primes

[pyrochris732]

Guys,

 

I made the ruby reds last night but only coated them in meal powder. I would like to make a nice "HOT" prime to to ensure they light. I read some of the recipes and I know where to go for them (pyrocreations), however, I am a little confused when it comes to adding them:

 

This is the one I want to try:

 

Potassium perchlorate.............................80

Charcoal, fine....................................15

Red gum...........................................4

Manganese dioxide (optional) .....................9

Aluminum, (fine flake or pyro grade; optional)....4

Dextrin...........................................2

 

or this one?:

 

Prime (bleser)

KClO4.............75

Red gum...........12

Charcoal..........9

Dextrine............4

 

Do I make a paste out of it so it gets almost painted on the outside of the star? Is it like the thick clay-like consistency of regular stars that gets wrapped around a dry star?

Thanks,

 

Chris

Edited May 13, 2010 by pyrochris732

[jwitt]

Allow me to dump a bit of stuff from my notebook. Ruby Red is very similar to Veline, just using Sr nitrate instead of carbonate, if I recall. (One problem with nitrate is that it's hygroscopic, something to think about)

 

I will be using "fencepost" at the bottom of this message for my color stars, but this is most of the information on primes I kept. There are links in these snippets too, more good reading. The reason I'm including all these notes is that all this different info really gets you thinking about all the options, and then you pick one to suit.

 

(Once again, this is good info from experienced guys, but I'm just a newb doing the basic research and newb projects.)

 

 

For lighting coloured stars with a much higher metal content than Veline, (therefore much harder to light), I do a two step method. To light the coloured composition I use

 

 

60% Potassium perchlorate

10% Charcoal

10% Red Gum

10% MgAl

5% Red Iron oxide

5% Gum Arabic

 

Then, to light that,

 

75% Mill dust (BP)

10% Potassium perchlorate

10% Magnalium

5% Gum Arabic

 

Fairly thin layers of each are all that is required to light some very very stubborn stars at high speed. This is overkill, but with primes, that may be good.

 

Pasted from <http://www.amateurpy...20stars__st__20>

 

 

 

Veline or fencepost: "As far as binder, I mix it without one and spray 4% gum arabic. Others have added dextrin or have even put it down with some NC lacquer and all have gotten good results. Basically stick it to your stars with anything you want so long as what you're using burns (hehe). " red gum / alcohol

 

Pasted from <http://www.amateurpy...501entry61501>

 

66.67 - Potassium Perchlorate

13.33 - Charcoal Airfloat

8.89 - Red Gum

5.56 - American dark. -325 mesh

5.56 - Dextrin

 

The author uses a 75-15-10 mix of KClO4, AF Charcoal, Red Gum with an addition of 1oz/lb fine metal (MgAl, American Dark Aluminum, or silicon) and 1oz/lb dextrin. The above percentages are what the formula works out to. However, I hardly think it's necessary to measure out to the 100th or even 10th of a gram to achieve proper results.

 

Pasted from <http://www.apcforum....=veline+alcohol>

 

55 KClO4

20 airfloat, I use Skylighter

10 -325 Magal

5 dextrin

5 redgum

5 -325 bright flake Al

 

Pasted from <http://www.apcforum....=veline+alcohol>

 

When cutting stars I roll out the composition to desired thickness then lightly sprinkle prime over the top surface using a sieve. I roll this prime into the star "patty" to get good surface contact, the patty is then flipped over with a thin spatula and priming is repeated. The stars are then cut and dried as normal. Once dried I spritz them with gum arabic solution and add the prime of my choice to completely cover the star, this gives a fluffy outer prime that takes fire easily.

 

In canisters you may not need to secondary prime the whole star, just a light dusting on the originally primed surfaces so they take fire easer. I believe this as only one face of the star is intimate with the burst, therefore whole priming may not be necessary?

 

BTW I use a lightly milled greenmix with 5%Si and 5% MgAl as my prime.

