It took quite awhile but it is brazed and ready to fit to the front triangle. Fitting the tubes took a lot of time with my limited tools. It isn’t perfect but that is not the point of this exercise. I’m experimenting with this bike design to try and solve the weight distribution problems. I’m also using it as a learning exercise for bike fabrication. Here are some things that I discovered.
Tube fitting is hard to get right with just hand tools. It takes a lot of trial and error to get the many curves and angles to fit together. It is critical that they fit without large gaps so that they can be brazed. Someday I will have a mill or a tube notcher.
Welding provides many challenges. I spent a great deal of time reading up on all the techniques and material combinations. There is a lot to know in order to make good strong welds safely. It is critical that the welds are strong and won’t break. If the bike breaks apart while riding at high speed, injuries are likely. Since this is an experiment and I’m still learning, no one but me will ride this bike. If you are going to be doing this for yourself or others, don’t rely on my advise. Take a class, read, learn how to do this correctly and safely. There are more hazards than just the strength of the weld. There are explosion hazards as well as toxic fume hazards. Make your own choices; I am not responsible for your actions.
Metallurgy is an interesting topic. There are many variables to consider when choosing metals, filler materials and welding techniques. Some of the information is contradictory which makes it even harder to choose what to use. I won’t go into all of that now. I chose to use the traditional brass rod with flux and fillet brazing as described by Paterek. The fillets seem be be very strong but I won’t know if they will hold up until I add all the weight.
Many bikes are fillet brazed using brass rod with flux. Here is what I used for this project: Gasflux C-04 brass rod 1/16” and Type “B” paste flux. My torch is a Smith AW1 with AW203 tip.
The alignment of the fabricated tubes was fairly easy for this part of the project. I used a tape measure to get everything lined up. Heat distortion caused some of the alignment to change from where I had it set. I don’t think this will be a problem for the rear triangle. This could be a major problem though when fitting the rear triangle to the front triangle. I’m going to have to build a jig to keep it all in line. Just using a tape measure and string isn’t going to cut it.
What’s next? I’m going to build a jig to hold the front and rear in line, fabricate the other tubes needed to connect the front and rear, weld it all together. A new camera arrives this week so stay tuned for more videos.
Click on comments below. Let me know what you think. Ask any question. Tell everyone your techniques or how to do these things better. Share your opinions.