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Diagnosing "wimpy" 0.5g firecrackers. 70/30 flash


JohnWI

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I decided to start my studies with what I thought would be the most basic of salutes. As I mentioned, I'm a chemist by training, and have a GREAT DEAL of respect for all things "energetic".  I rolled some cardstock 3/4" cases, and prepared flash (mixing via rollilng on wax paper) in small quantities (a couple grams at a time).  All the precautions--PPE, outdoors, away from structures. Leather gloves.  I have no intentions of ending up in jail, hospitals, or morgues.

In any case,  I wanted to make something with a respectable "pop", but nothing that would boom, or fall into really destructive device territory.

I fired a few of them today.   I'm using german dark aluminum and K-perchlorate, both purchased from a recommended pyro supplier.

I didn't have proper end plugs, so I used 3/4 cardstock disks (3/4 is almost exactly the diameter of disks used in 12ga shotgun shell shot covers).  I glued them in place, and used several layers of craft paper, modpodge, and white glue to secure them.  When you press on the dried disks, their is no flex at all.  I think they are really strongly adhered.

They do "pop", but I was really unimpressed.  At 0.5 gram, I was expecting a sharper "crack".  This just sounded smaller and deader than I was expecting, with a surprising amount of white smoke.  I could not find fragments of the cases to examine further.

I'm suspecting that, since we have been getting around 4" of rain a week for 2 months, things are just damp.  My perchlorate arrived finally powdered, but already in a few weeks is developing clumps. They are easy to break up, but this must be evidence of excess water?  The paper cases, also stored in the basement, were actually kind of "squishy" too.  A couple hours in the sun and they are rock hard.

Anyway, if you shake the salutes, it almost sounds like their are larger pieces in it.  It's not what I would have expected, considering the materials going in were finely divided (I carefully pulverized the perchlorate alone, then mixed the powder).

How should one diagnose firecrackers with an underwhelming report?

I did order some paper end plugs from the same place I got the fuse (another respected supplier), but they seem to almost be made of like 2 layers of craft paper. They are very flimsy.  I seriously doubt they can contain a whole lot of pressure.

I'd like to repeat, I'm going small.  Something respectable, but not nuts.  Sub-cherry bomb territory stuff.

Thanks for any info.    I put the perchlorate and aluminum in a gallon ziploc bag with a container of Damp Rid (calcium chloride dessicant), to hopefully rule out damp/clumping powder.

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That's strange 70/30 didn't produce the results you were hoping for. I use an almost identical method and my .8 gram "finger bangers" slap you in the face with their shockwave and set off every car alarm on the block. I use Indian blackhead plus a tiny pinch of sulfur. I roll the tubes on a 5/16 dowel and cut them about the size of a Tootsie roll. Only real difference I can see is I use thicker end plugs.

Maybe try an extra layer or two of paper. Or a different size tube.  One thing I know is there's a "best size" for any quantity of powder.  Just trial and hopefully not error

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Are your ingredients really fine enough and are you sure your way of mixing really was effective?

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The perc certainly needs to be 200 mesh or finer, and both ingredients need to be dry. SEPARATELY the ingredients can be dessicated or heated to 200F for a day to a week to drive off moisture.

Sometimes the crack is improved by a stronger casing.

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A gram er so of good Vitamin F in an open Dixie cup will rattle close windows. Something’s up with moisture would be my guess.

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On 6/30/2024 at 8:38 PM, JohnWI said:

I decided to start my studies with what I thought would be the most basic of salutes. As I mentioned, I'm a chemist by training, and have a GREAT DEAL of respect for all things "energetic".  I rolled some cardstock 3/4" cases, and prepared flash (mixing via rollilng on wax paper) in small quantities (a couple grams at a time).  All the precautions--PPE, outdoors, away from structures. Leather gloves.  I have no intentions of ending up in jail, hospitals, or morgues.

