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I'm building (experimenting if you wish) something out of the old bike parts and I need to fix two parts together one titanium and carbon.

Basically the parts are two tubes one made of carbon of a lower diameter and one made of titanium. So the carbon tube goes inside the titanium tube and I need to find a way to fix it inside for good. I guess it should be some kind of a hardcore gluing.

If anyone have any experience or suggestions please share. Thank you!

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    Such connections are usually made with epoxy resin or epoxy glue. I'm affraid the specific substance is a matter of experiment as well... – Slovakov Mar 17 '15 at 11:57
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    I would think some serious Googling in the material sciences section of the world would be your best bet. What little understanding I have of it leads me to believe you'll need some sort of oven/kiln to cure the resins/glues, as well. – FreeMan Mar 17 '15 at 12:40
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    I would guess than in addition to glue there is some butting involved as well. It's all well and good to glue/epoxy/resin it in place, but to survive the compression forces, the tubes need to be firmly pressed into each other, not just glued in place. – Deleted User Mar 17 '15 at 16:02
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    Found some reference for fiberglass to metal with just a basic epoxy. In general this is just a bad idea as they have different flex patterns. Carbon fiber frames are built up from a single mold for a reason. – paparazzo Dec 4 '15 at 19:16
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    There are several companies out there making titanium lugged carbon frames. Sending off an email to one as an "interested buyer" may fairly easily get you the answer you are looking for. – Deleted User Dec 4 '15 at 20:41
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+200

There are many companies today producing "lugged" frames out of aluminum/steel/titanium with carbon fiber tubes. Seven Cycles is one example, but there are others. Additionally, some people are independently making carbon frames with lugs that have been created using 3D printer madness. Reading various forums and the last link, 3M, Loctite and West System all make epoxies that would work for such an application. Your best bet would likely be to contact the company and have them recommend which product would be appropriate.

All of this assumes that you are trying to lug a piece that will be under compression. Lugged bicycle frames work because the triangle largely experiences compression forces which actually force the tubes into the lugs. Forces acting to pull the tube out of the lug are more rare and the epoxy acts mainly to hold the setup together and isn't as "structural" (bad use of the term) as the lugs or tubes. If this is not what you are trying to accomplish, you may look for a different solution since gluing/epoxying together two pieces that will be under tension will rely on the strength of the epoxy to hold them together and likely not be appropriate for the forces generated cycling.

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You could try epoxy as a start (I usually use EpoFix).

Remember to: - sand and roughen the contact surface - clean the surface by alcohol to dissolve any grease/oil - mix epoxy and glue the two parts together. - note that if it is your first time mixing epoxy, you might want to practice before making any kind of permanent structure.

This epoxy adhesion is plainly for adhesion for obvious reason. Torque and pulling/compressing in the beam axis are ok. However, any extreme bending/loading on lateral direction my cause failure to the adhesion.

You could try to patch this up by adding an outer layer of carbon fiber+epoxy (~4 layers) on top of the initial adhesion. This improves the structural characteristics of your joint.

If you could advise which part of the bike you are working on, I might be able to give a more detailed answer.

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