titanium watch galling?

[generallobster]

titanium has the property of galling and potentially cold welding when in contact with another piece of titanium correct? In titanium diver watches, does the case back or crown eventually gall badly enough to prevent opening the case?

 

[fishbulb]

I've never seen it happen, and with the relatively infrequent short-duration low-speed movement between the parts you mention I don't think it's a practical concern.

There are plenty of ti/ti interfaces that are cycles more frequently and under more load than a watch case, and I'm not aware of this being a special concern with them. I wouldn't worry about it.

 

[JCaswell]

In general:

Threaded interfaces (Ti to Ti) can be a particular problem.

There are ways to prevent this. There are 'assembly lubes' specifically designed to prevent Ti from bonding to itself or Ti and aluminum which will also stick up pretty well.
There are permanent finishes that can prevent this too, but they're usually pretty expensive.

A teflon-based assembly lube for Ti (and other things) I've been using is by Dupont. It's called Krytox, IIRC. About $30 for a little tube, but for this sort of thing it lasts a very long time.

 

[65535]

I think most quality manufacturers take into account Ti galling and coat all contacting parts where they mate to prevent Ti galling which as you know is a huge problem especially in threaded components.

 

[tirod3]

My Ti watch case has no threaded back. It's solid.

I've used Krytox on stuff, it's pretty good. But the point is how much movement is required to get ti to gall. Screw on watch backs probably aren't nearly enough. IMO it would take a repeated, cycling action - like band links, which probably have too much clearance to be a concern.


As for actually welding together, that's an interesting phenomenom I'd like to hear more about. Sounds like metallic silly putty.