Question on mixing flash safely and shelf life

[RIP]

I've been using a flash mixture of 30% German Dark Aluminum and 70% Potassium Perchlorate. My questions are:
What methods do you guys recommend for mixing it safely? (I always get nervous when I mix the stuff...)
After mixing it and placing it in salutes, how long can this stuff last when well sealed?
How "shock sensitive" would the above mixture be?
I've read a few of the other flash posts, and this seems to be the safest mixture. Anyone recommend a safer mix, or do I have it?
Thanks much, RIP

[SafetyLast]

The mixture you are using is reasonably stable. More so than Chlorate based flash that is. I use the "diaper method" for mixing two powders. Take a sheet of newspaper and fold it lengthwise. Unfold it and fold it along its width. place 15g of Al powder on one end and 35g of KClO4 on the other end. lift up the ends of the newspaper and gently shake the powders into each other. Well sealed I would say it would last up to a year or longer. No need to store it for that long however. I wouldn't store it for more than a couple months. I can't speculate on the sensitivity since that is due to a large number of factors. It would be susceptible to the drop of a hammer.

[RIP]

Thanks very much. RIP

[Mumble]

I've never been able to acheive ignition from only a hammer strike. I've gotten it from sparks from the hammer, but never the strike itself. I feel I do an adequate job of mixing so this shouldn't be a problem. Overall this is one of the safer flash mixes. I've stored it for upwards of a year with little performance decrease, but I would not recomend this.

I indeed use the diaper method as well which works wonders. I've heard of people using very soft bristled painting brushes. They are the kind designed for small patterns. I don't know where they would carry them exactly, but craft stores are a good bet. I'm not to keen on the idea, but it is a plausible. If you could get cotton bristled I think it would be ok. Definatly don't get natural hair or polyester bristles.

[10fingers]

That diaper method is crap. Put about 30 grams in a small plastic bottle, like a vitamin container. Put the lid on and then duct tape the bottle to the end of a long piece of pvc pipe and then spin it around for awhile. Make sure that when you open the bottle that you don't have a static charge on you.

[GreenCoat]

I like John Donner's method in "A Professional's Guide to Pyrotechnics: Understanding and Making Exploding Fireworks":

1) Powder the KClO4 and run it through a 40 mesh sieve
2) Add 0.5% Cab-O-Sil (fumed silica dust), mix and again through 40 mesh sieve
3) Place mix on to kraft or other suitable paper
4) Add the aluminum powder
5) Raise each corner of the paper successively ('diaper method') until mix appears homogenous
6) Run mix through a brass 30 mesh sieve twice

I would not store it for long as, even with the Cab-O-Sil there may be some caking of the mix. Probably no more than a couple of months.

[Joeychemist]

I don’t like the "diaper method" either, like 10finger's said its crap. I use a deep porcelain bowl with straight walls and I hold it on a 45 degree angle while spinning the mix. (Just like a cement mixer) but I think the bottle on the end of some pipe or a broomstick idea is the best and safest one I’ve heard. That is a good idea 10fingers. :)

[hpy2bhre]

I use a quaker oatmeal container as its card board. I have it taped to a long pole and add my base then the metal powder tape the lid shut and spin and turn it untill its mixed well. I usually mix 100 grams in a batch then fill my shells. After 5 years of the same way of mixing I still get butterflys in my belly while mixing flash.

[Bert]

You can never be too safe. The various folks recommending diapering or mixing with a bristle brush are trying to keep you from doing something insane like mixing it with a ceramic mortar and pestle... and it will still work fairly well even if it's not perfectly mixed, obviously.

That being said, screen mixing AFTER pre-screening the ingredients separately is what every pyrotechnist I've known who actually has much knowledge or experience does. Rotating drum mixers are also used industrially, but a safe and proper setup of this type is a bit complicated and expensive. If you want to generate static electricity inside your flash mixing aparatus, by all means experiment with makeshift rotary mixers!

