riveting alu to titanium

[christopher67]

I need to replace a rivet that is holding an alu part to a titanium tube of a 35 year old bicycle. The rivet is quite rusty.

It will see only mild weather, and will mostly be inside, with possibly an occasional exposure to rain.

What material rivet will be best for this application?

 

[3DDave]

What do you mean by "best?"

If the rivet has held for 35 years a similar, probably steel, rivet would likely work for another 35 years.

How large is the body of the rivet? How much material is being retained by the rivet? Do you have access to both ends of the rivet? Does neatness count? Is it where one end of the rivet can be placed on an anvil while smacking the other end with a punch without damaging the tube? Is it a hollow rivet? If it is inside a tube, can you get a metal rod into the tube to support the head of the rivet inside the tube and take the load of forming the rivet head on the outside? Could you use a small screw and a nut and some locking compound, give it a good snugging and then grind the head to a rounded shape that would not snag things?

 

[christopher67]

Hi and thanks for the reply. It's a high end mountain bike frame from 35 years ago. I would like a replacement rivet and am not sure what material is best to ensure it does not react with the other parts.

 

[EdStainless]

Considering how much the Al and Ti react with each other (with the Al being attacked) I don't see that the rivet material matters.
Use what you can get that fits well.

 

[christopher67]

Thank you.

I am not 100% sure the other part is aluminium. Is there a simple way to get clarity on this without damaging it? I'm not sure I am seeing any corrosion on the part, but the hue is slightly different. It could possibly be titanium.

The tube is for certain 3-2.5 Ti.

I am assuming the rivet is not stainless since there is so much rust? Or is it possible that the contact with the titanium makes a stainless part react so strongly?

 

[LittleWheels]

Ti is more noble than stainless, though quite close together in the galvanic series. IMHO, it wouldn't be hugely surprising if a stainless rivet corroded over 35 years.