 

Pasted from <http://www.apcforum....=veline+alcohol>

 

Name: Fence-post prime

Type: Prime

Source: Eugene Yurek

 

Potassium Nitrate 65

Charcoal Airfloat 12

Sulfur 10

Diatomaceous Earth 5

Silicon, 325 mesh 5

Charcoal, spruce, ball milled 3

 

Pasted from <http://www.amateurpy...__1entry36478>

Edited May 13, 2010 by jwitt

[pyrochris732]

thanks for the reply. So I have decided to go with the following since these are the ingrediants that I have:

 

66.67 - Potassium Perchlorate

13.33 - Charcoal Airfloat

8.89 - Red Gum

5.56 - American dark. -325 mesh **(the al i have is indian blackhead- probably at least 600 mesh)**

5.56 - Dextrin

 

My emerald greens are drying right now, they were just pumped. So for the above should i make a viscous paste and mold it around these stars or do you think i should make a very watery - almost solution- type of mix and paint it on?? This is the step that I cant find good info on at all surprisingly.

 

Regards,

 

Chris

[al93535]

Why not just use a standard black powder type based prime with a small amount of metal added? These primes take fire MUCH easier then a perchlorate based prime will. And why waste the much more expensive perchlorate on a prime?

 

Here is my personal favorite prime:

 

Potassium Nitrate 62%

Airfloat charcoal 18% (any kind)

Sulfur 10%

-325 mesh MgAl 5% (you can use any fine aluminum or Magnalium here)

Dextrin 5%

 

This is screened twice though a 50 or 60 mesh screen.

 

Spray the stars with water while rolling in a bowl and sprinkle prime on them, repeat until you have a 1 to 2 mm thick layer.

 

This prime ignites ALL my stars except really high % metal stars like 45% +, and then I would use a solvent based prime on those.

[pyrochris732]

Excellent, Al. I will do just that then. I saw all kinds of recipes and info on primes but nothing really saying how they get applied to the stars. Thanks,Chris

[jwitt]

Al- since he's using Strontium Nitrate, should he spray the dry stars with water to prime?

 

Note that I'm not trying to contradict you- I'm really ignorant of this stuff, but it goes a bit contrary to my research, which is why I'm asking. (And I'm gonna be making these stars very shortly)

 

But also- I heard that the sure-fire (haha) way to get perchlorate stars to light is to use a hot prime, followed by a BP prime, perhaps spiced up with a dash of metal.

 

Another thing I'm curious about, since we're on the subject- blackhead Al vs. 325# Al. Primes that burn real hot, but fast, aren't supposed to be as effective as primes that burn a bit slower...so would it be a disadvantage to use blackhead Al? (Aside from it being fairly pricey)

 

It's certainly not a star you'd want to risk blowing blind, after gathering up all the goodies to make it ($$). That's why I'm pressing the issue.

 

Of course another disadvantage to step priming would be building up the star's size and being able to cram fewer of 'em in a shell.

Edited May 14, 2010 by jwitt

[pyrochris732]

guys this info is super helpful..i really appreciate it.

 

Im excited to get my willow charcoal, its in the mail and it should come next week sometime.

[jwitt]

At least that's an area that I am qualified to speak on- officially- it is AWESOME to have good charcoal on hand, especially when you figure how much BP you can make from the amount of charcoal you have...even buying and shipping it is pretty cheap all things considered.

 

FWIW- from my understanding (only based on research...for now...) stars get harder to light as you make harder breaks. Good BP coated hulls and a tiny little whistle booster (or no booster at all) is supposed to be much less likely to blow stars blind than a really hard break.

 

I can say from limited experience that a 3" shell pasted with 5 turns of 3-strip method (3/4" gummed tape) and a bit over a gram of whistle mix sprinkled in (coffee milled KClO4, fine Na Benz, +Fe2O3) will give a very nice break with even the mediocre rice hulls I used in that shell. It really impressed me- I figured it would kind of dump or look crappy, but WOW. People recommend a booster charge for 3" shells to even out the break, or make it harder for certain things like spider web, but you really don't need much to make an impressive display.

