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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 12-06-10, 02:52 AM   #1
bleedingapple
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building a fillet part 2?

ok so i am practicing my brazing and stuff though i have a question about getting those nice built up fillets you see sometimes... I was trying to add more material but it wasnt building up... should I let it cool and add more or coll fully clean re-flux and build up from there?
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Old 12-06-10, 04:51 AM   #2
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Not a completely simple answer. I have tried three models. It is possible to keep building, you shouldn't have to stop cool, clean, and reflux. But if you have a bad result that could be what you had to do. I remember this thread where someone took a course and they where tought to build stalagmites of brass, rising up say a foot or more, to learn the appropriate heat control to build a stack that didn't slump. Flux will keep running off in this method and it gets scooped back into place with the rod.

Another paradigm is to work webs in at the quarters, or less, and then capture the fillet in-between like filling a bowl. A variant is to place the fillet on one side, and just keep rotating the joint to place more material in the pocket on one side.

I work mostly with silver and for the most part cause those fillets to simply place themselves with surface tension and they have hardly any radius at all.
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Old 12-06-10, 07:08 AM   #3
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Good brazing technique involves a lot of factors. I'll mention some basic ones here. First position your 2 tubes to be in a V with both sides at an equal angle so when the brass melts it runs into the valley. You control brass by keeping it in the mushy temperature state between being liquid and solid. If you heat it just a nanosecond too long it will run away. This need for precise control is why you use compact hand motions (newbies tend to move their hands way too much). I prefer to lift my rod slightly off of the puddle. Most likely your rod and flame should be at roughly a 45 angle to the work. The most dominate method of heat control (there are a number that influence) is by flicking the flame on and off the puddle. If you were to watch Herbie or me demonstrate in class it doesn’t look like we are moving either hand all that much. When you have filled the valley you need to move the joint so as to always keep the puddle on top.
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