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riveting alu to titanium 1

christopher67

Mechanical
Feb 4, 2025
14
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?
 
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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?
 
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.
 
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.
 
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?

113d5eb3-ffd4-4a8f-8e31-ae540374c86b.jpeg
 
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.
 
Here is a picture of a second, identical frame, maybe the difference in hue is more clear on this one.
To me the cable stop looks like aluminium.
Maybe there is a layer of epoxy or a gasket of some sort between the two parts for shielding.

1738751544433.png
 
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The small part looks like an extrusion, which will be some sort of aluminum. The rivet appears to be a plain steel rivet. Keep the frame out of salt water.
 
The cable guide is Al, the rivet is steel.
The rivet was originally coated or plated.
What frame is this?
I have an old Al frame with an identical feature but they used and Al rivet.
 
I would consider removing the rivet and using an acrylic epoxy to attach the guides.
 
I would consider removing the rivet and using an acrylic epoxy to attach the guides.
The continuous sheer force between the frame and cable stop of two wires (rear brake and front derailleur) in stretch may be too much for the epoxy without rivets. There must be a reason why it was built that way in the first place. Also visually, the rivets are needed, this is a layman restoration of a rare American made titanium frame, from the early "neon" days of mountain biking. Part of my collection.
 
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If appearance is the concern, drill the rivets out and replace with stainless.
 
Cool 🚲👍

Red rust on the rivet pretty much rules out aluminum.

A magnet will probably tell you if it's steel or stainless.

The cable stay looks like it might be plated. Scratches, so probably not chrome. Maybe nickel. Maybe just a really nice clear anodized finish.

Regardless, use a stainless rivet with retained stainless shank for replacement. Install it "wet" with automotive clear coat.

It's the top tube open to the seat tube or head tube? Getting the remnants of the origin rivet out of the to tube is going to be hard.
 
Yep, there's a hole to the head tube. Ha, imagine riding around the countryside with that things rattling in there, might get a fan club of cows.

1000019427.jpg
 
I rode a Teledyne Titan for a while.
Those made so much noise that you couldn't surprise the other riders in you group.
As soon as you leaned on the peddles they could hear it.
 

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