48 replies to this topic

[EnigmaticBiker]

I have no doubt in my mind that flash powders are capable of undergoing detonation.

Watch the following video of an ISO container full of waterfalls (The composition of which is very similar to, if not less dangerous than flash powders) conducted by TNO Netherlands. The outcome was most unexpected.

http://www.chaf.info...rfalls_full.wmv

W W

That was amazing, spectacular demonstation of how properties change with confinement.

What must it have sounded like?

I'd be curious to know how far the sheet of metal, (disappearing off the left hand corner of the screen) went.

[BigBang]

Yes i agree, absolutely amazing WOW! Ive never seen that before. I never would have predicted that reaction in a million years.

Edited by BigBang, 18 September 2006 - 05:17 PM.

[Richard H]

See http://www.chaf.info for more spectacular test videos. The technical reports accompanying the tests make very interesting reading.

See http://www.chaf.info/d9-3-4.pdf

[Pretty green flames]

Very informative site Richard, thanks for providing the link.

And that video is amazing, reminds me of the enschede accident in Denmark.

[EnigmaticBiker]

See http://www.chaf.info for more spectacular test videos. The technical reports accompanying the tests make very interesting reading.

See http://www.chaf.info/d9-3-4.pdf

Before I saw that site, never thought I'd want to be a technician again.
The idea of carefully working out the worst possible disaster with fireworks and then being PAID to film it.

Wipes brow

(Even better than those sites featuring ladies doing various trouser activities from the waist down!)

What I find scary is the size of shrapnel and the distance it went.
On the video 60_rockets_full2.wmv, the time difference between sight and sound was about 1.1 s which (assuming the camera is with the mic and sound velocity at 345m/s) means that those large bits of steel container went over 380 metres.
Can't realistically assess the size of the fragments though.

Edited by EnigmaticBiker, 18 September 2006 - 07:30 PM.

[BrightStar]

I believe that Perc / Benzoate whistle mix might well detonate in small quantities with relatively little confinement. My 'research' involved about 10g of whistle in an HDPE plastic pot, spiked with string. This was fired on a long wire and so was relatively safe, but I was frankly shocked by the result.... Be careful please.

As an afterthought though, and as a humble junior member, may I suggest that we try to keep this forum 'clean'. While accident reports are important, photos of dismembered torsos of kids playing with pipe b**mbs are probably not. We have all submitted our credentials to be members of this group and try our best to work safely. I for one don't want to feed the anti-fireworks lobby with evidence of others' bad behavior.

Edited by BrightStar, 24 October 2006 - 07:05 PM.

[BigBang]

Brightstar...i hear what you are saying, but sometimes it is necessary to shock people into listening. You can use words to warn people until you are blue in the face, but they wont listen. If they actually SEE for themselves the consequenses of irresponsible behaviour, the message might just get through. This is the very reason i filmed the flash powder in action. Hopefully, it may just save someone from ending up like the people in those pictures.

[karlfoxman]

Very right Andy, I believe this is the best aproach! Lost count of how many times i've told people not to play with it. You have my backing here!

[BrightStar]

Just to clarify here, I'm half in favour of the Coke can demo as a deterrent. I saw Ron Lancaster of Kimbolton do something similar INSIDE a lecture theatre in the Phys Chem labs in Oxford with about 0.5g of flash in a small card tube - it shredded into minute flakes in front of a stunned audience.

My hesitation was more with Creepin's link to human casualty pics (particularly the bottom photo) which I really wish I hadn't seen. I'm just not sure they are fully relevent to our work on this forum, for the reasons mentioned above. Yes, they are factually correct and of note, but I'm not convinced this kind of stuff improves the outside preception of the forum.

As I say, just my personal opinion...

Edited by BrightStar, 19 September 2006 - 06:27 PM.

[karlfoxman]

Sure, but some people will now be too scared to play with it seeing what can happen. That link is part of a pyrotechnic composition database.

[portfire]

i agree, using shock tactics to deter people is sometimes the best way to get the message across. dont think i'll ever be playing with it

[fishy1]

I haven't used it before, but I will be pretty soon. It's one of the last things I have to try that I'm curious about. I've worked with some pretty energetic comps, but not Flake Al/Perc flash.

After seeing that video, I have to say I'll be even more careful than I was going to be. I'm now probably going to make it up in batches up to 5g max, and to use substitutes where possible. In any case, I'm not making any large salutes with it. I'm only ordering enough flake for about 200g flash anyways.

[BigBang]

I wasnt sure whether to film and post a video like that, but after the positive response, im glad i did.

Ive had a fair few people say that they are going to stay away from flash after seeing that video. The general feedback ive had is........"i heard that flash is dangerous, but i never realised it was that powerful, i certainly wont be using it" so ive achieved exactly what i intended to achieve.

Im sure there are some idiots out there who still wont listen, but i guess they have to find out the hard way.

[adamw]

Just a sneaky mention of our up-coming convention at which I will present a piece on safety.


Hope to see you all there!

[fishy1]

What comp was that flash btw?