Potassium Perchlorate Stars and Acetone - Help?

[Skycastlefish]

Hey guys,

I broadening my pyro horizons from BP based streamers to a purple star that hasn't any BP components at all. In particular Yankie Purple...

 

KClO4.........................50

Parlon.........................15

CuO............................12

SrCO3...........................9

Red Gum.......................8

MgAl (325 mesh)............5

My interest is in safety. When I think of potassium perchlorate and metal, well, I think of reports. In what ways should a KP based star comp be treated differently than a BP based comp? I know I shouldn't ram any KP comps, but how friction sensitive is a KP base like Yankie's purple? Also, I keep finding compositions that instruct me to screen metals with the other components. I thought screening metals was a bad idea? Lastly, I have heard so many horror stories about acetone that I've decided I'm not dedicated enough to the hobby to use it. Regardless of how unlikely it may be, I just don't want to use it. Will the binders in Yankie's Purple work properly without a solvent? The original post says you can add dextrin and use water to bind. I presume that means I should use dextrin in addition to the other binders?

Thanks

Edited July 21, 2010 by Skycastlefish

[Peret]

That's the same list of basic ingredients in the Veline system, which makes a fine purple by mixing red and blue. I wouldn't grind them, but I don't believe the mixtures are particularly sensitive; I've rammed them to make pumped stars, though mostly I cut them. +5% dextrin or SGRS binds them rock hard. Of course they have water in them when you use these binders, so that may make them less sensitive. All the same, I know of no special precautions that need to be taken as long as the mix doesn't include sulfur ot other sensitizers.

 

It's hard to incorporate the MgAl thoroughly and evenly without screening, though it can be done. The reason people say not to screen metal is it gets caught in the mesh, but if you use -325 metal and mix through a 20 mesh screen that shouldn't happen.

 

The red gum and parlon aren't really binders, their function is fuel and chlorine donor - you can't leave them out. True you can use them as binders with alcohol and acetone respectively, but they aren't very good - the red gum is too sticky and parlon isn't sticky enough (my opinion anyway). I too am wary of using an acetone binder, since the explosive concentration in air is only in the order of 2-3% and being heavy, that concentration of vapor can easily accumulate around your ankles if the air is still.

[Mumbles]

I find them to have the opposite problems. The red gum isn't sticky enough, and the parlon is too sticky.

 

Anyway, just add 4 or 5 parts dextrin or SGRS and cut away. I screen all of my compositions, including some that would probably make you cringe. There is just no better way to incorporate chemicals together. I use a 40 or 60 mesh screen most of the time. My screens are stackable, so I stack something like 16 --> 36 --> 60 mesh on top of one another. By the time it gets through all of them, the chemicals are pretty well incorporated. A quick stir makes it fairly homogeneous. They get completely mixed by wetting for pumping or cutting. I'd give it another screening through the 40 mesh before using it to roll or prime or something like that.

[Skycastlefish]

Thanks Peret and mumbles! I was reading that MgAl can sometimes react with nitrates. Are they referring to the same reaction that can occur between nitrates and Al? If so, can boric acid help? The reason I ask is that I plan on priming these purples with meal powder. Is that regarded as a generally safe practice? Edited July 21, 2010 by Skycastlefish

[Twotails]

Im not too sure on the MgAl perspective of boric acid, but i've had a Mg composition corrode(with heat, luckly i had it outside in winter, so even if it had get hot enough to self ignight, it was on a table in the snow) when i used a red gum bound composition with acetone(from what i have read Redgum can be slightly acidic, and the acetone wasnt dry(now i dry it!) so i think that ate the Mg. I would guess that that carbonate in the formula(above) would act as a buffer?

 

I've never tried that formula to say for sure, as i dont have the parlon, but i have made blues, purples, and greens useing similer comps(some not working to my like, or colors washed out) and to incorperate the metal, a few times i've made a thick slurry(with a non-aqueus solvent and binder) with about 1/2 the mix(just wetter than normal to make like a paste) add the metal, and incorperate the rest of the mixture(stirring greatly) that way i didnt have to worry about screening metals, and the metal was(most often than not) suspended in the composition fairly well. screening is pretty good though(sometimes I wet the mixture into a ball and granulate it though a screen with large opinings, maby 10-16 mesh a few times, then make stars) i have noated that if too much solvent is used on Redgum stars, they get a little harder to cut, and dry somewhat harder(to cut down on acetone i use 50/50 Alcohol/Acetone, not too bad starting to like dextrin more, cheaper, and not as smelly(although red gum smells good to me, if there was a redgum body spray, i'd buy it!)

 

Can the above be made with saran or PVC(i'd guess saran?) and be rolled?

[Mumbles]

If you read the thread on the composition, you'll see I ran out of parlon part way through. I used a mix of parlon and saran, and it worked fine.

[Twotails]

Hmm, then i'll have to give it a shot. thanks

[jwitt]

Just cut some parlon stars with acetone the other day. I could swear I read that nitrile gloves are impervious to acetone. The gloves held up, but I swear it felt like I was dipping my hands into strong solvent (oh, reminds me of the happy old days of constant exposure to PPG's DTL-10 thinner). Changing gloves after kneading the dough ball helped.

 

Also-

 

• I used a round kitchen colander instead of my nice mixing screens to screen the 500g batches- maybe 60 mesh- plenty big to let the very fine metal through.
• I aimed a fan at the floor, on low, at a place near my feet from across the room to provide a gentle breeze to clear out some acetone fumes.

PS if you keep working with this sort of composition, try the Ruby Red with Strontium Nitrate. Dry the acetone and the strontium before making. The batch I made was like, well, tiny little road flares. Amazingly bright and (IMO) great saturation.

Edited July 22, 2010 by jwitt

[Skycastlefish]

So, yay or nay on the bp prime?

[TheEskimo]

BP+5-10% -325magal works fine for me.

[Skycastlefish]

I was reading that MgAl can sometimes react with nitrates. Are they referring to the same reaction that can occur between nitrates and Al? If so, can boric acid help?

Hey guys -- I just read that boric acid actively corrodes Mg and MgAl, especially in the presence of H2O.

[Mumbles]

I knew, rather was corrected, that it attacked Mg. Through experimentation I've found that it corrodes MgAl too. I ruined several batches of glitters by doing that. The flashes and tails really get killed. You can see one batch in the below video. That glitter is normally long with bright white flashes over a Charcoal tail. Very attractive. It doesn't look bad right now, but it's a mere shadow of what it can be.

 

[Skycastlefish]

Nice timing on that shell! It breaks just as you see the suspension give and feel it accelerate toward the ground. Like hanging an ornament. Have you noticed a similar effect while using boric acid with Al? Like an Al glitter or something? I have to admit, I'm not experienced enough to see the flaws in that glitter.

[Mumbles]

I'll try to get a video of a good batch to compare against. Like I said, it's not too bad, but it can be much better. With aluminum, I haven't noticed the same thing unless the stars are allowed to stay wet way too long. I cut all my glitters, but still try to dry them pretty fast. Boric acid is definitely quite corrosive to MgAl. It harms the effect, but doesn't cause any noticable reactions or heating or anything. The boric acid seems to help prevent anything happening with aluminum. I really only use boric acid soln now if I am cutting Al glitters with NaHCO3 or Na Oxalate.

 

I was pretty excited about the timing on that. It was a new batch of lift, and it works almost identically to the commercial lift I was using.