Shelf life? I've got devices from the 1950's made with perchlorate, Aluminum and Antimony sulfide that still work fine. If you're using Magnesium or magnalium you might
want to consider ball milling some Potassium dichromate with the perchlorate.

[RIP]

I appreciate all your help. I too get butterflies when making flash. I've been using a heavy pvc container with lid off, the same container that black powder is sold in. I weigh out the 70/30 right in the container, then rotate at a 45 degree angle. I make sure I'm not in contact with any items that could cause static to build up. Seems to work good. I do like the long stick addition. Perhaps I'll add that to the method. I think being in constant contact with the container would prevent a static discharge. Thanks again. RIP

[NiteRider13]

I see no mention of combining the Al and KClO4 in a Zip-lock bag, and spraying it with static guard. Then very carefully rotating the bag as to mix it all up. this is the method I use. Is this method wrong, or extremely dangerous? I don't like the Diaper method, because I feel that more powder remains on the newspaper than i would like to leave behind.

[anselmo]

I've used the Shimizu loudest report formula for decades.
Potassium perchlorate.............................64
Aluminum.......................................... 23
Sulfur............................................ 13

I always use the diaper method.

I start by putting fresh newspaper on my whole table. Set my scale and chemicals on one end, two more full page sheets of newspaper on top of each other on the other end.

On top of the two full sheets I set a 16 inch round Sona Tube, 6 inches high, with aluminum screen attached to the top of it.

Now days I spray everything with Static Guard. Every time I come up to the table, I touch a place where there is no powder first, just in case of static.

Respirator and rubber gloves. In the summer, I have a fan pulling the dust away from me, and out the building. I keep the dust down as much as possible. Indian Black Head is very good for no dust.

I start with the Perchlorate, put it through the screen, spreading it evenly, then the Aluminum...then Sulfur. A little more than a pound all together.

The Sulfur has been a pain in the ass many times. It clumps together easily.

I remove the screen and lift the corners of the top diaper newspaper several times till it looks uniform. I fold the paper together with the powder in the middle, lift it and put the screen on the second diaper newspaper. I pour the powder out around the top of the screen and push it through with a plastic Tupperware measure. Take the screen off and rediaper. Lift it and pour it into a plastic container.

15 pounds or so can easily be made in an hour.

Lately, I've been mixing 70/30. Seems to be the same...Awesome..put a small amount of Titanium before plugging and you get nice sparks.

I've seen the Shimizu formula boom big time after laying around in devices for over 3 years.

I started out with the little container on the end of a stick....huge pain in the ass.

[anselmo]

Small confined 70/30 with a tad of Titanium. Didn't see any sparks...trying to work the camera. At night they look good.

I probably missed the part with the sparks anyway. I'm surprised I got this. I took 4 pics with a Rebel.

In full res you can see red pieces. The biggest round piece could be a plug.

http://www.viol8r.com/guns/crackoff.JPG

[RIP]

Thanks much. I was actually thinking of titanium to make sparks. Perhaps larger chips? Anyone ever try adding aluminum chips or lathe shavings to the salutes? RIP

[Bert]

Tried large Al, didn't work. Tried adding coarse Mg turnings, no sparks but a much brighter flash as the Mg vapor air burned- Nothing behaves quite like Ti or Ferro Ti (except Zirconium, Hafnium or depleted Uranium... and they're even more expensive)

[al93535]

I always use the diaper method and it seems to mix everything quite nicely, 70/30. Although I only mix small 10 gram batches at a time. In my last salute, an 8 gram one, I used 20 mesh Ti, and got nice quick lived sparks. It was very nice to watch! I have also read that steel would work just as well, 20 mesh or so.

[Kingtaling]

The first thing I think about Ti is that its a sparking metal, I read somewhere that mixing it with flash is a huge mistake in that Ti can just spark on its own if shooken up-

I also read that screening the flash after you've already mixed the Al with the oxidizer is a bad idea, as its sensitivity to friction of going through the screen can set it off.

