Joining parts (tubes) for bicycle manufacturing can be done in several ways. I have found some phrases and words that can give us ideas on what to search to read about the different methods or techniques available to get a permanent join of two pieces. These phrases are:

• Autogenous welding of bicycle frames (soldadura autógena).
• Oxy welding of bicycle frames.
• Oxy propane fillet brazing of bicycle frames.
• Brazing of bicycle frames.

I know very little about welding, so I had to search and read first to know what is available. The objective is to learn about the different methods for joining tubes for bicycle manufacturing. The first I have to understand seems to be the difference between Brazing (there is TIG brazing), soldering and welding (there is TIG welding). They are different.

Weigth of some Brompton bicycle models:

• M3L - 11.5 kg
• M3L-X - 10.5 kg
• S2L - 10.7 kg
• S2L-X - 9.8 kg
• P6R - 12.4 kg
• P6R-X - 11.5 kg

References

(zendesk.com, 2018): https://brompton.zendesk.com/hc/en-us/articles/203295301-Why-are-Brompton-frame-parts-brazed-

(lucasmilhaupt.com, 2018): https://www.lucasmilhaupt.com/en-US/brazingfundamentals/brazingvssoldering/

ASM Handbook - Volume 06A: welding fundamentals and processes.