21 replies to this topic

[jermain]

I'm having a few issues with making small amounts of flash powder.

First of all, I'm completely aware of how dangerous FP is and taking the necessary safety methods, I've started by only making 2g amounts at one time so if it does go up in my face it would hopefully not cause to much damage.

Anyway the problem has been completely the opposite, my FP is incredibly slow reacting. First of it is incredibly hard to get going, as i understand it FP should ignite instantly, not with me, I struggle to get it going even by placing the 2g batch on top of newspaper and then setting the whole newspaper on fire. Even this struggles to set it off, once it does start reacting it of course is very bright but can take up to 10 seconds to burn through 2 grams!!! It reminds me of when I first tried making BP with a pestle and mortar and how slow burning that was.

I am currently using a 70:30 potassium perchlorate to aluminium powder mix and using the standard way of mixing (that being on a piece of a4 paper, can't remember what the method is called). I ensure that the compound is fully mixed before testing so that cannot be the issue. After the first couple of poor reactions I tried ball milling some of the KCl04 but this had little effect. I have even tried using some of my potassium nitrate stock to see if it was poor KCl04, but I could not get this to even light.

The KCl04 and aluminium powder I ordered from hobby chemicals (could it be that these chemicals are not v.gd?)

Any help would be appreciated.

Thanks

[maxman]

What is the particle size of the aluminium powder?

Maxman

[digger]

Right then.

A few obvious questions and recommendations.

1.) Buy yourself some fuse so that you can test it properly.
2.) have you passed the perc through a fine mesh sieve to break up and clumps.
3.) Most importantly is it the right type of aluminium powder, If you are using standard spherical powder such as 250 - 400 mesh then it will not work. You need a good quality flake aluminium, any German or Indian will do. It is easy to tell the difference between flake and spherical as the spherical will pour easily and not leave dark smudges when rubbed between your fingers whereas the flake will feel greasy and stick to any surface that it is rubbed on.

edit, I see you beat me to it Maxman

Edited by digger, 01 July 2011 - 10:37 AM.

[Karl]

Just to echo what has previously been said, you need to use Dark Aluminium; Indian Blackhead, German Eckhart etc. From the way you describe the reaction your using 200# mesh Aluminum.

[jermain]

Right then.

A few obvious questions and recommendations.

1.) Buy yourself some fuse so that you can test it properly.
2.) have you passed the perc through a fine mesh sieve to break up and clumps.
3.) Most importantly is it the right type of aluminium powder, If you are using standard spherical powder such as 250 - 400 mesh then it will not work. You need a good quality flake aluminium, any German or Indian will do. It is easy to tell the difference between flake and spherical as the spherical will pour easily and not leave dark smudges when rubbed between your fingers whereas the flake will feel greasy and stick to any surface that it is rubbed on.

edit, I see you beat me to it Maxman

First of all thanks to everyone's replies.

1). I have 25metres of visco fuse which i use, it doesnt set it off.
2). yes i passed it through 2 sieves, one fine, one very fine, this is after it had been milled
3). I think this is were I have fallen down. I have been using Al powder of 400 mesh.

http://hobbychemical...t&product_id=56

This one to be precise. Looks like I will need to order some more aluminium. On the plus side, looks like we have found the reason!

Thanks again.

Edited by jermain, 01 July 2011 - 02:07 PM.

[jermain]

This Al powder correct?

http://hobbychemical...t&product_id=55

Or perhaps one of these?

http://www.cooperman...p?cPath=77_3_31

Can't help but notice the price difference btw (more expensive than normal Al), anyone know the reason for this? Just curious. Manufacturing process longer/harder perhaps?

Thanks

Edited by jermain, 01 July 2011 - 02:07 PM.

[Karl]

This is the one you need ; http://www.cooperman...08l2kfharl51br5

I can't stress enough that if you need chems, goto Cooperman's site. I had problems with formulas after buying sheite off eBay but haven't had any since using his stuff.

