26 replies to this topic

[wjames]

hi folks

just a simple one here.

i'll shortly be making some fair sized rockets(amongst other things), with a small payload of simple stars, and a flash report.......

I plan to make them a good 3 weeks prior to the big day.

is there any major issues with the flash de-composing, be coming unstable....or worse.... the fuel becoming far less reactive.......

i'll be using a simple flash for these - 50:50 Potassium Nitrate : Magnesium

it'll be about 1-2 grams in a fairly small tube(sealed both ends), with bp fuse delay...

I presume alot has to do with how humid the air is when i make the mixture ??? and how "dry" the tube is....

any advise welcome


im also hoping to make a devil amongst the tailors too - any advice welcome.....its hard to find clear information on these "old" fireworks.

for the centre mine, im planning to use small tubes ( same diam as a drinks straw )(different lengths) filled with bp for lift, and .2g of flash at the top.....im hoping to get a nice effect from these........anyone made these before ??

[Bonny]

The general concensus that I have read is to not store flash at all. Make only what you need.

[portfire]

Bonny's right. The cakes, mines I've made where I want a report, I'll do all the prep work first.i.e roll the tubes well in advance to ensure there fully dry, then prepare time fuse and finally when I'm ready to load a cake for example, I'll mix the flash, finish insert and load. The cake, mine etc will not be stood for any longer than 2 days after that if It contains Flash. Prep work IS the key here IMO.

Stay Safe and Stay Green.....You'll keep your hands!!

[phildunford]

A few issues here.

Ideally, store anything explosive for as short a time as possible.

Back in the real world commercial fireworks with flash could potentially be in storage for a couple of years, never heard of them not working.

I've no experience of KNO3 /Mg flash. Think it could well degrade if the Mg is not protected, esp. if there is any damp in the atmosphere. 70/30 perc/Al seems pretty stable in my experience.

BTW, my contructional details for a d.a.t.t. are here
Devil

for what it's worth...

[wjames]

yeah, i completly agree with storing flash prior to use........there's no need to make it, and leave it on a shelf....perhaps you miss-understood what i meant.

im talking about it being stored IN a finished product.....ie...contained in its tube, in the shell, and attached to the rocket body.


I could, i suppose, pre-make everything apart from the flash reports...and do the final build on the morning of the fire......BUT....i hate doing things that late....as if time becomes an issue.....Well...what im saying is i don't want to be rushing things last minute...thats how accidents happen !

i know there is an issue with rapid decomposition of chlorate based flash powders...with exothermic reactions and possible combustion....i guess what im basically asking is to confirm that KN03/Mg based flash powders don't suffer from the same issues.

I don't use sulfur in any of my flash powders.....my KN03/mg flash is powerfull enough as it is, and i don't see the point in adding something which makes it even more sensitive, when its not really needed.....

[YT2095]

have you added Boric Acid?
you Should if it`s a Nitrate/Metal comp.

[wjames]

Phil.....exactly what i was after.....thank you kindly.......after a look around, i see you had a go at the old clarks giant.....

always fancied making one of these......i saw one that was graded once....by that i mean there was about 10 different effects in it, it started off as a smoke flare, then went into sparks of various types(looked like Ti, mg/al, then iron), then changed colour a few times, followed by a few whistles, then the nozzle came out, and it turned into a free for all !!!!!


think i might make a scaled down version, i have a 3 inch dia 4 foot card tube here, from a carpet shop.....its about 2cm walled thickness. i'll make a few adjustments to the tube first.....think 2cm wall thickness will be ok ???? there's an huge amount of heat invloved....

[Creepin_pyro]

have you added Boric Acid?
you Should if it`s a Nitrate/Metal comp.

This is incorrect.

Quote from Shimizu: "Magnesium is violently attacked by various kinds of acid and even by a weak acid, e.g. boric acid or acetic acid."

[maxman]

I dont think boric acid is any help with magnesium, quite the oppisite I beleive it attacks it! Personally I would not use magnesium at all!!! If you must then I should use it straight away. Can you not use something more stable like 70/30 standard industry flash? Better still organic flash (whistle mix)

[wjames]

see.......this is why i ask before i do things im not 110% on !!!! safety first.

