Thanks! I’m definitely doing a lot of re-melting and I see the bronze bubbling as I do this, but I thought it was from flux. Seems like fillet brazing is like welding and you only get one chance to lay down as perfect of a fillet as you can? I’ll have to keep practicing. I’m keeping things as clean as I can with Acetone and sanding but will be better about it.
I’m in the Boston area. I love the idea of finding real mentorship but will be busy with the day job for the next year or so.
Appreciate the advice from everyone, I’ll be back to share future practice pieces.
The other part of this (frankly the bigger problem) is the power tools hitting the tubing. That’s a big no-no. I think Brodie does a little disservice to everyone who isn’t in his class by showing how he finishes fillets (after hundreds of frames).
Use an appropriately sized round file, don’t let it touch the tube and then use 80grit shop roll to finish. Put the power tools down and slowly back away. Seriously, a nice fillet needs almost no clean up (says the guy who spent his day finishing fillets!).
This weekend I was finally able to set up my torch, and to do my first bits of bronze-brazing. I tried building an icicle (inspired by Paul Brodie), as well as doing one tube-to-tube join (without trying to get a perfect fillet, it was just to get some feel for the process.)
The tip of the icicle formed some sort of lump, that would not accept any further bronze. Does this mean it got too hot? And on the other picture, you can see some copper-colored sections in the “fillet”. Is this something to worry about?
I cut it open, penetration looked good. I also tried to break it, but the section I brazed onto the bigger one was too small and just bent. I will do more joins tomorrow, to see how strong these small fillets really are.
The problems you are seeing are exhausted flux and too much heat. Just do more joints like that and then clean it up and lay a fillet on top.
Edit: It is a good long-term goal to make some fillets in one pass, but I made my first three fillet brazed frames by making a first pass to focus on penetration, then a second to lay the fillet. It is easier to control the heat once the two pieces are joined, cleaned up, and re-fluxed.
Seriously, a nice fillet needs almost no clean up (says the guy who spent his day finishing fillets!).