Not sure on the price, maybe the manufacturing process or difficulty in sourcing it makes it more expensive?

[starseeker]

I have just looked on the hobbychem site,i think they are taking the micky,£17.99 for 250g of eckhart dark ali

[Karl]

Tell me about it, I know flash isn't cheap but jeez you'd have to re-mortgage at those prices!

[MDH]

With all due respect, we can't possibly help you unless you are to provide exact specifications on all of the chemical and material grades you are using. I agree with most of what has been said here, except that you "need" a very high grade of aluminum powder - an uncoated -200 mesh flake powder will suffice with proper containment.

If your aluminum appears to be extremely shiny, I'd be interested in knowing if it has a "greasy" smell. Paint grade aluminum is coated with various waxes or oils for endurance purposes, and is useful only for fountains and stars.

[PyroCreationZ]

Wow, hobbychems is bloody expensive
I'd never buy there.

I've bought many times from cooperman (and chatted alot with him) and I can only suggest you buy from him.
His chems are very good quality (high grade) and he has one of the best prices in the UK.
The dark pyro is the one you want and when it comes to making flash you'd want the finest mesh possible. I personally have both Indian & German dark (eckart), these are the best ones to use (2-5µ).
Indian is even better as it's usually finer then German dark + slightly cheaper (due to lower labour costs in India)

One important thing I'd like to say is make sure your pot perch is sufficiently milled!
First time I made flash (using German dark) I experienced the same thing. I used a butane torch and it just would not light!
Then I made a new batch but milling the pot perch much longer. Then mix it with German dark (diaper method obviously) and tested again: PHOOF! Instant bright flash with a nice thumping sound

Since it's the first time (?) you're making flash I'd like to suggest to use as many PPE as you can.
When I make flash I ALWAYS use:
- Chemical resistant gloves
- Respirator which stops both fine particles as well as fumes
- Face shield protection
- Anti static wrist wrap
- 100% cotton clothes
- Remove metal from your body (watch, piercings, rings, belt)

But I assume you already knew most/all of these safety rules

Oh one more thing, when testing, never use a normal lighter as your hand is way too close. Sounds obvious but I've seen people do this!
I personally use incense sticks (taped to an even longer stick) which works perfectly. This way your body is far away from any sparks.
Or you could use fuse but I consider it less safe (sparks flying around) then the incense sticks method + I like to use my fuse for projects and less for testing + incense sticks are cheap.
Some comps might be difficult to light with the incense sticks though but in those cases you can use fuse.

Edited by PyroCreationZ, 02 July 2011 - 10:32 AM.

[jermain]

Great post PyroCreationZ and thanks for all the information.

Having a look around hobbychemicals does seem to be incredibly expensive!!

Regarding PPE, i do indeed use most of the methods listed below except that I don't have a face mask and use safety goggles instead. I may invest in a face mask though if I start making large quantities of FP.

[Creepin_pyro]

.

Edited by Creepin_pyro, 20 September 2011 - 04:45 PM.

[digger]

Regarding PPE, i do indeed use most of the methods listed below except that I don't have a face mask and use safety goggles instead. I may invest in a face mask though if I start making large quantities of FP.

A face mask is of great use. As creepin says a it won't save you from any significant amount of flash. However it is great idea to prevent you breathing in chemicals when you are mixing them. Especially with fine powders that float around in the atmosphere easily like aluminium and K perchlorate.

I always wear a mask when mixing unless it is only a gram or two (with bright flake I would still wear a mask at a gram!, just getting it out of the tub turns everything silver).

[Mortartube]

Great post PyroCreationZ and thanks for all the information.

Having a look around hobbychemicals does seem to be incredibly expensive!!

Regarding PPE, i do indeed use most of the methods listed below except that I don't have a face mask and use safety goggles instead. I may invest in a face mask though if I start making large quantities of FP.

This is what I have and not much more cost than goggles

http://www.screwfix....browguard/22372