Thermite or dipped igniters for reliably igniting 4 29mm I205's?

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BKNO3 I'll have to keep in mind for the future. Sensitized thermite I've done some some work with but it really makes me nervous. Ematch sets the hellfire off really easily. Other thing is I've heard some very careful and skilled fliers have
been really burned by it in spite of dealing with it with caution. Kurt
 
Hey, sorry for reviving an old thread, but those that are familiar:

Is BKNO3 regulated by the BATFE? I know most igniters are kind of in the grey area - the explosives list clearly says igniters are on the list, yet somehow some many commercial igniters aren't regulated. It also mentions "potassium nitrate explosive mixture," but I'm not sure if that counts?
 
To burn right the boron needs to be amorphous. Crystalline requires too much energy and temperature to break down structure.
Last price I saw was about a buck a gram.
 
Not if you ask for an "engineering sample". Kerr-McGee sent me a pound this way.

Not sure how that's possible seeing that they're no longer in business as Kerr-McGee.

What size is it? And what color is the powder? That will tell you if it's useful for igniters or not.
 
Yeah, with the price of B being what it is I'd only use it for a staging igniter/"starter" as I've been told it works well there. I'll remind this is the open forum so no recipes please. Kurt
 
Not sure how that's possible seeing that they're no longer in business as Kerr-McGee.

What size is it? And what color is the powder? That will tell you if it's useful for igniters or not.

Yeah, this was back in the late 90's when I worked at OU School of Industrial Engineering. I called up K-M because they are local. I was just looking for a couple of ounces. The guy sent me a pound, gratis, without my asking. It's 2 micron amorphous, dark brown and low density, almost fluffy. I used it in several pyrotechnic mixtures (gram amount or less of total comp.). We also tried a few experiments with it when I worked in Chemical Engineering. We made aerogel that contained it, and tried functionalizing the ends of carbon nanotubes with it.
 
Do not use thermite in a tiny 29mm motor. My 4-29SS flew just fine (two motors on pad and two airstarted) with the grains painted with QuickDip. If you are really worried, move to blue motors for the airstarts.

From the Ether...
 
Do not use thermite in a tiny 29mm motor. My 4-29SS flew just fine (two motors on pad and two airstarted) with the grains painted with QuickDip. If you are really worried, move to blue motors for the airstarts.

From the Ether...

Did you use ematch start for the airstarted, quickdip painted motors? Sensitized thermite can do it but I was lucky I didn't cook myself ground experimenting
with it. I didn't have any close calls but read more about the stuff after I had done some mixing and testing. Did some open air testing and my gosh there can
be a lot of heat.

The deal with thermite is using the right reagents and I'd suggest a knowledgeable mentor if one can be had nearby. I will share "right" means using an appropriate
"mesh" size otherwise thermite can burn really fast and give the appearance of a high order explosion. Precisely what one wants to avoid when starting a motor.
Again for the neophyte, don't blindly experiment and use somebody who's done it. Kurt
 
Did you use ematch start for the airstarted, quickdip painted motors? Sensitized thermite can do it but I was lucky I didn't cook myself ground experimenting
with it. I didn't have any close calls but read more about the stuff after I had done some mixing and testing. Did some open air testing and my gosh there can
be a lot of heat.

The deal with thermite is using the right reagents and I'd suggest a knowledgeable mentor if one can be had nearby. I will share "right" means using an appropriate
"mesh" size otherwise thermite can burn really fast and give the appearance of a high order explosion. Precisely what one wants to avoid when starting a motor.
Again for the neophyte, don't blindly experiment and use somebody who's done it. Kurt
Yes, I should have clarified, dipped e-matches for airstarts. In fact, as I think about it, every airstart I have done, 29mm thru 75mm has been the same painted grains, dipped e-match combo. I have only used "borrowed" thermite once for a 3" hole drag race.

From the Ether...
 
Yeah, this was back in the late 90's when I worked at OU School of Industrial Engineering. I called up K-M because they are local. I was just looking for a couple of ounces. The guy sent me a pound, gratis, without my asking. It's 2 micron amorphous, dark brown and low density, almost fluffy. I used it in several pyrotechnic mixtures (gram amount or less of total comp.). We also tried a few experiments with it when I worked in Chemical Engineering. We made aerogel that contained it, and tried functionalizing the ends of carbon nanotubes with it.

That's the right stuff. Not available to mere mortals these days.
 
That's the right stuff. Not available to mere mortals these days.

And that explains why they gave Dan so much of it. They were trying to score a big hit with the Engineering School he worked for. Nothing wrong with that. A Joe Blow wouldn't have been as lucky.
Ol' Dan now should realize just how lucky he was! I wonder if he has any left! Kurt
 
mixed our own BKNO3, but it's granular not pelletized. Anybody know suppliers for BKNO3 pellets? NOT granules aka Firefox, which we already have
 
mixed our own BKNO3, but it's granular not pelletized. Anybody know suppliers for BKNO3 pellets? NOT granules aka Firefox, which we already have

I use Viton as the binder instead of NC lacquer. It can be thinned with acetone and dipped, or molded into shapes, or pressed into pellets.

See the igniter thread in the research forum.
 
mixed our own BKNO3, but it's granular not pelletized. Anybody know suppliers for BKNO3 pellets? NOT granules aka Firefox, which we already have

We spoke about this & I mention using a "pill press" for making pellets with the Firefox stuff. I make mine that way, any type of "star press' works well. Fireworks pyro's use them for making "stars" in the large motor type fireworks.
1 gram size are largest usually used. I lit P motors with 1gram pellet as recommended by CTI [Jeroen] He actually supplied that one and hence forth I've made my own.

DSCN4826.jpg

First attempt are on right.
Now I get consistent ones like on left. Dampen granules with acetone & weigh on scale [1.5gram for me damp...after they dry completely 48hrs mine weigh 1.1g] place mix in pellet press and insert in vice crank down, remove. I coat mine with flexible nitro cellulose...hence the crusty look.



Here is a direct source for military grade pellets. {how I size mine}
Look at bottom for contact info good luck. I believe you must buy 1lb minimum. approx 450.00 or about 1.00 @ pellet. You may get off with some freebies for college experiments... never hurts to ask. If you have the Firefox stuff, it's not that hard to make them.

View attachment boron pellet copy.pdf
https://pyrotechnicspecialties.com/pyrotechnic-powders/
We discussed most of this at great length few weeks ago, but i don't think you had any BKNO3 at the time.
If you wish to further discuss "how to" call me. You should still have my #....if not PM me for it... I still have yours if you wish me to correspond.

If you have the granules....that's the exact stuff used to make the pellets [with out the binder] they use polyester resin binder with various additives depending on size & use.
.To make them correctly, you need to make large batches due to such small amount of binder 4.5% So I forgo all that & just compress and coat mine.

I am fortunate in that I acquired several lbs. before all the shipping kurfuffle .
 
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