Brazing Tab Type Dropouts

[Ahmdo Molah]

E4DA654C-F921-45A6-83A5-81D1FF000A36.jpg

If you shove 1/2 a 1/16th" bronze rod evenly into one of those joints, it's all good.

- Garro.

Thanks for your pointer Steve. I'm using coiled 1/16" Gas Flux C-04 wire, measure cut and straightened to a rod's equivalent length, then splitting these standard rod lengths in half for each side of the tab, instead of using one continuous rod throughout the process, as this allowed me to keep track of how much got 'shoved' in per side(i.e. If I flipped the joint, I'd use the designated half rod for the current top side).

Therefore, in my samples above, I've been 'shoving' in twice as much as what you and John have advised(!). Oh dear... But of course my samples are mock-ups, not real chainstays(nor dropouts), so the cavity may be larger.

I was aiming to fill according to the Paterek Manual (as suggested in the drawing on p. 2-46 "Braze filled" Dropout Joint), with a bowl shaped internal fillet and a full fill all the way out to the opening of the joint.

Paterek Manual (Brazed Dropout Joints).jpg

The depth(length) of fill is not clearly defined in the drawing, so I assumed that the base of the bowl shaped internal fillet should start near or at the internal edge of the dropout (as is shown in the 'Simple braze' drawing).

In your joints and that of Eric's, the filler is not "topped off" to the very edge of the tube's half-moon openings. I assume this is because the strongest tensile strength is at and near the slots where the gap between the materials is least, and that the larger gap of the cavity is comparably of secondary concern, perhaps one more of aesthetic preference(?).