In any case,  I wanted to make something with a respectable "pop", but nothing that would boom, or fall into really destructive device territory.

I fired a few of them today.   I'm using german dark aluminum and K-perchlorate, both purchased from a recommended pyro supplier.

I didn't have proper end plugs, so I used 3/4 cardstock disks (3/4 is almost exactly the diameter of disks used in 12ga shotgun shell shot covers).  I glued them in place, and used several layers of craft paper, modpodge, and white glue to secure them.  When you press on the dried disks, their is no flex at all.  I think they are really strongly adhered.

They do "pop", but I was really unimpressed.  At 0.5 gram, I was expecting a sharper "crack".  This just sounded smaller and deader than I was expecting, with a surprising amount of white smoke.  I could not find fragments of the cases to examine further.

I'm suspecting that, since we have been getting around 4" of rain a week for 2 months, things are just damp.  My perchlorate arrived finally powdered, but already in a few weeks is developing clumps. They are easy to break up, but this must be evidence of excess water?  The paper cases, also stored in the basement, were actually kind of "squishy" too.  A couple hours in the sun and they are rock hard.

Anyway, if you shake the salutes, it almost sounds like their are larger pieces in it.  It's not what I would have expected, considering the materials going in were finely divided (I carefully pulverized the perchlorate alone, then mixed the powder).

How should one diagnose firecrackers with an underwhelming report?

I did order some paper end plugs from the same place I got the fuse (another respected supplier), but they seem to almost be made of like 2 layers of craft paper. They are very flimsy.  I seriously doubt they can contain a whole lot of pressure.

I'd like to repeat, I'm going small.  Something respectable, but not nuts.  Sub-cherry bomb territory stuff.

Thanks for any info.    I put the perchlorate and aluminum in a gallon ziploc bag with a container of Damp Rid (calcium chloride dessicant), to hopefully rule out damp/clumping powder.

Well i see in the making some critical point. First, the perchlorate must be sifted few time before add Al and S that must be sifted on the KP, before of that a fluffing media must be added some like Rice hulls or bran, not more than the 10% of the comp, this would solve your problem, i tested Comp in 1 layer of paper and 250 milligrams works fine for play banger

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Potassium perchlorate is not particularly hygroscopic, so the issue probably isn't moisture. My guess is that your chemicals weren't mixed intimately enough, as this will certainly affect the report in small quantities. What I do, is run the perchlorate through a 100 mesh screen alone, and then again after incorporating a SMALL amount of the aluminum - the amount is small enough that the resulting mix does not yet have any explosive potential, as it is drastically under-fueled. This produces a light grey free-flowing powder and prevents the perchlorate from forming "soft lumps" within the mixture. The rest of aluminum is then diapered or gently shaken to mix, whatever method is most comfortable to you. This process allows you to incorporate the two components throughly without additional risk, and is often used as an aid to binary mixing. Also, in very small reports (>0.5g), it is important to ensure that the hole in the case where the fuse enters is not excessively large or weakly reinforced - I recommend using the thin 1.8 mm visco or good quality paper fuse so that the fuse hole can be made smaller = more complete confinement. 

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I would suggest following the suggestions to finely screen your perc, as well as making sure your sufficiently mixing the vitamin F in the sealed container/tube . Diaper method works but isn’t fast, and not best for intimate mixture. 
a small burn test in a tissue will tell if mixed proper. A strong thump is a successful mix , a hiss or strong burn isn’t mixed well. 

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Are you 100% sure there hasn't been a mix-up and you do have very fine aluminium powder but it is spherical instead of flake.

What you describe performance-wise reminds me of the first time I made flash with good perchlorate but 300 mesh atomised spherical aluminium.  Burned terribly compared to how it was supposed to.

The spherical aluminium has much more surface area compared to flake and the rounded edges don't take ignition as efficiently as the rough thin edges of flake.

Otherwise, all I can think of right now are what was mentioned above, moisture in the reagents or not enough mixing.

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