Once the miters are all good and the geometry is the way I wanted, the welding commenced. Braze welding is an art and I was starting from a big disadvantage.
- First time using my torch
- First time on S3 tubing
- First time fully brazing a whole bike
- First time using this type of flux and brass
Most builders would rightly start out on some cheapo tubing set and then move upwards to finally getting to S3. I have a slightly different philosophy and mush less wise one. I like to learn on what I plan on building with and know that if you can do the hardest stuff, then you can do the easy stuff if you want to later. I also acknowledge that I may have to redo and start over a lot in order to figure it out. I did a decent amount of practicing with some old tubes before I started. This was obviously needed just to get used to the setup, heat control and to learn how the brazing material behaves.
I did have one advantage, my buddy at Rabid Frameworks has popped out so many bikes with the setup I am using that he has a lot of lessons learned to share. He also was able to be a resource for me to bounce questions off of and to brainstorm solutions together. We actually were able to do some late mods on the frame late into the build together. Another advantage – I was in no hurry. The frame ended up taking 4 months to build because I wanted to use this build as a prototype and to take the time to learn.
I have attached a variety of my welds as I went. As you will see they were pretty pathetic. I am confident in their strength, but the finish was awful. I kept having contamination from the torch due to build up and incorrect settings on oxy vs propane. I also didn’t have a good sense of how to create a consistent depth. I also didn’t understand the finish process and had to keep going back and redoing joints after finishing them up and not liking the results. Eventually I was able to understand more about how to build up the brazing to create the finish affect I wanted. But the heating and reheating caused a lot of warping of the steel and probably isn’t the best experience for a steel frame to go through. I was able to get it all back to where I wanted and to finish it off in a professional way, but I got there the hard way. (No surprise based on my philosophy of trying to race with the pros as soon as I decided to race a bike.)
One thing that happens a lot with this kind of tubing is that it warps. Things like the head tube ovalizing or the bottom bracket bananerizing or the seat tube bulging seem to be quite common for amateurs. I learned how to avoid this and how to fix this as I went through the process.