Kurt,
Have you ever personally witnessed, or have a link to information about, a container of pyrogen dip ( for rocketry ) exploding when the lid was unscrewed ?
What pyrogen formula were you using that could be set of with a blow from a hammer ?
What information do you have about people being killed by a rocketry igniter ?
Please provide links . . . Thanks !
Dave F.
Dave no,
We're talking about two different things here. Pyrogen for high current motor igniters are not an issue here. I wipe the threads of the bottle and the inside of a cap and will store it for a time with impunity.
The first fire pyrogen for an EMATCH is very friction and shock sensitive. I think Dr. Terry McCreary and other sources have commented on that. There is a second pyrogen (in a classical ematch) that goes over the first dip. That one is not so shock sensitive. Unscrewing the cap of a first fire ematch dip that has dried on the glass or plastic threads and metal cap could provide enough friction to ignite the dried material on the threads and cap.
Whether or not the liquid in the bottle would go up I don't know.
Again, I am talking about ematch first dip not motor igniter dip.
Storing mixed motor dip in a liquid state for a time is safely possible with care.
Pyrogens for motor starters and ematches are two different animals.
Again, the pyrogen for motor starters/igniters is not all that shock sensitive. One wants a motor starter to flare, create high heat and not go bang. An ematch that "pops" works fine starting 4F charges although I did have a batch that flared nicely in deployment altimeter testing mode.
I believe the reason one doesn't hear horror stories of ematch mixing mishaps is there are not very many out there who make them from scratch. Chuck above mentions he's made them. Motor starters/igniters are a different story in that many folks can make them safely as the pyrogens (except for a few) are readily workable and safe for a hobbyist to make. More storable too.
Is that clearer now? Ematches and motor starters are two different animals here. No, I've never heard of anyone having a bottle of first fire EMATCH pyrogen go off in their face on one hand. On the other hand I'd expect they'd be too embarrassed to mention that online. As I mentioned, I used a hammer and lightly tapping the dried mixing toothpick results in a pop.
I will confess a Stupidhead moment as I one time had a Testor's paint bottle of dried out first fire EMATCH pyrogen and pondered what to do to dispose of it. I have a large woods behind my house and collect dead branches to burn to keep the area tidy. I still have to look out there and my wife (now deceased) wanted the area to be kept clean. I agreed. I did a bonfire of tree branches and nonchalantly tossed the bottle of first fire EMATCH pyrogen in. After a few seconds there was a WHAM! and the bottle fragments come flying out fortunately out toward the woods and not towards me! I was smart enough to run away after I tossed the bottle in and was a fair distance away.
The next small bottle of dried out first fire pyrogen I had I stuffed a standard rocket motor igniter in and buried it into the ground with a large rock on top of it. Pushed the button on my 12V launch system and nary a pop. Dug it up and disposed of the glass fragments. One gets smarter with experience.
Kurt Savegnago