I just started making flash yesterday, so this is all new info stuck in my head. I mixed 10g last night for 2g in a total of 4 salutes (the last 2g being lost in spill or stuck the tissue paper) I used tissue paper to diaper mix it up (which did work fine, it was very well mixed in under 2 minutes) and it behaved very well in the salutes which I fired off today, each one sounding, at least to me, amazing and powerfull. FTR I used KClO4 and Dark Al from a company called "exchem" or "expedited chemicals" off ebay. I have several kinds of Al to experiment with, and I intend to, but his came in the mail first. I am also getting some German dark (from skylighter) and some of that 1250mesh atomized off ebay (which isnt supposed to work that well, but I wanted to try anyways) and some Al from pyroaluminum.com as well. Im going to have a... blast.

Ninja edit: Has anyone ever heard of anyone using 100% Tungsten metal in flash? It might sound crazy but strangelly enough I have a large supply of it.

[m-80]

I have been making flash powder for a long time and I always roll it back an forth on a sheet of newspaper, this method is used in industry and works very well if you do it properly. There is no need to screen the flash powder through any sized mesh because diapering is sufficient, and as it can be set off by friction (flowing through the mesh) and static (could pick up a static charge as it goes through the small holes) it just isn't clever.

Never mix more than 10 grams at a time. I have read that a lot of people mix over 10 grams and all I can say is it isn't a good idea at all. IF 10 grams is accidentally ignited it will explode and cause hearing damage and possibly a loss of fingers along with burns. On the other hand though, if say 30 grams is accidentally set off....the injuries could be very severe with total loss of hearing and missing hands ect...

Just to say that 0.1 gram of good quality flash powder makes a loud bang in a small 2mm tube. I have been testing flash powder recently and got that 0.1 gram result using very fine KCLO3 and 5 micron flake Al in a 7.2/2.8 ratio.

Adding Ti powder to flash powder increases the risks of an accidental ignition due to Ti's known sparking ability (work with less that 5 grams or so of flash if Ti is added). Adding Ti to a black powder rocket composition can also cause the mixture to ignite when ramming it into the casing.

[Bert]

Ti salutes are an item of commerce. The manufacturers would not make them if they were unacceptably dangerous. I have fired many Ti salutes at displays. They will take the shock of lifting out of a gun, rough handling in shipping & etc.

Anything that leads to friction or shock on flash mixes is obviously a bad idea. That being said, common industrial practice is screen mixing of perchlorate/Al flash, often in 10-12lb. batch size.

Why would you use tissue paper for diaper mixing flash? Smooth kraft paper or even notebook paper would serve better.

[m-80]

Mixing techniques change depending on the chemicals in the composition but I have heard that the diaper method is used with most flash mixtures as it is the safest method.
USE
If they make flash in batches as large as 10-12lb that is a serious amount of explosives to be putting through a fine mesh. Just a couple of grams will take fingers/hand off imagine what 12lb's would do.
PARAGRAPHS
I’m not saying flash powder will suddenly explode and kill you for no reason, but it will if your not careful and respectful when working with it! Just use common sense and treat it like a primary explosive and you will be OK.

[Bert]

Everyone who writes a book or article for new/hobbyist pyros will tell you to use the blanket method, or stir the chemicals on a piece of paper with a soft natural bristle brush, or similar extremely difficult to fuck up and kill yourself method suitable for making a small quantity of flash in a non production situation. I tell newbies the same thing- Use the safest way. And since we don't know if you're going to make KClO3/S/Mg or something even crazier, and have no idea how careful your manipulations will be, it is well to do so. However, you will not run a factory with these methods. If I had to treat flash mix as I would a primary, I certainly would never make and fire report shells or inserts.

