Flash mixing

[kpknd]

How do you mix your 70/30? Mine likes to slide over the surface of the paper, maybe it is bacause I am using news print. I usualy just carfully pour it back and forth a few times.

 

Edited October 14, 2013 by kpknd

[nater]

Binary method.

[kpknd]

Binary method.

I have to plead ignorance on that one. ????

[AdmiralDonSnider]

I usually diaper it, placing the finely powdered chemicals in the middle of a sheet of kraft and mixing it by alternately lifting the edges quite a few times until a product of a single color results.

[Shadowcat1969]

If I need mixed flash and the binary method won't work, I actually started a hybrid technique based on a post I saw a few weeks ago (method attributed in that post to Ned Gorski, I don't know if that's true or not)

 

I take about 10-20% of the aluminum (so if you are using 30gr of Aluminum for a 100gr batch use about 5gr of the aluminum) and all of the Perc and shake it (don't push or rub) gently through a 20 mesh screen to get the mixing process started. This really helps keep the Perc from clumping up by getting the Al started mixing in. Then put the rest of the Al and the pre-mix onto some newsprint or kraft and diaper it.

 

for kpknd: You can use the binary method if you have a known amount you wish to make in a device (such as a report). You know how much you want to make, so you take the two components, put them in the device without pre-mixing, seal the device and rely on the movement/shaking of the remaing construction to mix the Al and Perc together inside.

[Jonathan]

FWIW, although against the grain, I consider 70:30 explosive, not flash. I know I'm in the minority.

 

There are some great Poof! Bright Fireball mixes that don't involve metals and that aren't friction or impact sensitive.

 

I'm not opposed to 70:30 and know it has its uses in pyro. I'm mainly concerned about language ("flash") circumscribing the limits of thought or discussion.

[SideGlance]

i use a small round tub and hand mix by slowly rotating

[nater]

Well Jonathan flash is the proper term and descriptive of the visual effect. Something that creates an illumination without metals does not fit the definition of flash as it pertains to pyro. I urge you to use the common terms so others know what you are talking about.

[PyroMick]

kpknd,

 

If you find the chemicals sliding on the paper as you diaper it, try crumpling up the paper first. The resulting texture in the paper help to "grip" the comp, and prevent it from just shifting around.

Edited October 15, 2013 by PyroMick

[MondoMage]

I have to plead ignorance on that one. ????

 

Essentially, you weigh out the individual components separately and also load them into the shell/insert/whatever separately. No diapering beforehand, no pre-mixing. Close the shell up and seal it up as usual (pasting or taping or whatever method you use). The handling of the shell will mix the components. I use this method for my salutes. Of course, I only make 1 3/4" ball shells for my salutes, which is plenty loud for me (and especially the wife, who must be kept happy so that I may continue to play). 10 grams of comp total makes the numbers simple (7g and 3g, respectively), plus a dollop of titanium if I feel like it. I paste them with several layers of pasted paper, although gum tape would work just as well. They seem to work just fine... then again, I've never done a side-by-side comparison between a pre-mixed and a binary salute, so take that with a grain of salt. I know people who use this method when pasting larger ball shell salutes on the WASP system, and they don't have any problems.

[TheExplosionist]

So basically the "binary method" means putting the ingredients inside a cardboard tube and shaking it vigorously? Wouldn't it be safer using a machine to shake it?

Edited October 15, 2013 by TheExplosionist

[countryboy7978]

You don't need a machine to mix flash in a binary method. Once it's sealed you have removed all sources of ignition as long as as you are talking about normal chlorate or perchlorate flash compositions.

 

I use the diaper method on a sheet of newspaper if it's a medium amount like 100-200 grams. In a paper bag if it's over that amount. The flash shouldn't slide around on the paper that much, it should tumble on itself. If it's only sliding around then you are not mixing enough at one time. Mix the amount of flash that you are going to use for the one project. If you are making 50 - 3 gram reports then mix 150 grams. If you are making twenty 100 gram salute shells mix then mix 2 Kg and be done. Expose yourself to the mixing process as little as possible.

[Nessalco]

If I need mixed flash and the binary method won't work, I actually started a hybrid technique based on a post I saw a few weeks ago (method attributed in that post to Ned Gorski, I don't know if that's true or not)

 

I take about 10-20% of the aluminum (so if you are using 30gr of Aluminum for a 100gr batch use about 5gr of the aluminum) and all of the Perc and shake it (don't push or rub) gently through a 20 mesh screen to get the mixing process started. This really helps keep the Perc from clumping up by getting the Al started mixing in. Then put the rest of the Al and the pre-mix onto some newsprint or kraft and diaper it.

 

 

Ned developed a technique similar to that.

 

To 70 parts oxidizer, add 5 parts dark al. Screen as vigorously as you like - it will not take fire. You can put a blowtorch on it for half an hour and it will simply melt. The small fraction tends to keep the pre-mix from clumping, and makes diapering much easier. Add your remaining 25 dark al and proceed as usual.

 

Kevin

Edited October 15, 2013 by Nessalco

[Jonathan]

If you want to mix flash, as defined by Nater -- metal powder + oxidizer -- my recommendation is, develop a good feel for your chems.

 

Powdered magnesium always produces a flash. I use 100 mesh and gently mix it with an array of oxidizers.

