13 replies to this topic

[ken]

i tried the 70/30 potassium perchlorate aluminum powder mix and it was very hard to light and didnt even light with visco fuse. does anybody know whats wrong with it?

[MMMMMM Pyro]

Hi, With all due respect, how long have you been into pyrotechnics, if the answer is much less than a year, you probably shouldn't be trying to make flash anyway...
With that said, there could be a plethora of things wrong with it, to name but a few:
KClO4 Particle size and the shape/mesh of your Al.

Stay green, {ALWAYS wanted to say that}

Mike

[ken]

i know what im doing and it was very small amounts of flash powder,

[MMMMMM Pyro]

Fair Enough,
In which case, maybe we can be of some assistance; what mesh/shape was the Al, how much flash were you trying to light and what was the particle size of the KClO4?

Regards,

Mike

[ken]

the al powder was 350 mesh and i dont know about the KClO4. i know the al powder should be finer but i at least expected it to burn like black powder

[MMMMMM Pyro]

350mesh, probably atomised?
When I first attempted flash I used the same and got hardly any burning at all... it may help to ball mill your perc and, possibly to use a little bit of {sulphurless} B.P. as an 'initiator'.

Regards,

Mike

[ken]

what about just sulphur (i know adding sulphur to flash is dangerous but if it hardly ignites without it with it it should ignite fine)

[shadowpyro]

Well The KClO4 should be as fine as possible, i.e consistency somewhere along the lines of flour.
350 mesh Al is not fine enough to create flash with KClO4, as its just far too coarse.
You could try ballmilling it with stainless steel BBs for a good few days and give it a try.
Where did you get this Al powder from? ebay or something?
Do you have any idea what the particle shape of the Al might be?

[ken]

shadow pyro, did you mean ball milling the al powder or potassium perchlorate?

[Mumbles]

Ball milling both materials would be ideal. Seperately of course. I do believe he primarily meant the Al. It would at least flatten the particles out somewhat giving a much higher surface area, as well as break up the particles to a smaller size once they are in a flake particle.

[MMMMMM Pyro]

I believe that Shadow was refering to milling the Al. This process makes the Al particles flake shaped which increases the surface area of each particle increasing its reactivity.
With regards to adding S, you could, but I personally wouldn't want to risk it...

Regards,

Mike

Edited by MMMMMM Pyro, 24 January 2007 - 08:29 PM.

[ken]

thanks for all the advise people.

[MMMMMM Pyro]

Not a problem! Let us know how you get on...

Regards,

Mike

[karlfoxman]

Closed! This has been answered in detail, you should not be making flash! If you cant make it light then your knowlage is low and you should not be making it.