Ive just re-organised ALL of my chems into better containers....i was reminded once again of the importance of wearing a good respirator when using very fine metal powders...i use a NATO s10 respirator with a chemical filter......500 g of 400mesh mag powder..i moved it from its old containter into a proper anti static sealed bottle..using a spoon and paper funnel....on an anti-static pad....

noticible MG dust in the air....not in my lungs thankfully......

and yes i do clean my filters out!


as always guys, i DO take all of your comments on board, and i DO appreciate advice from folks.

Edited by wjames, 10 October 2008 - 03:10 PM.

[portfire]

wjames- I didn't mean that you make the insert on the day, what I meant was that you have every thing ready and make the insert, finish your Firework 2 days before you fire it.

Boric Acid is only added to NO3/Al mixes, as maxman said I wouldn't add it to a mix containing Mg or MgAl for that matter.

As with ALL flash comps, you must treat them with respect. IMO even standard flash is not suitable for someone who is really just starting out. If you must have flash I would go for KNO3/S/Al + 1-2% boric acid. Having said that, I'm no expert, but have found that KNO3/S/Al flash is (IMO) the mix to go for.....Thats the only flash I've used and I haven't made alot either....Much more interesting effects

[wjames]

"starting out"

i know what you mean....

ive learned an HUGE amount in the past 6 months, and still consider myself a beginner......

BUT, i am very carefull, and think before i act...i carefully plan everything i do, and consider the risks prior to doing anything. i wear decent safety gear. when mixing flash, i always do it in a different area from any other chemicals i may have. i only dispense the correct amount of chems i need...and when i do make flash, i make no more than i need in any one batch......if i spill any, ( which i have once) i stop what im doing. remove any components that may have flash on them, and clean up properly, including disposing any unused flash properly. only after a proper clear up, do i restart. by proper i mean a full wipe down, floor swept up, change of overalls, clean my boots......

i'll be making 10 rockets, and i'll be mixing flash 10 times.....2 grams at a time, and every time i mix, i'll be anti-static, earthed, and be using clean tools every time...

i think the way i approach making flash, is as safe as its going to get......someone told me once that earthing any tools is a good plan ( from a mains earth.....) anyone do that ?
i would use bp for my report, but i want to keep the weight down as much as possible, and gain a nice height....i also much prefer the sharp report you get from flash, when compared with bp......also, my flash doesnt need to be anywhere near as confined as bp to get a very loud report....and with using MG, its very very bright.


sorry if we are getting away from the topic as such....but there is some very good points coming across here !!!!


oh, and while we are at it, i don't have a ball mill yet....so my BP isnt the best.....great for rockets though.....

ive ordered isoprop for M+P - so i can get it that little bit finer, prior to ricing........but the isoprop is taking ages to come....any decent substitues....meths ? 151 proof rum ?

[portfire]

Please don't think I was having a "dig" when I said you where just starting out and wanting to make flash. You have obviously shown that you are very safety consious, which is a thumbs up in my books considering some of the 's we get one here LOL

Regarding making the salutes, have a look through this thread, theres my tutorial on Z cakes, but you'll want the part about making the Ti salutes

http://www.pyrosocie.......c=3743&st=0

[wjames]

i didnt think you were having a dig mate, its just as a "begginer" when i mention flash...the instant response from some people is "oh, you can't do that untill you've been doing pyro for 350 years !!!"

i think it depends on how safety consious the person in question is......i consider myself safe......

ive only ever had one serious accident in relation to any "science" experiments.....it was part of a tesla coil experiment....although i was building a "marx generator" using a 25kv LOPT as a power supply......it was all going well until the insulation broke down....and the nearest thing that was related to earth was ME !!!!

luckily, it was fairly low current by the time it got to me, due to the spark gap's i was using........it still hurt, picked me up of my feet and threw me across the workshop !!!!

[maxman]

Lol, switch it off before you mix the flash! hehe