On Thu, 4 Jun 2015 07:47:39 -0700 (PDT), rangerssuck
wrote:
On Thursday, June 4, 2015 at 8:06:17 AM UTC-4, John B. wrote:
It is easy to do,
just paint the area with a marker - permanent or white board - and
then heat the area with a torch until the marker goes away.
Interesting - i'd never heard of using a marker as a heat indicator. Any idea what temperature that "vanishing point" would indicate?
I've always used these: http://www.tempil.com/products/tempilstik-original/
I don't know the temperature for markers, but this is a variation on
the method used in aluminum bodywork for most of a century.
If you have to work out a dent, you strip the paint, like you would
with steel bodywork, and then you take your O/A torch and light it
with no oxygen. You then play the sooty flame over the aluminum,
giving it a thin coat of soot.
You then turn on the oxygen and heat the aluminum until the soot just
burns off. This is something typically done with a rosebud torch.
It's not very accurate, but it's good enough to anneal the aluminum
sifficiently to work it with a hammer and dolly -- or a slapper and
dolly, more typically with aluminum.
--
Ed Huntress