I do NOT recommend that anyone, PARTICULARLY BEGINNERS do what we do. And that is:

Take 8 lb. of Potassium perchlorate and 1 lb. of black Antimony sulfide (or Sulfur) and 2 Oz. of Cabot M-4 Cab-O-Sil, screen them together through a 24" X 18" 40 mesh screen onto 3 lb. of dark Aluminum in a similar 20 mesh screen, sitting on a receiver box over a 3' X 3' piece of 80# virgin kraft paper. Any coarse crystals that can not be pushed through the 40 mesh are discarded.

My screens fit one into another, the receiver is a box with no top or bottom that the bottom screen sits on/fits into. This arrangement helps keep too much dust from flying about...

After the oxidizer and Sulfur or sulfide have been mixed by passing through the 40 mesh screen and are sitting on the Aluminum powder, the 40 mesh is set aside and not used for subsequent screenings of the entire batch. Only the coarser 20 mesh screen will be used. This makes it unlikely that excess friction/rubbing will be needed to get the mix through the screen, it should fall through with a very light stirring of the gloved hands (leather gloves, not plastic!)

The mix is gently screened through the 20 mesh, then the receiver and 20 mesh screen are picked up and set on a second square of 80# kraft. The square of kraft with the partially mixed flash is diapered one or two times, and then poured into the 20 mesh screen again. This operation is usually repeated 3 times, or until it is not possible to find different colored areas of the mix when you diaper. With experience, the whole operation takes perhaps 15 minutes including weighing the chemicals and putting the finished flash in storage containers.

We say that after the first pound, limiting the batch size is only done as a courtesy to the neighbors... You will probably be dead and dismembered if there is an accident with even a single pound of partially mixed flash. 12 lb. of flash is an amount I can comfortably handle, and will not tear the good quality kraft diapers. The same equipment and methods comfortably mix 12 to 20 lb. of color star mixes, depending on their density and my needs.

I have been doing this for 15 years. My teacher has been doing it since the 70's. His master did it for 40 + years, and died in bed. I use anti static, wear cotton clothes and choose high humidity days to work, the old boys just worked flash on humid, cool fall and spring days. Of course, a respirator and face shield and safety glasses are worn when mixing any chemicals.

In my experience, it is increasing the number of times the operation is carried out, not enlarging the size of the batch that most increases the danger- I would rather mix fewer, larger batches than more and smaller ones if I need a large amount of product.

Titanium IS NOT screened into the mix. It is either diapered into the completed mix or added directly to the salute caseing on top of the flash if it is not too full to be mixed by tumbling of the powder within the device in the course of stringing, paste wrapping & etc.

[Kingtaling]

I thought it was OK to mix up to about 40g of loose flash, so long as it was loose. Unconfined, up to (50g) is supposed to just deflag with a bright WHOOSH! not a bang or anything super-dangerous besides a bit of heat.

That said, I still limit myself to 25g at a time atm. I may try 35g eventually, but never more than 50g because of the risk of (critical) mass deflag.

[nbk2000]

Self-confining through the mass of the powder can cause d>D transition

The exact amount varies depending on the composition of the powder, but can be as little as a few grams..

[m-80]

Even 10 grams of a strong flash powder will explode in the open especially when using fine Mg powder. If a 50 gram pile of high performance flash containing Mg flake powder went off when you were close to it, it wouldn't be a pretty sight.

Just the other day I was testing some different ratios using 5 micron flake Al and KCLO3 and 2 grams of a comp containing less Al and more KCLO3 in the corner of a baking tray sounded like it was close to exploding when it ignited. It was maybe a little bit confined by the corner edges of the baking tray but not much.

I poured around 10 grams of KCLO3/Al flash into a 15cm long and 1.7cm ID plastic tube with hot melt glue to seal the ends. This was then wrapped in newspaper and trasported to the test site in the back of the car. When the destination was reached the plastic tube was then pushed into a copper tube and this device was then placed into a VCR. When the device went off there was a very loud explosion and the VCR was torn to tiny pieces and thrown 30 feet in the air.

