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I need to stamp the frame number too.
001?
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I think fillet brazing has some similarities to TIG, having used both to build frames. When I fillet braze a frame I'm using a pretty small torch nozzle (normally a #2, sometimes a #3 with a neutral flame inner cone of around 4mm) and 2mm SIF 101 rod.
I don't like putting massive fillets down. Smaller ones are mechanically strong enough to have a joint that exceeds the tube strength, plus your minimising the total amount of heat, the HAZ, and reducing distortion.
I'd definitely recommend playing around with practice tubing to see how getting right in close with a smaller Oxy Acetylene flame works.
It's not quite the same as stacking dimes when you TIG, but with the right settings you can get a similar result with a fillet braze.
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Scilly.Suffolk
Mikenetic
@Brommers
OK, a belated update. Needless to say, I'm not still doing the course. That finished at lunchtime on the Friday. We were all fairly eager to get away early on the Friday, me in particular, as I wanted to get round the north-western quadrant of the M25 before the rush hour started in earnest, and because Casa Danstuff needed some serious remedial tidying before @Cycliste flew in for the weekend.
By Friday morning the frames were basically finished apart from some filing on the lugs just to tidy up the shorelines and some polishing. @Cycliste bought me some rather nice riffler and engineer's files for Christmas, and I've got plenty of emery tape at home, so I was quite happy to leave the filing and polishing until I got home. However, both Josh and I were keen to try a bit of fillet brazing before we left.
So, after a quick demonstration from Geoff, we fired up the torches and started our first efforts at fillet brazing. This is my first attempt:
I spent too long doing it, as the tube on the right was quite distorted. I need to learn to use a bigger flame, get in, do the brazing, and get out rather than spending lots of time fannying around with a small flame. It's pretty rough, so I didn't spend too much time tidying it up, but I did give it a quick file and polish when I got home so that it looked like this:
Since then I've done a bit of filing and polishing, but nothing particularly photogenic. I've got the paint to spray the frame, but I need to finish off the design for the vinyl decals so that the nice people at Enigma can cut them for me. In the meantime, I've been collecting parts. This bike's going to have mudguards, so I've built it for long-reach brake calipers, and I finally managed to source some VO Grand Cru calipers in black.
I've also got the fork, which is a Columbus Hiver. It's got mudguard fittings but is still reasonably light at 400g claimed (actually 412g on my scales). It'll be painted to match the frame.
So, vinyl decals to design and then it's time to get painting. I'll take some photos of the frame when I've finally finished the polishing and filing. Oh, and I need to stamp the frame number too.