Bicycle manufacture.

For those who so enjoyed the last video I posted, this one's pretty
good too.

http://www.youtube.com/watch?v=u94WsKf6JRo

--
Paul - xxx

On 31 Mar 2011 21:51:03 GMT
"Paul - xxx" wrote:

For those who so enjoyed the last video I posted, this one's pretty
good too.

http://www.youtube.com/watch?v=u94WsKf6JRo

That's painful to watch, he's just struggling to get enough heat into
the work. I laughed when he said to keep the flame moving - he had to
hold it still just to get the solder to melt. I've only brazed frames
using oxyacetylene, but if I were to do one now as a home builder I'd
be more inclined to try a propane burner in a hearth than a Mapp torch,
especially after seeing that.

Rob Morley wrote:

On 31 Mar 2011 21:51:03 GMT
"Paul - xxx" wrote:

For those who so enjoyed the last video I posted, this one's pretty
good too.

http://www.youtube.com/watch?v=u94WsKf6JRo

That's painful to watch, he's just struggling to get enough heat into
the work. I laughed when he said to keep the flame moving - he had to
hold it still just to get the solder to melt. I've only brazed frames
using oxyacetylene, but if I were to do one now as a home builder I'd
be more inclined to try a propane burner in a hearth than a Mapp
torch, especially after seeing that.

Heh, glad it wasn't just me thinking that!

To be fair, the annotations do mention the limitations fo the low
temperatures, but to me that just says it's not 'the best' method for
joint manufacture.

--
Paul - xxx

On 1 Apr 2011 06:32:06 GMT
"Paul - xxx" wrote:

To be fair, the annotations do mention the limitations fo the low
temperatures, but to me that just says it's not 'the best' method for
joint manufacture.

It's not low temperature that's the problem - silver solder has a
working temperature around 700C and Mapp gas burns in air at about
2000C, and he pointed out an area where he'd burned the flux - it's just
the overall amount of heat that's delivered. Propane also burns in air
at about 2000C, but this bottom bracket is warm enough for brass brazing
http://bp3.blogger.com/_SZx2oaxuJSA/...agedFrame3.jpg
(working temperature around 900C) because he's using a big burner to
generate plenty of heat and a hearth to keep it where he wants it.