That device was extremely loud and powerful and would have seriously hurt you if it went off in your hand, maybe even killed you. That was just 10 grams, remember the power of flash increases drastically as the amount used increases. It is also not a good idea to use any kind of metal container as a casing for any kind of exploding device because of shrapnel. I have a lot of experience and respect when working with flash powder devices otherwise I would not have dreamed of making any device with a metal casing.

[Bert]

It can be as little as a few tenths of a gram for mixes with very fine Mg powder. And that "bit of heat" is not to be trifled with either!

[Kingtaling]

Which is why I stick to the "safe" perchlorate mixtures ONLY!!!
I even tried hammering .5g of this stuff, it wouldnt go off. I stuck my hot glue gun in it and it didnt go off.
Im going to put it in a pan and heat it till it goes, so I can get an idea of the activation temp of this stuff, using hot-glue will always bother me unless I can prove to myself that the temp it goes at is at least triple what my glue gun is set.

[Bert]

Generally, the ignition temperature will be near the melting point of the oxidizer.

[Kingtaling]

Generally, the ignition temperature will be near the melting point of the oxidizer.

So maybe just stick some KClO4 into a pan and melt it?
Would there happen to be a place on the web that gives this info? It would be safer than trying it out on my own.

[Bert]

I think a bit of googling and a quick visit to Wikipedia would answer that question. Then check the mp of Potassium and Sodium chlorate and see if you can draw any conclusions about relative sensitivity?

One of the usefull bits of info to be found in Shimizu's "Fireworks: The Art, Science & Technique" as well.

[Kingtaling]

I think a bit of googling and a quick visit to Wikipedia would answer that question. Then check the mp of Potassium and Sodium chlorate and see if you can draw any conclusions about relative sensitivity?


It looks like KClO3 has a MP of about 700*F. I cant imagine KClO4 being far of, so the average temp of my hot-glue gun cant be more than 250*F (ill check with a... heat gun?) So I guess that quells my fears.

In other news, My KNO3 came today, and got ripped apart at the post office (by accident? or...) they tell me that when the "white powder" came out of the box everyone ran and the place was quarantined for over an hour.
The police and a post office employee showed up here asking "what is this" and "whats it for"
I stuck my finger in it and put it in my mouth and said "its a food salt perservative" this seemed to satisfy them.
I was worried I was going to die, though, I couldnt remember for the life of me whether it was KNO3 or KClO3 that was safe to eat.

[nbk2000]

So naturally, the first thing you do have having a 'white powder' incident that brings the cops to your door is come here?

That's a real bright move. :rolleyes:

What do you want to bet all your internet traffic is being monitored for the near future?

Even if it was chlorate, a fraction of a gram isn't going to hurt you.

[deadman]

Well luckily it was Potassium Nitrate you had not the Chlorate. That amount of either wouldn't be life threatening.

KNO3 could decompose to KNO2 in which case nitrite poisoning could be a possibility. That small of an amount wouldn't hurt you too much. After they left I'd have puked.

If it would have been KClO3 it would have been a very uncomfortable experience. The following is copied from the MSDS provided by www.jtbaker.com:

Causes irritation to the gastrointestinal tract. Symptoms may include nausea, vomiting and diarrhea. May cause abdominal pain, hemolysis, methemoglobinemia, cyanosis, anuria, coma, and convulsions. May cause liver and kidney damage. Death may occur from renal failure, generally in 4 days. Estimated lethal dose from 15 to 30 grams.

[Kingtaling]

Don't quote whole posts! :mad:

I thought about that, I'm paranoid like it... which is why I was having the stuff delivered to my shop, not my home, under a different name with a friends paypal account.

As far as they know, I was just an employee working at a shop that uses the "white powder" in its daily business.

My computer is at a remote location not linked to my perfectly legal yet somewhat paranoid activities. Nothing I've ever made, ordered, or used, is here.