Firewall

On Sun, 15 Feb 2004 20:57:48 GMT, Orval Fairbairn
wrote:

:
:I have used a bandsaw with a smooth blade to friction cut titanium. One
:time I had a very small chip catch fire and burn itself out on the
:bandsaw table. I think that it takes a lot LESS than 5000 degF to flame
:it.

That may be true, but I'm trying to figure out how. Ti melts at
3020°F and boils at 5949°F.

I'm assuming that solid Ti doesn't burn - it's Ti gas that burns, just
like everything else. So, in order to release Ti gas, the solid has
to get to 5900 degrees. Even if it's just a little, tiny point on the
TI that gets that hot.

I've seen white hot Ti sparks coming off a grinding wheel. To be that
color, they've got to be up in the 3000 degree range or hotter.

I've put an old fashioned gasoline blow torch on a thin piece of Ti
and left it there for an hour. It glowed red and got surface
discoloration, but it didn't melt or burn through. The hottest point
in a blowtorch flame is 21-2200 F

BTW, the melting point of 304 stainless is 2590°F. I think if you
have a fire hot enough to ignite Ti, your stainless will be long gone
- along with the rest of the engine compartment.

richard riley wrote:

On Sun, 15 Feb 2004 20:57:48 GMT, Orval Fairbairn
wrote:

:
:I have used a bandsaw with a smooth blade to friction cut titanium. One
:time I had a very small chip catch fire and burn itself out on the
:bandsaw table. I think that it takes a lot LESS than 5000 degF to flame
:it.

That may be true, but I'm trying to figure out how. Ti melts at
3020°F and boils at 5949°F.


Well, friction cutting does imply that it is hot enough to melt.
Might a thin chip get enough concentrated heat to double the temp?