No, no not fillet brazing - 'bronze welding'! It is used in the consruction of motorcycle tubed frames, and race car tubular body structures. It's a lower than weld heat technique, but it isn't brazing, much stronger from what little I've discovered about the technique, than braze but not as strong as weld, but the lower temperature technique, hopefully shouldn't have any further detrimental affect on the previously TIG welded parts that it needs to attach to. I've been welding for over 25 years and I had to google it!
They are now offering me that (with 853 in the repair), and a single colour repaint with a two year warranty on the work, or the frame I don't like/want and continue the lifetime warranty or £300. I'll almost certainly take one option, unfortunately £300 isn't going to get me anything I like - I've checked. I quite liked my old Thorn....guess I'm leaning that way at the moment but not decided yet.
Its the same technic
You can really make a comparison with TIG and brazing. Some tubes like the Fat chance true temper for example, were made for TIG. When you weld it, you make a heat tretment too of the metal. But If you have to repair it, you loose the treatment.
On other hand, for more classic steel, brazing is enough.
But, I didn't know the 853. But a lot of reynolds tubes are lugged or brazed. So…
Well… it's really not acceptable…