "signature" of Ti and the color that is emulated by paints and anodize films targeting the Ti color. :shrug:


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## Anglepoise (Oct 6, 2006)

Thank you gentlemen for taking the time to reply.


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## Calamityville_Horror (Oct 6, 2006)

I was in the process of replying, but I see McGizmo has basically covered anything I had to say. :goodjob: 

I have seen titanium machining produce chips of many colors. The specific color depends on the temperature of the chip as new metal is exposed to air, I believe.

This may be worth a read.


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## Anglepoise (Oct 6, 2006)

As it comes out of the lathe, finish turned, member ArsMachina maintains that
Grade 2 is much darker than Grade 5. No heat, no anodizing, just bare finish turned TI. My only experience to date is with ASTM B, Grade 5: Ti-6AL-4V and
that , as said above, is very close to SS in appearance.

Still hope for a photo.


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## kenster (Oct 10, 2006)

Anglepoise, lighting can make things appear different as you said in your first post. This is the same Tranquility Base made Ti battery tube in both pictures. It wasn`t as highly polished in the first photo but it doesn`t even look like the same metal because of the lighting and camera settings.


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## modamag (Oct 12, 2006)

Anglepoise,

I second what McGizmo stated regarding the tint, temp, & tooling. However, I have the opposite experience of what ArcMachina have on Ti regarding the CP vs 64.

Bellow are some pictures of Draco part/prototype made from SS, CP & 64 while I was trying out knurling, threads and finished. None of them have went thru polishing yet.

These images were taken in RAW then post processed with only Level-Set White Point (background).

Click on the picture for larger view.









As you can see the CP is darker than SS and lighter than 64. Now if I polished this up, the Ti parts would be a little darker even after some oxidation period.

I hope this help. Have fun machining.

Enjoy,
Jonathan

BTW: Thank you for giving me an excuse to play with my new toy.


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## Anglepoise (Oct 12, 2006)

Jonathan,
Thank you for taking the time to post and answer.
My original concern was about mix and matching parts from different Ti grades.
I am keen to experiment more.

Thanks to all for your posts....


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