 

Bottom line- if you're worried about blowing stars blind, don't think you absolutely need to break the shell real hard. With your good charcoal and proper BP manufacture, things ought to work really well. When you confine that stuff...oh man!! It was amazing for me to experience, having only done some BP shooting with goex and burned a few piles of homemade stuff. You'll also gain an immense respect for the materials you're working with after you see how they perform.

Edited May 14, 2010 by jwitt

[dagabu]

Interestingly though, in plastic shells, you want to use a flash bag in the center of the shell to get the uniform break that you get in paper shells with BP break.

 

I really like "dump" canister shells, not poka shells mind you but rather a soft break that allows a good spread but not necessarily spherical. I have several shells that I will launch tomorrow night and some rockets as well (think competition) where I will be using timed reports, falling leaves and inserts.

 

I like color stars but I get to see tens of thousands of them from China every year but only a handful of truly interesting shells. Streamers, willows, electrics and firefly are my favorite and horsetail are just amazing.

[pyrochris732]

interesting... yea i cant wait to test out a shell for the first time. Im sure it will be gratifying to fire them and if they come out good, ill know that it was all done by hand, from scratch. This hobby is so much fun, but I have to be careful because I live in a place where fireworks are illegal (not CA).

 

If anyone else reads this, and since jwitt mentioned black powder production, what screen would you recommend me getting for lift BP? 12 mesh? It will be powerful BP since it will be willow coal and ball milled.

 

regards,

 

Chris

 

 

[jwitt]

Well, I'll bite again.

 

4-12 mesh is 2FA.

12-20 mesh is 4FA.

 

I granulated mine through a 10 mesh screen and allowed it to dry. After drying, I had some big lumpy stuff, misc grain sizes, and some dust. I dumped it all in my nesting screens (12, 20, and 30 mesh) and screened it. The big chunks retained on the 10 mesh were gently broken up until the pieces resembled the average stuff retained on the 10 mesh, and everything was swirled around a bit more.

 

This yielded me some +10 mesh, a big pile of -10+20, some -20+30, and some -30 through dust.

 

Since my main goal at the moment is preparing lift powder and 4FA is acceptable lift for small shells, I chose to re-process my fines. This could also be retained and thrown in the BP prime stash- since it's a mix of sizes, it ought to be good for creating a rough surface that takes fire easily. (I've researched and learned that slower powder, like green mix, is good prime, so I figure some more energetic BP in there as well would do very nicely since it takes fire like crazy)

 

Note that this may not be ideal, as I've read 2FA is the best size for lift, but it's what I'm doing. At least until I get around to getting a screen bigger than 10 mesh so I can have proper sized 2FA.

Edited May 14, 2010 by jwitt

[al93535]

Sure you can use water to wet the stars to prime them. The only time you really run into problems is if you get crappy strontium nitrate. Ask your supplier where they obtain thier supply. The best comes from barium and chemicals, it's super high purity.

 

Just the standard service chemical nitrate will dry just fine, unless its always raining, 40 degrees and you are drying them in the garage! Just let them dry with slow air movement in the shade in shallow trays!

 

If you feel you have impure nitrate, or just dont want to wait for them to dry. Use a sprayer and mix 10 mls of 10% NC lacquer with 40 mls of acetone. Spray the stars and sprinkle the above mentioned prime on them while rolling in a bowl.

 

 

I break my shells with either a scratch mix of BP coated rice hulls 6:1, or KP coated rice hulls 6:1. Then I add 2 grams of flash ( perchlorate, 10890 flake al (american dark) and sulfur) for a 4" ball shell. 4 grams for a 6 inch. IMHO, pick a break like BP or KP, and a ratio, then adjust the break with a flash booster. My shells do not break super hard, but are perfect for me!