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Old 07-06-12 | 08:28 AM
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Scooper
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Joined: Aug 2005
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From: Santa Rosa, California

Bikes: Waterford 953 RS-22, several Paramounts

Randy, I'll take a stab at answering your question.

Ti alloys have an ultimate tensile strength and yield strength similar to 4130 steel, but a Young's modulus significantly less than steel (105-120 GPa compared to 200 GPa for steels), so to provide the same strength and stiffness as a steel tube with the same diameter, a Ti alloy tube has to have thicker walls (as much as twice as thick). Since the density of Ti alloys is about half that of steel, the thicker walled tubing will still weigh slightly less than the steel, but because the walls are thicker rolling out dents in a Ti alloy tube would be more difficult than rolling out dents in a steel tube. Compounding the thicker walls problem, Ti is less ductile than steel.

Dents can never be rolled out completely, so after rolling a steel tube the remaining deformation can be filled with brazing material, lead, or bondo, faired so that the deformation is not visible, and then painted. While dents in Ti can be filled with bondo, it would have to be painted to cover up the repair.
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