I recently attended classes a the united bicycle institute in ashland oregon. The class was specifically involved with frame design and TiG welded Double butted chromoly.
     TiG Stands for Tungsten, which is used for the electrode, and Inert Gas, namely argon.
     The Argon creates an air-free environment, surrounding the weld area and creating a stronger bond, with less oxidation.
     We used Columbus' Nivacrom, which is Niobium, Vanadium, Chromium, and Molybdenum.
     The class was excellent. We were welding scraps the first day. We used Miller Maxstar 151 welders, with snap start and pulse controllers.
     The pulse controllers vary the strength of the electric arc, allowing you to get 100% power for the welding process, but then dopping the power to a lower level. This gives the weld that sought after 'stacked dime' look, and also lessens the heat affected zone. The heat affected zone is the part of the tube in which the crystaline structure of the metal is changed to a slightly weaker form.
     This is the point of contention between brazers, and welders. Brazers claim that the lower heat required for this type of work creates a lesser heat affected change, while welders believe that the shorter duration of more intense heat is less destructive to the structure. We did do a little brazing on our bikes. The bottle bosses and the cable guides were brazed on, and some students followed one instructors reccomendation that the brake bosses should be brazed as well. The more confident welders, welded their bosses on.
     The class is strictly diamond frame oriented. The jigs (and there are many used) are designed completely around the typical angles of a standard bike. When I wrote the school they said, "you may only build a mountain, road, trails, or cross bike". I therefore dicided to build the longest, lowest diamond frame possible.

I intended to build a BMX type frame onto which I could weld a front boom, with a sliding bottom bracket attachment. When the design portion of the class began, I measured the jig at it's maximum dimentions, and figured I would be fine. I realized that I would have to do more welding than the others, but was confident at that time that I would be able to finish on-time. I did not realize at that time that I would not be able to jig the front boom tube onto the head tube, nor did I realize that my odd shaped rear triangle would conflict with the jig designed to hold the seat tubes in place during the welding process. I ended up asking the director, Ron Stuphin to hold my seat ubes in place while I tac welded them. I almost forgot to mention that the tube mitering jigs also could not accomodate the extreme angles required for some of my miters, so I had to hand miter them with a hacksaw and files. When it came time to cut my top tube, I realized that the only way I would be leaving with a complete frame was if I could pierce my top tube, and and fit the head tub through it. Since the top tube would be straight, this left me with a very high front bottom bracket location(app. 36-39 inches above ground, with a suspended 20" fork).
     The school had never produced a pierced top tube frame(in fact they consider it bad tool use), and I was hesitant to bring the idea up. I could hear the instructors now "Yea, we had a guy build a recumbent. What a pain in the...." I did not want that. Luckily I was not the only oddball in our class. We had a Flatlander(bmx) rider in our class, and he really wanted a bmx bike. He talked them into letting him pierce the back end of his top tube, where the seatpost would go through. Once I saw that, I decided to make my desires known.
     Due to my odd design, I had to use straight walled tubing for my top tube, and it had to be oversized(diameter). This also meant that we had to squash the tube before mitering it so that there would be no gaps where it attached to the seat tube. One instructor griped a bit about having to re-center the milling machines to accommodeate my oversized tube, and I had to wait until all the other students had finished their miters, before the machine could be reset. This and the fact that I had about 25% more welding to do put me a bit behind. I also had to tap and thread two bottom bracket assemblies, and so that I might be able to accommodate a 26 in. rear wheel or a 20 in. I attached to sets of brake bosses to my rear triangle, and had an extra braze-on to clamp the sliding front bottom bracket assembly in place. I used a seat tube braze-on.
     I was rushing a little at the very last day, as I also had a little extra weld filing and tube reaming to do.
      All in all, if I go back to UBI for their TiG welded titanium class, I will probably build a traditional bike. Even if I don't ride the thing, it will look great on the wall.
     P.S. please don't go to UBI and tell them, "But you let him do it!" I plan to return to this school often, and don't want to earn a troublemaker rep.

I am currently open to offers of employment in the bicycle industry. Full time or seasonal employment will be considered. I currently reside in South East Texas, and spend a couple months of late summer in Michigan, and sometimes early summer in the Colorado Springs-Denver Area.
If you have questions or comments, you may contact me at antlercarver@aol.com

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