Brazing Tab Type Dropouts

[steve garro]

4094293_orig.jpg

Thanks for your pointer Steve.

OK - so, a little build history will go a long way here - if you look at many (almost all) mass produced road bikes of the brazing era you will see what's often called a "domed stay" where it's rounded at the dropout end and the dropout just snugs in there - how do they shove in 1/2 a rod you wonder?

They don't.
They just 'lipstick' the edges around the end of the stay, maybe feed a bit more in at the back of the DO and on you go to the next 1000 you have to do that day and they last just fine!

Also, no need to cut it apart to see where the bronze is - just look at the dark cherry colored plug as it cools slower than the rest of the stay - this is the extent of your fill - indeed, many builders leave the stay 'lipsticked' around the edges of the slot and the end of the spearpoint is open to drain, no plug.........


- Garro.

[Ahmdo Molah]

... - indeed, many builders leave the stay 'lipsticked' around the edges of the slot and the end of the spearpoint is open to drain, no plug.........

Would a cross-section view of such "no plug" stay look something like this*?
(*without the bent rod stand)

No.15 (Cross Section, No Plug).jpg

[steve garro]

Would a cross-section view of such "no plug" stay look something like this*?
(*without the bent rod stand)

No.15 (Cross Section, No Plug).jpg

Yep.
That is every bit as strong for the same reason tubing is hollow !!

- Garro.

[Ahmdo Molah]

Yep.
That is every bit as strong for the same reason tubing is hollow !!

Thanks so much for the confirmation and explanations... it has broadened my understanding and perspective on options.

... It appears you got your joint too hot. ...

Once I turned OFF the very bright overhead lamp*, and used a much dimmer light** off to one side, I could see the red glow of the metal much sooner with much more range of tones (much of which was masked with the brighter light ON).
*(2400 lumen 30W LED strip, equivalent to about 2 x 100W incandescent bulbs!) vs
**(900 lumen 10W LED strip, equivalent to about 1 x 60W incandescent bulb)

This made it much easier to make a significant reduction in heat input. Enough that the mock-up sample went from looking like a

Warty Sea Squirt (tasty seafood delicacy btw, LOL)

Warty Sea Squirt.jpg

to one that looks more like a braze joint!

No.16 (Brazed Without Overhead Lamp).jpg

I now understand why many builders' shops are dim.

Pulling the flame(away from the work) also helped significantly in keeping a steady glow while working. Thanks again for the tip!

[Andrew R Stewart]

When I lived in Raleigh NC my brazing location was outside on the patio. I got a white "event" tent with sides to cut done the breezes. If the sun was out the tent was so bright that I couldn't see the heat/colors until things were really hot and the flux was burning. Someone suggested watching the flux changes as the heat level indicator and that worked for me. Now my shop is in the basement (and no longer in NC) and the brightness is far less but I still look at the flux as the initial heat indicator. Andy

[Ahmdo Molah]

Mr. Paul Brodie has just uploaded (3 hours ago) a nice video of him replacing the chainstays on a vintage Ritchey frame.
Fast forwarding to 16:12 ~ 18:52, there's a nice filtered close-up view of him brazing (filling in) the 'half moon cavity' with some pointers to boot!

[claritycycler]

Thanks for posting this. Paul Brodie's vids are the best!

[Ahmdo Molah]

Indeed, watching Mr. Brodie's videos reminds me as a kid blown away by Bob Ross! : O ?!

Good to see he's gained some weight back after his chemo treatments. Best of health to him...