That bad word again..... FLASH!

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sparky
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That bad word again..... FLASH!

Post by sparky »

Hey all

Yes I know the risks and I'm not obsessed with booms but every now and again I need to make good ol, basic 7:3 flash.

I actually don't like making it, even though I work very safely it still gives me the heebie jeebies but that is besides the point.

So I have my finely ground KP powder in one pile and my german dark in another (or whatever your Al type of choice is at the time) and I diaper away to my heart's content with a nice big sheet of paper.

However, I can't help noticing that some of my recently powdered KP is clumping and if I prod it with a wooden dowel I see it break up further. The more I delicately prod the more I realise this is not well integrated at all. I'm definitely not about to push this lot through a sieve and there's only so much poking about with a wooden skewer I can be doing with.

To be fair it still does the job for me if I need a little booster or even the odd salute. I've never noticed that they lack much in the way of boom. But it is bugging me....so do people ever add any cabosil or graphite etc to the KP and screen it before diapering?
Cheers

Sparky
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

I'm definitely not about to push this lot through a sieve and there's only so much poking about with a wooden skewer I can be doing with.

To be fair it still does the job for me if I need a little booster or even the odd salute. I've never noticed that they lack much in the way of boom. But it is bugging me....so do people ever add any cabosil or graphite etc to the KP and screen it before diapering?
---------------
You're cursed with "the British Isles"! Wet is as wet does.

Oven-dry or 'chamber dry' those materials before use, and re-screen them right ONTO the diapering paper, aluminum first, the perc second.

Start diapering as soon as the last grain hits the paper. You won't get that clumping phenomenon, if you're fast enough.

And yes... 0.5% Cab-O-Sil will help, but must be milled into the perc to be particularly useful.

But, for what it's worth -- gently shaking 7:3 through a 20-mesh screen won't endanger you. It's when you bang the screen, rub your nails against it, or try to force comp through that doesn't wish to go, that you encourage problems. Simply shaking a screen side-to-side doesn't incur any of that risk.

Lloyd
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sambo
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Re: That bad word again..... FLASH!

Post by sambo »

definitely agree - add the cabosil, and also agree 0.5% milled in works for me !
Paul Moulder
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Re: That bad word again..... FLASH!

Post by Paul Moulder »

Try just adding around 10% rice hulls or sawdust before diapering it and you should find your clumping problems go away.
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

Paul,
Are you suggesting that Monsoon in Thailand is wet?

Lloyd
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sparky
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Re: That bad word again..... FLASH!

Post by sparky »

Cheers guys. I always feel slightly lazy when I post questions like these as I've seen some of these suggestions before but I like the advice I get in here and I hope people like the fact it's fresher and also I personally feel I can trust it more.

My set up may limit my ability to get things really dry before I diaper, I know I have trouble milling too as I often get that annoying ball of partly milled BP form. I'll try a touch of cabosil and the rice hull ideas.

Lloyd - About the idea of screening the flash composition. I suspect I am being overly paranoid about the stuff but that is not a bad thing with flash I suppose. When I am just basic screening to ensure a already finely milled powder is not clumping I tend to use a kitchen sieve. I have a cheap plastic one and a cheap metal one (probably chrome) which I guess are about 20 - 40 mesh, I tend to reserve my home made wooden framed screens for screening "grades" of charcoal and making sure stuff I buy is the mesh I want. Do you think an all plastic or all metal sieve is a static hazard?

I'm always grounded and only wear cotton when I work with super dry, finely milled comps like this and milled BP comps, especially ones that use the faster charcoals.

From what I've read static sparking is mainly a problem with flammable vapours but also fine dust and what bugs me about sieving flash is that for a time it is falling as a fine powder.
Cheers

Sparky
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

From what I've read static sparking is mainly a problem with flammable vapours but also fine dust and what bugs me about sieving flash is that for a time it is falling as a fine powder.
------------
Sparky...
Static doesn't just "happen somewhere". It's NOT going to happen in a cloud of (even conductive) dust, unless there is a potential difference across that cloud.

The BEST screen for screening any pyrotechnic composition is a flat, metal screen mounted in a wood frame, with NO metal fasteners (except brass or aluminum) exposed (and preferably not those). When screening compositions, one does not rub, but 'shakes' the composition side-to-side in the screen.

If the table, the paper, the screen and the operator are at the same potential (that is bonded or grounded), no sparks will (nor even CAN) occur from static.

IF your relative humidity is above 65% and you have first touched and 'discharged' yourself to your work table before starting, there's very little chance of any static forming, much less discharging.

