Cycling UK Forum

I have seen several grade9 (3/2.5) titanium frames

• Some painted, typical of the 90's. Not a good idea, in my opinion.
• Some are bare titanium, because it doesn't rust. Best idea, in my opinion.
• Some are mirror polished titanium. I just don't understand this.

Litespeed (USA Company) has several finishes for their "Classic" frames in their catalog.

Some are bare titanium.
Some are mirror polished titanium.
I don't understand how you can get mirror polished titanium.
It looks very similar to chrome plating on steel.
But chrome plating is a chemical process of coating a steel product with chromium.
And the result is a light color and can be polished to a mirror finish.

And, if you have a mirror polished titanium frame, can you restore the original color, i.e. a bare titanium frame?
If so, how? Just brush?

... mumble

DiTBho wrote: ↑3 Oct 2024, 2:41pm I don't understand how you can get mirror polished titanium.
<snip>
And, if you have a mirror polished titanium frame, can you restore the original color, i.e. a bare titanium frame?
If so, how? Just brush?

Physical methods involving very fine grade sandpaper followed by a buffing wheel. Electro-polishing (basically like anodising). Chemical polishing which uses acids etc to smooth out surface imperfections. Or you can blast it with a plasma beam. Or a combination of the above.

Also, NO you cannot restore it to matt finish by brushing it, that'll just polish it more! Once it's polished, it stays polished!

I'm not sure what bare titanium looks like, the three common finishes we see are, bead blasted, brushed and polished. Even within those there's some variation, I had a brushed frame that was almost polished, the brushed marks much finer than usually seen. All the finishes dull with age, though they can all be restored by re-doing the original process.

rareposter wrote: ↑3 Oct 2024, 2:58pm Also, NO you cannot restore it to matt finish by brushing it, that'll just polish it more! Once it's polished, it stays polished!

Not sure anyone would want to, but what would happen if you bead blasted a polished frame?
There are some ti frames where the decals are bead blasted onto a brushed or polished finish, at least I've assumed that's what's been done, rather than brushing around the lettering.

IME a lot of 'raw titanium' finishes are actually bead-blasted. If done correctly, bead blasting can improve the fatigue life of Titanium welds, by introducing a compressive residual stress at the surface. Whilst any metal can be polished (hence metallography) it seldom comes with such benefits. Bead blasted finishes can usually be locally repaired.

rareposter wrote: ↑3 Oct 2024, 2:58pm you cannot restore it to matt finish by brushing it, that'll just polish it more! Once it's polished, it stays polished!

Are you 100% sure about this?
There are no exceptions?

Brucey wrote: ↑3 Oct 2024, 3:36pm IME a lot of 'raw titanium' finishes are actually bead-blasted. If done correctly, bead blasting can improve the fatigue life of Titanium welds, by introducing a compressive residual stress at the surface.
Whilst any metal can be polished (hence metallography) it seldom comes with such benefits.
Bead blasted finishes can usually be locally repaired.

I have seen some raw titanium frames built in the 90s.
I don't know what process they went through though.
They look like they ran sandpaper strips over tubes after welding they together.

DiTBho wrote: ↑3 Oct 2024, 4:27pm I have seen some raw titanium frames built in the 90s.
I don't know what process they went through though.
They look like they ran sandpaper strips over tubes after welding they together.

That sounds like the brushed finish, it's scotchbrite rather than sandpaper, but you can see the pattern.
Here's the range of finishes Enigma offer:

https://www.enigmabikes.com/pages/frame-finishing

I have a Citizen titanium watch which is polished to a shiny finish.

PH wrote: ↑3 Oct 2024, 4:36pm....That sounds like the brushed finish, it's scotchbrite..

arguably the bushed finish is the easiest to live with because you can renew the finish using just a piece of the special scotchbrite, whereas renewing a bead-blasted finish requires fancy equipment.

How titanium are titanium frames? If they are an alloy - with what?

I bought a couple of cheap titanium long handled spoons with a rough (bead blasted?) finish that I didn't like in my mouth, so I polished them smooth. I couldn't get a mirror finish on them but they felt better in the mouth. By price alone, I wouldn't expect them to be 100% titanium but they were hard to polish off the rough texture.

freiston wrote: ↑3 Oct 2024, 10:52pm How titanium are titanium frames? If they are an alloy - with what?

From memory its about 95% titanium with the other 5% aluminium and vanadium. When I was looking at having a titanium frame built all the manufacturers, across the price ranges, were using the same grade (Or one very close) It was rumoured the rise in the popularity of titanium about twenty years ago was down to the decommissioning of the USSR submarine fleet, I have no idea if there's any truth in that.

DiTBho wrote: ↑3 Oct 2024, 2:41pm I have seen several grade9 (3/2.5) titanium frames

grade9 (3/2.5) means

• O: 0% min ... 0,15% max
• N: 0% min ... 0,03% max
• C: 0% min ... 0,08% max
• H: 0% min ... 0,015% max
• Fe: 0% min ... 0,25% max
• Al: 2,5% min ... 3,5% max <-------- that's where "3" comes from in "3/2.5"
• V: 2,0% min .... 3,0% max <-------- that's where "2.5" comes from in "3/2.5"
• Ti: the rest

And the alloying with metals other than titanium is done to improve the properties of the finished product, not to save on a bit of titanium.

PH wrote: ↑3 Oct 2024, 4:36pm

DiTBho wrote: ↑3 Oct 2024, 4:27pm I have seen some raw titanium frames built in the 90s.
I don't know what process they went through though.
They look like they ran sandpaper strips over tubes after welding they together.

That sounds like the brushed finish, it's scotchbrite rather than sandpaper, but you can see the pattern.
Here's the range of finishes Enigma offer:

https://www.enigmabikes.com/pages/frame-finishing

Enigma do not show full mirror polishing on that link but they can do it; a bit expensive and high maintenance for many and probably why they don't bother listing it as it's just not popular enough to showcase. 'Brushed' or 'bead blast' finish with contrasting panels are by far the most popular.