[RocketsNW] IGNITERS

Thu Apr 9 20:23:46 PDT 2009

We had a chat about this somewhere, we figured core volume would be a better
way to determine amount. Can't remember if we ever decided what that amount
per core value was. 

Scott T. Bowers
www.scottsrockets.com

-----Original Message-----
From: Marty2 [mailto:MartyWeiser at comcast.net] 
Sent: Thursday, April 09, 2009 8:01 PM
To: 'Carl Degner'; scott at scottsrockets.com; 'Rockets NW list'
Subject: RE: [RocketsNW] IGNITERS

Carl,

The formula I was given by Wedge was 1 gram of thermite per 1000 N-s of
motor. It lit the 2nd stage of my M-to-M instantly.  Unfortunately, I had
forgotten to reprogram the timer which included about 1s for the motor to
come up to pressure.  Live and learn.

Marty

-----Original Message-----
From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
On Behalf Of Carl Degner
Sent: Thursday, April 09, 2009 5:14 PM
To: scott at scottsrockets.com; Rockets NW list
Subject: Re: [RocketsNW] IGNITERS

I once saw a link to a site that had recommended amount of CuO thermite to
use with different size motors.  It was a dead link.  Does anyone know of a
similiar site that can provide a basis for the amount to use?

Carl

> From: scott at scottsrockets.com
> To: lawndart.robert at gmail.com; bphlat234 at comcast.net; 
> rockets at rocketsnw.com; jhadv at pacifier.com
> Date: Thu, 9 Apr 2009 17:08:17 -0700
> Subject: Re: [RocketsNW] IGNITERS
> 
> One word...
> 
> Copper oxide thermite.
> 
> Wait, that's three words. Cheap, easy, safe, and works VERY well.
> 
> Crap, that's seven words, unless these words count, then....never mind. 
> 
> 
> Scott T. Bowers
> www.scottsrockets.com
> 
> 
> -----Original Message-----
> From: rockets-bounces at rocketsnw.com
> [mailto:rockets-bounces at rocketsnw.com]
> On Behalf Of Robert Krausert
> Sent: Thursday, April 09, 2009 3:39 PM
> To: Gary Harris; rockets at rocketsnw.com; Paul Bogdanich
> Subject: Re: [RocketsNW] IGNITERS
> 
> I'd like an opinion here. For 38mm and larger, I've been more 
> successful adding a sliver of Blue Thunder to the ignitor. I simply 
> take a grain of BT, and cut a chunk out and use kite string to secure 
> it
to the ignitor head.
> When I've done this, all motors have started fine. My question is, is 
> adding the BT sliver really helping, or would the large ignitor with 
> pyrogen have been fine alone?
> 
> Curious.
> 
> Cheers,
> Robert
> 
> 
> ----- Original Message -----
> From: "Gary Harris" <bphlat234 at comcast.net>
> To: <rockets at rocketsnw.com>; "Paul Bogdanich" <jhadv at pacifier.com>
> Sent: Thursday, April 09, 2009 3:06 PM
> Subject: Re: [RocketsNW] IGNITERS
> 
> 
> > Paul gave me one of his low-pressure and high heat producing 
> > thermite ignitors mentioned below last october to use in a 11-year 
> > old J350. It started up instantly like an Estes motor.
> >
> > Gary Harris
> >
> > ----- Original Message -----
> > From: "Paul Bogdanich" <jhadv at pacifier.com>
> > To: <rockets at rocketsnw.com>
> > Sent: Tuesday, April 07, 2009 12:30 PM
> > Subject: [RocketsNW] IGNITERS
> >
> >
> >> At 11:27 AM 4/7/2009 -0700, you wrote: "...there's likely no basis 
> >> for regulating an ignitor which is used with a non-explosive device.
> >> Igniters
> >> packaged with unregulated motors (and replacement ignitors) were 
> >> themselves considered unregulated."
> >>
> >> I think you said it in your e-mail when you said igniters, 
> >> "packaged with unregulated motors..." The only problem being that 
> >> said devices are, in the opinion of some, very low performance 
> >> devices so much so as to be just barely functional. People of this 
> >> opinion would point to all the chuffing and recycling one witnesses 
> >> at almost any launch. Such devices (total calorific output of less 
> >> than .5 kcal) probably do qualify as "motor starters" and may very 
> >> well be able to be unregulated. I certainly don't see why they 
> >> should be regulated as some safety match heads with the pyrogen 
> >> scraped off, dissolved in a solvent and cast around a bridge wire 
> >> would produce more heat. We don't regulate books of matches do we?
> >> I myself, however, would like to see an "igniter" that can add 
> >> between 6 and 10 calories per cc of propellant surface, generate 
> >> enough gas products to put the motor interior at >= 200 psi but < 
> >> 400 psi, totally burn well within 100 ms, and achieve a flux rate 
> >> of greater than 100 cal/cm2/sec for a 38mm motor (this last metric 
> >> can change with motor size and propellant characteristics). That's 
> >> an igniter and I think you're still going to need a permit for 
> >> those. A NASA Standard would be an example of such an igniter 
> >> albeit for a much larger motor than a 38mm.
> >> Whether or not a thermite (where such term includes thermate and
> >> thermalite) based igniters should be restricted is an open question 
> >> as those lie between the two classes of devices already mentioned 
> >> (they generally do not pre-pressure the motor nor create a shock 
> >> wave). I suspect however, that the BATFE position would be that 
> >> thermite, thermate and thermalite are definitely regulated as they 
> >> are included in the definitions section of the statute whereas APCP 
> >> was
not.
> >>
> >> _______________________________________________
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> >>
> >
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