I understand that in the UK, a relative humidity of 65% is considered "desert conditions"! <G>

Lloyd
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Paul Moulder
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Re: That bad word again..... FLASH!

Post by Paul Moulder »

Lloyd wrote:Paul,
Are you suggesting that Monsoon in Thailand is wet?

Lloyd
Humidity here is almost never lower than 80% so static risks are pretty low.
The monsoon season is coming to an end this month thank God and we are now entering the 'winter' season when I begin to feel a little nesh :) A cool 28 to 30 is a typical winters day here, summer is over 90% humidity and 34 to 40 degrees. After 20 years here I've got used to the heat and wouldn't swop it for a winter in blighty.

On the topic of mixing flash, I realy don't care for screen mixing and believe it entails a lot more risk than diapering, having said that I can see the advantage if you need to mix 10 kg at a time in a commercial setting. I firmly believe daipering is not for babies and use it to mix up to 5 kg batches with peace of mind.
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

"...I firmly believe daipering is not for babies and use it to mix up to 5 kg batches with peace of mind..."
0000000
I've never liked the phrase "diapering is for babies"! I've always felt it was an insult to those who must use it on some materials.

I have one particular 'hyper-flash' I will not screen -- diaper ONLY. It contains sub-micron-sized perchlorate, sub-micron antimony sulfide, sub-micron magnesium, AND additional 'sensitizers' to increase its explosivity. It's for the purpose of creating small UN-contained reports in the 1/4-gram range of mass for close-proximity effects.

7:3 is many dozens of times LESS sensitive to friction and impact than this stuff.

Lloyd
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Paul Moulder
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Re: That bad word again..... FLASH!

Post by Paul Moulder »

"...I firmly believe daipering is not for babies and use it to mix up to 5 kg batches with peace of mind..."
0000000
I've never liked the phrase "diapering is for babies"! I've always felt it was an insult to those who must use it on some materials.


Yes I agree with you 110% Lloyd, the term suggests someone using diapering is in some way a wimp and as such could cause them not to use what is perhaps the safest mixing method available to us.
where did the expression come from ? I've seen it a few times on Passfire and Fireworking
sparky
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Re: That bad word again..... FLASH!

Post by sparky »

Paul Moulder wrote:"...I firmly believe daipering is not for babies and use it to mix up to 5 kg batches with peace of mind..."
0000000
I've never liked the phrase "diapering is for babies"! I've always felt it was an insult to those who must use it on some materials.


Yes I agree with you 110% Lloyd, the term suggests someone using diapering is in some way a wimp and as such could cause them not to use what is perhaps the safest mixing method available to us.
where did the expression come from ? I've seen it a few times on Passfire and Fireworking
It's an american expression to do with babies nappies. I think it is due to the partial folding shape you make with the paper as you mix it. If you ever used old towel nappies you'd know exactly what I mean lol.
Cheers

Sparky
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

No, Sparky, actually, it comes from ONE specific pyrotechnician, whom I will not name.

He is imminently qualified to lecture any pyro you could name on almost any technique you could name -- but he has this 'thing' about diapering flash. He somehow considers it to be a fearful and stupid thing to do; and he's not a stupid man.

Go Fig'!

Lloyd
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sparky
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Re: That bad word again..... FLASH!

Post by sparky »

Lloyd wrote:No, Sparky, actually, it comes from ONE specific pyrotechnician, whom I will not name.

He is imminently qualified to lecture any pyro you could name on almost any technique you could name -- but he has this 'thing' about diapering flash. He somehow considers it to be a fearful and stupid thing to do; and he's not a stupid man.

Go Fig'!

Lloyd
Well there you go. Clearly he didn't visit that illegal M-80 making workshop out in the US where 11 people got blown to bits. I'm fairly sure they weren't diapering ;-)

Forensics couldn't make much out of it....
Cheers

Sparky
dave321
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Re: That bad word again..... FLASH!

Post by dave321 »

Lloyd wrote:"...

I have one particular 'hyper-flash' I will not screen -- diaper ONLY. It contains sub-micron-sized perchlorate, sub-micron antimony sulfide, sub-micron magnesium, AND additional 'sensitizers' to increase its explosivity. It's for the purpose of creating small UN-contained reports in the 1/4-gram range of mass for close-proximity effects.

7:3 is many dozens of times LESS sensitive to friction and impact than this stuff.

Lloyd
that sounds real scary stuff lloyd :o
Jolyon
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Re: That bad word again..... FLASH!

Post by Jolyon »

what percentage kp is used in flash compositions generaly as i cant find 100 anywhere
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

What is this "100" you cannot find? I'm not aware of any component of flash called "100".

