Need advice on bottom bracket repair

On 10/01/2017 4:13 PM, AMuzi wrote:
On 1/10/2017 1:52 PM, wrote:
On Tuesday, January 10, 2017 at 11:36:41 AM UTC-8, Benderthe.evilrobot
wrote:
"Jeff Liebermann" wrote in message
...
On Mon, 9 Jan 2017 22:24:41 -0000, "Benderthe.evilrobot"
wrote:

"Theodore Heise" wrote in message
...
On Sun, 08 Jan 2017 17:01:01 -0800,
Jeff Liebermann wrote:
On Sun, 08 Jan 2017 16:31:15 -0800, Jeff Liebermann

wrote:
(...)

Yet another untested idea...

Use an induction heater on the steel cup.
https://www.youtube.com/watch?v=MyZEaPQinO0
https://www.youtube.com/watch?v=YJElT9xK3bk
https://www.youtube.com/watch?v=uimEZKrVNO0
https://www.youtube.com/watch?v=3u1IBgefNDs [1]
http://www.theinductor.com
You'll need various size coils for different bolts, cups, seat
posts,
etc. There are induction heater kits on eBay:
http://www.ebay.com/itm/1000W-ZVS-Low-Voltage-Induction-Heating-Board-Module-Flyback-Heater-Brass-Coil-/282317713643

The steel cup gets hot and not so much the rest of the bicycle,
including the aluminum bottom bracket which sucks away much of the
heat. However, you can get the steel hot enough to melt the
aluminum,
so please use an IR thermometer to keep the temperatures down.
Aluminum melts at 660C.

Yikes!

Is there a problem?

An electric heat gun is safer than a blowtorch - but I think you still
have
to be a bit careful.

The heavy duty paint strippers aren't too bad, but some heat guns are
designed for lighting solid fuel cooking ranges.

The problem with external heat generators is that the heat affected
zone is rather large and will surely creep into undesirable areas,

A bigger problem is heating too small an area and causing the metal to
distort.

I'm sure that you've distorted many bottom brackets with a hair dryer.

and those really big curlers under a plastic cap...


With a burnt down lucky strike hanging off your lower lip.