Sunday, January 22, 2006

recumbent bike skills

One of the skills that is involved in making bike frames is braze welding. My understanding of it leaves something to be desired but hey what the heck... I wish I had found this guide before I had attempted this awful piece to the right.

Heat is the key to good brazing and obviously I didn't have enough. I was heating with MAPP gas. Later (after filing all that junk off) I used a propane torch and a MAPP torch. That was enough heat for this joint and one other small joist but not enough for larger joints. When the joint is properly hot the alloy, copper, in this case, will flow like water , not bead up. The beads in this show a cold tube.

This weekend was a good weekend for learning what not to do. I tried to shape a piece of cromoly tubing by packing it with sand and using a bicycle wheel to get a good radius. I didn't pack the sand nearly tight enough, crimping my tube. If you try to shape tubing this way ensure that you have packed the sand extremely tight. Avoid crimped tube! Do not get in eyes! Dilute! Dilute!

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