Jerry Hey wrote:

I finally found the heat color charts which I had not looked at in
years.  My memory was incorrect.  According to the color guide the
piece of 304 was heated to approx 2000 degrees when  it started to
flake.  304 is said to be tolerant of temps up to 1400 F which is a
cherry.

  If you observe  your exhaust system at night is is easy to determine
the temps reached  by comparing the colors to a  chart.  A downloadable
chart can be found at  http://www.viratsteels.com/colorchart.html. The
temperature of the exhaust tubes will be much lower than the EGT.
Luckily, just looking at them with chart in  hand will tell you what
you need to know.  Caution, if  you try this in bright light, you will
not be able to distinguish the color variations adequately.

If you observe any part of your system hotter than 1400 F,  either go
to a heavier material or to Inconal.

BTW,  the system will not slowly get hotter and  hotter.  A few minutes
exposure to peak EGT and it will be as hot as it is going to
get.-------Jerry

 
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