test shell 2" video

[superspike23]

hi

 

I tested six shell tonight. I have seen your comments at all. I think I've progressed. But I have a new problem. My stars do not ignite. here's the video:

 

http://www.youtube.com/watch?v=Z4XIfiZ59vU

[deadman]

What kind of break, stars, and prime did these shells have?

[ryanlg95]

I can't currently watch the video, but are you aware that stars usually need to be primed? I don't need to prime my tigertail stars, I don't know about anyone else. I'm pretty sure that stars that use blackpowder chemicals (KNO3, S, C) don't or USUALLY dont need prime because of their similarity to black powder, therefore easy to ignite. but you can't go wrong by priming your stars just in case to prevent them blowing blind. If your stars are already made, just use a sprayer to spray 75:25 Water/Alcohol (methylated spirits works fine) on the stars and sprinkle meal blackpowder on them and allow them to dry. If making fresh stars, after they are pumped or cut (I doubt you'd be rolling them) while they are still damp just sprinkle some black powder on the stars.

-Ryan

[taiwanluthiers]

Also have a 1mm layer of prime too, not just a dusting of primes... gemstone stars (emerald green, ruby red) can get away without primes but should be primed anyways. Perchlorate stars (veline, etc.) must be primed with at least 1mm layer of bp+metal (silicon works well) prime to light properly. Chlorate stars will light without a prime but it must be primed to provide a barrier against the sulfur in black powder unless everything else in that shell is either made from chlorates or perchlorates (like KP or H3), and even then it should be primed with something without sulfur.

[Seymour]

"gemstone stars (emerald green, ruby red) can get away without primes but should be primed anyways. Perchlorate stars (veline, etc.) must be primed with at least 1mm layer of bp+metal (silicon works well) prime to light properly"

 

I have serious issues with the factuality of what you are saying about high MgAl Barium and Strontium nitrate coloured stars. What you are saying is true of many Potassium nitrate based stars, but the fact that these formulas also have a nitrate oxidiser and Charcoal, Sulfur and Dextrin in them does not mean they behave anything like my old friend Tigertail, (which as you pointed out, should be primed anyway).

 

If it were not for the charcoal and sulfur in it I would fairly comfortably state that I expect Ruby Red and Emerald Green will be harder to light than your average perchlorate colour, and even with these ignition aids, I would describe them as pretty normal for 'modern standard Potassium perchlorate' coloured stars in terms of ignitability.

 

I hear fairly regularly that people are having trouble lighting Barium nitrate based greens using primes that work for their other colours. If I put unprimed stars of a purple KP (CuO and SrCO3 as colourants) and Barium nitrate greens in the gentlest ignition conditions commonly encountered by stars, like starmines, and poka - horsetail - dumped with a little BP on top of a rocket, I would expect some purple stars to light, but would be surprised by any greens that did the same.

 

With the dangers involved in the subject matter on APC and other similar places, Misinformation does potentially present quite a risk. While it's normal to beg readers to cross reference anything they read before believing it true, people do take things on face value too often.

 

In this case the misinformation was no more dangerous than to risk someones shell blowing stars blind, but it's frustrating nevertheless.

[superspike23]

to break these shells, I used the same as granulated powder for lift.

 

the composition of stars:

 

red:

 

nitrate strontium 50g

mg/al 63um 18g

parlon 16g

red gum 10g

 

 

dusted powder meal

 

and green:

 

 

Barium nitrate 56

Red gum 7

magnalium -200 mesh 17

PVC 15

Dextrin 5

 

dusted powder meal too

[Seymour]

Your priming is your problem. Need more, and hotter.

 

Ultimately step priming is pretty normal for high MgAl KP and nitrate colours. While Silicon in a greenmix type mix works wonders, it is a bit of a luxury.

 

A first step of KP, Resin, charcoal and some metal (MgAl or fine Al) is generally used to light the star mix, and this is primed with semi decent greenmix or lower quuality BP (you actually want the lower quality stuff here because it's a prime... fast and clean burn is not what you want.