[RocketsNW] Subject: Re: IGNITERS

[Paul Bogdanich]

	I have also looked at MnO2 - Al thermite as opposed to CuO based 
thermite.  While MnO2 - Al is definitely hotter than CuO - Al 
thermite,  MnO2 - Al thermite displays rapid expansion characteristics that 
can be confused with explosive as the reaction temperature is above the 
boiling point of both Aluminum and Al2O3 so it throws its toys from the 
pram as they say.  Straight MnO2 - Mg thermite is something I have not 
tried but by the math the predicted heat of reaction should be 
materially  higher, the gas production much reduced and the expansion 
minimal due to the high boiling point of MgO.  But as with many things 
concerning fine Mg it's probably not safe for some obscure reason.  I was 
most surprised to learn for example that an uncured NH4ClO4 - Mg mix 
develops an exothermic potential to the point of a serious risk of 
spontaneous ignition if there is any water or water vapor around.  Not 
good.  So I try and avoid Mg whenever possible.  That's probably why it's 
nearly impossible to get Mg to the point it can only be shipped LTL.