[Baldone]

I once was told that there may be a problem using a Titanium bolt in a Titanium hole that it would eventually weld itself together, can anyone confirm this?

Would an Aluminum bolt have the same problem?

Thanks.

 

[tlg]

I once was told that there may be a problem using a Titanium bolt in a Titanium hole that it would eventually weld itself together, can anyone confirm this?

Would an Aluminum bolt have the same problem?

Thanks.

This is not correct. Titanium will not react to itself. It is a non corrosive material. The problem is using titanium with other materials.
http://www.stainless-steel-world.net/titanium/connecting.asp
http://www.corrosion-doctors.org/Aircraft/galv-design.htm

Aluminum bolt in an aluminum hole can be a problem. Aluminum is corrosive and can "weld" itself to aluminum or other materials rather easily.

 

[bulC]

true facts

This is not correct. Titanium will not react to itself. It is a non corrosive material. The problem is using titanium with other materials.
http://www.stainless-steel-world.net/titanium/connecting.asp
http://www.corrosion-doctors.org/Aircraft/galv-design.htm

Aluminum bolt in an aluminum hole can be a problem. Aluminum is corrosive and can "weld" itself to aluminum or other materials rather easily.

While ti will not exchange electrons with ti and so not "weld" itself to itself, there is an issue here. Ti will gall and seize because unlike most metals, it is flexible enough to deform around the threads so the hole kinda grips the threads, kinda like screwing a bolt into your fist. Bad analogy no doubt -- that's how a Famous Ti Frame Builder once explained it to me -- but the end result is removal problems later. No maker of ti square taper BB spindles, for example, recommends using a ti crank fixing bolt for this reason.
That said, a liberal application of Finish Line Ti-prep antiseize will all you to thread ti into ti without worries. Emphasis on the word "liberal," really slather it on the threads, coating them completely so some oozes out.
Aluminum bolts anywhere in a bicycle on which you depend on reliability so's not to kill yourself, is a dumb idea.

 

[Baldone]

Thanks

Thanks for all the good info, It is for the tension bolt on a Ti Brooks Saddle the rails and structure being Ti the bolt being steel. I still needs to hold the tension.

So aluminum is bad with an aluminum hole. How is aluminum with a Ti hole?

This bolt is huge, probably larger than an M8 so I am thinking aluminum should work and if it does fail my seat becomming untensioned won't be a problem involving life and death.

 

[tlg]

Thanks for all the good info, It is for the tension bolt on a Ti Brooks Saddle the rails and structure being Ti the bolt being steel. I still needs to hold the tension.

So aluminum is bad with an aluminum hole. How is aluminum with a Ti hole?

This bolt is huge, probably larger than an M8 so I am thinking aluminum should work and if it does fail my seat becomming untensioned won't be a problem involving life and death.

Aluminum is bad with just about anything if not properly protected.

http://www.stainless-steel-world.net/titanium/connecting.asp
Titanium should not be coupled directly to less noble metals, such as magnesium, zinc, and aluminium. These are likely to experience accelerated corrosion and, in the process, titanium may pick up hydrogen which is generated as the cathodic product of the corrosion reaction.
http://www.thelenchannel.com/1galv.html

If you have to use the alum. bolt, use lots of grease (preferably waterproof).

 

[Baldone]

Sounds like Steel maybe the only way to go.

Nice links.

Perhaps its not worth the hassle, I may get a shorter Steel bolt to use for the mean time. The Ti would be expensive and the lube for that or the Aluminum might be gone by the time it was time to adjust the tension, and that would be ugly!

 

[tlg]

Nice links.

Perhaps its not worth the hassle, I may get a shorter Steel bolt to use for the mean time. The Ti would be expensive and the lube for that or the Aluminum might be gone by the time it was time to adjust the tension, and that would be ugly!

Get a stainless steel bolt.

 

[Baldone]

Will do tnx

Get a stainless steel bolt.

Will do!