I'm sorry -- You just asked for the formula for flash, and that really runs some warning flags up the pole around here.

Anyone who asks that question has never spent even a minute reading any pyro literature. That makes you dangerous to yourself and to our hobby.

Lloyd
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Boophoenix
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Re: That bad word again..... FLASH!

Post by Boophoenix »

sparky wrote:
Well there you go. Clearly he didn't visit that illegal M-80 making workshop out in the US where 11 people got blown to bits. I'm fairly sure they weren't diapering ;-)

Forensics couldn't make much out of it....
That location is only a few hundred km from me. I remember it being in the news vaguely when I was younger.

Like Sparky I have a very healthy respect for it. I currently haven't really had much call to need to ever use it for myself. I have used it a couple of times at other places.
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Pyro-Gear
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Re: That bad word again..... FLASH!

Post by Pyro-Gear »

Jolyon wrote:what percentage kp is used in flash compositions generaly as i cant find 100 anywhere
Lloyd just about summed that up FP is a subject we don’t really need to discuss, you really need to get some literature on the subject, sure as Lloyd said it waves a red flag.
Jolyon
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Re: That bad word again..... FLASH!

Post by Jolyon »

hello,this is an attempt to put people at ease, my former post was not put together very well in hindsight and thus i understand the general response, i'm not asking the composition to make fp ive read my fair share on it but i was more asking a question on kp generally as to what percentage in terms of purity people have found and use across there pyro creations.

many thanks and sorry for the concern caused, i can assure you i understand the dangers of fp and the concern of needing to discuss it

Jolyon
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

Jolyon,
Tech grade is more than pure-enough for all 'normal' pyro endeavors. The Chinese bulk material seldom assays at even the "tech" purity, and it's adequate for almost everything except delicate blues.

If you're intending to make a blue-tinted mixture, you might want to purchase some expensive reagent grade material.

I don't know of any pyro chemicals available in "100%" purity. That's nigh-impossible to attain, unless you're willing to pay $50/gram for chemically-pure lab samples.

But I must say -- your question makes it sound as if you have access only to mixtures of oxidizer/inerts that have LARGE quantities of adulterants in them. I've not heard of such on this side of the ocean. What "percentage purity" were you discussing?

Lloyd
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richardh08
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Re: That bad word again..... FLASH!

Post by richardh08 »

Lloyd wrote:If you're intending to make a blue-tinted mixture, you might want to purchase some expensive reagent grade material.
Or you could consider recrystallising it. KP is sufficiently insoluble in cold water that the process is very efficient. One or two recrystallisations can reduce any sodium contamination to insignificant levels.
Even when I'm wrong, I'm convincing.
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Pyro-Gear
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Re: That bad word again..... FLASH!

Post by Pyro-Gear »

As far as I am aware KP that is available in the UK originated from two suppliers one from Spain and one from Brazil both products contain some sodium, if you are after the perfect blue then recrystallization is recommended.
Tyvole
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Re: That bad word again..... FLASH!

Post by Tyvole »

My supply from central Europe also contained enough sodium to mess up blues but was fine for everything else. It claimed 99.2% KClO4 and only 0.2% NaClO4. Following Richard's guidance, I recrystallised a small amount for use in the blues. It was a bit of a tedious process, but not difficult.
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Tom Schroeder
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Re: That bad word again..... FLASH!

Post by Tom Schroeder »

Boophoenix wrote:
sparky wrote:
Well there you go. Clearly he didn't visit that illegal M-80 making workshop out in the US where 11 people got blown to bits. I'm fairly sure they weren't diapering ;-)

Forensics couldn't make much out of it....
Actually there was testimony from a former employee. Flash was mixed in a 5 gallon bucket with an electric drill and a paint stirrer. They had operated for several years before the explosion!

Tom
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

"Flash was mixed in a 5 gallon bucket with an electric drill and a paint stirrer."
0-0
<Shudder!>
L
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Tom Schroeder
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Re: That bad word again..... FLASH!

Post by Tom Schroeder »

Lloyd wrote:"Flash was mixed in a 5 gallon bucket with an electric drill and a paint stirrer."
0-0
<Shudder!>
L
https://en.m.wikipedia.org/wiki/Benton_ ... s_disaster

It's on Wikipedia.

Tom
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Lloyd
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Re: That bad word again..... FLASH!

Post by Lloyd »

Yes, Tom. I have read that accounting of the accident several times.

Each time, I pale at the thought! (while they apparently "pailed" at the thought! <grin>)

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Boophoenix
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Re: That bad word again..... FLASH!

Post by Boophoenix »

Lloyd, as you'd say we lack a few branches in this area, lol.
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