 

Powdered aluminum is less reactive than powdered magnesium.

 

My experience: You don't blow off an appendage with metal powder and an oxidizer in small quantities. You can blow off an appendage various ways.

Edited October 15, 2013 by Jonathan

[Shadowcat1969]

So basically the "binary method" means putting the ingredients inside a cardboard tube and shaking it vigorously? Wouldn't it be safer using a machine to shake it?

Not shaking it vigorously.

 

As an example making a 3" spherical report you can put your chemicals into the hemis individually, seal it, then simply the process of rotating the shell as you paste it provides enough motion to integrate the ingredients.

 

Some of the dangers associated with mixing flash with other methods have to do with the fact that it is exposed the whole time you are mixing, as well as filling your effect. In the Binary method, that particular issue is avoided because the ingredients aren't mixed and reactive until they are already sealed away from, for instance, a spark from static discharge.

[kpknd]

Thanks for all the replies, that clears that up. I shulda' probably said "Report" rather than flash, the only thing that might be a problem is that I just rely on the pass fire hole in the top of the rocket to ignite the comp, I wonder about using the binary, if the passfire might not fill up with metal or oxidiser and fail to work.

 

Jonathan, what is there for a fireball mix?

[FlaMtnBkr]

If you want to mix flash, as defined by Nater -- metal powder + oxidizer -- my recommendation is, develop a good feel for your chems. Powdered magnesium always produces a flash. I use 100 mesh and gently mix it with an array of oxidizers. Powdered aluminum is less reactive than powdered magnesium. My experience: You don't blow off an appendage with metal powder and an oxidizer in small quantities. You can blow off an appendage various ways.

Plenty of people have lost an appendage and/ or died from metal powders and oxidizers. Thinking otherwise is just foolish.

[nater]

When I want to make a rocket with a simple report, I usually use an empty "5 hour energy" bottle. I fill it up about 3/4 full with 7-3-1 in layers with a pinch of Ti or rice hulls. These small bottles will screw right on to the end of a 3/4" motor tube, so I coat some glue on the inside of the pressed motor and screw the motor onto the bottle. Then I add a filet of glue around the outside and a band of tape for extra insurance. The only time I have had one of these fail, is when I forgot to give it a gentle shake before flying. I ended up with a bright flash and no report. I don't usually use a bulkhead, so I have the entire flame from the motor to light the header. Another tip I received from SLD, is no matter what type of motor you are making, finish it with a very thin layer of hybrid fuel pressed last and no bulkhead. This gives a huge flame and will ignite whatever heading is on your motor.

[cogbarry]

I wouldn't be comfortable shaking vigirously. I also took Ned's tip and screen 5% aluminum to the oxidizer to reduce clumping. I still binary mix the remaining aluminum with the pre-mix if possible such as it is when making a ball shell. I let my WASP do the mixing. I also pre-fuse the passfire with black match before pasting so I don't have to penetrate into the mixed flash when removing magnet, inserting time fuse, etc.

[kpknd]

Can there be a danger of ignition by friction when placing an end cap, cork or other closure in the end of the tube with the comp residue between the plug and tube?

 

I see a reference to 7-3-1, is that 70-30 with 10% titanium?

[nater]

 

I see a reference to 7-3-1, is that 70-30 with 10% titanium?

The 1 is sulfur. It changes the tone a little and increases the sensitivity.

 

Generally, I prefer my salutes without Ti. I think it is an overused effect.

Edited October 22, 2013 by nater

[Jonathan]

Plenty of people have lost an appendage and/ or died from metal powders and oxidizers. Thinking otherwise is just foolish.

 

FlaMtnBkr,

 

You are correct, of course.

 

My message is, mix in small batches. And mix carefully. I think we're on the same page.

Edited October 22, 2013 by Jonathan

[JayDee2]

....... I let my WASP do the mixing. I also pre-fuse the passfire with black match before pasting so I don't have to penetrate into the mixed flash when removing magnet, inserting time fuse, etc.

 

In relation to using the WASP, could you please explain in more detail your technique to install the blackmatch and keep it in place in the tube while pasting on the WASP . Is the blackmatch just a tight fit and pre-positioned so the ends end up flush with the time fuse that is installed after pasting? Recently got a WASP and am researching fusing techniques.

[kpknd]

 

FlaMtnBkr,

 

You are correct, of course.

 

My message is, mix in small batches. And mix carefully. I think we're on the same page.

 

I only mix 10 gm. at a time.

[ollie1016]

You don't need a machine to mix flash in a binary method. Once it's sealed you have removed all sources of ignition as long as as you are talking about normal chlorate or perchlorate flash compositions.

 

I use the diaper method on a sheet of newspaper if it's a medium amount like 100-200 grams. In a paper bag if it's over that amount. The flash shouldn't slide around on the paper that much, it should tumble on itself. If it's only sliding around then you are not mixing enough at one time. Mix the amount of flash that you are going to use for the one project. If you are making 50 - 3 gram reports then mix 150 grams. If you are making twenty 100 gram salute shells mix then mix 2 Kg and be done. Expose yourself to the mixing process as little as possible.

 

I disagree completely. Mixing 2kgs of flash at once!!! Are you mental!?