633 replies to this topic

[Yugen-biki]

This is more of a question than a listing of formulas. But I have found some formulas that I?d like to try and maby get some feed back from you people here on the forum.

I am looking for comets with a head with colour. By comet I mean a star with a bright silver or gold tail. (The name comet fits many star formulas).
I have found that the number of comet formulas that has a colour head are very few. I have found some interesting formulas on page 76 in AFN 2. This is ordinary stars made of perc, parlon, a carbonate and a binder. But by adding 15 parts of 20-50 mesh Mg they magically stransforms into comets. Is this the way to go? Is Mg the optimum tail metall? Will Al make a longer tail or not work at all?

I have found a lot more gold and silver comets, and this is the silver one I have found (AFN 2; p.71) :
KNO3 64
BaNO3 30
S 16
C 16
Sb2S3 16
Al 9
Dextrin 16

I can?t find any info on the mesh of the Al. What mesh would work, and give me long tails?

The basic question is how do I make comets with a long silver tail and a coloured head?

[paul]

50?m Alu will do the job... The effect with the glowing head and the silvertail will come automatically. It burns with colour and while it jets through the air "loses" the sparks of aluminium and charcoal for example...

[Yugen-biki]

Are you saying that I can replace the Mg for Al in the "perc, parlon, a carbonate and a binder" star and have a good result?

[Phoenix]

Yugen-biki - Another option you could try is to layer two different compositions in the pump before pressing, similar to making a colour or effect changing comet. If the comet was strong enough you could use it unpasteded, but I suspect it may be weak at the join. If this happens you could wrap it with paper and then arrange the leader to ignite the top face as well as the lift charge (if the comet was large enough for a leader to pass by it), or maybe the lift charge would ignite the top face if it was well primed.

This is rather more complicated than simply adding spark producing metal to the composition, but none of the colour should be washed out this way. Note that I haven't actually done this myself, just read about it.

Stuart & Lord_dranack - I was thinking that the alcohol (meths) could be dried if necessary by taking hydrated magnesium sulphate (epsom salts), heating it to dehydrate it, then dumping it in the alcohol and leaving it to rehydrate with any water present, then filtering it out. I read about this on rec.pyrotechnics.

[BurlHorse]

I think If it were me, I would go with Al in the granulated form, 10 to 150 mixed Mesh, this will give the tail a delayed as well as immediate effect from the AL, Also, I have found that using pine charcoal, 80 to 100 mesh gives a great Tail with an almost lampblack hangtime, which in this case would keep up with the delay of the larger of the aluminum particles.

You can easily join different comets with NC Laquer as the adhesive, I have made quite a few stacked comets, and if you paper them, they will burn one effect at a time, if you leave them unpapered, all sections will take fire from the lift, So this is another way to achieve your goal of Color head and Long Hang time tail.

*TIP* For your Comets to Bond Well, Make sure that the comets you make in the first place are VERY well Compacted/Pressed Etc. and Then they must be dry as a bone before you try to bond them. Once those 2 requirements are met, you liberally smear both ends of the comets to be joined with NC Laquer, only time and experience will tell you how much to use, but for the first couple of trys, more is better, you can fine tune them later. Anyway, after the NC Laquer has had a couple of minutes to "Skin" over, Place your Comets Together as evenly round as you can and clamp them, I use the Small Hand grip Bar Clamps and have had good results. You only want enough pressure to really stick them but not crack them or render them to dust. So Easy on that trigger finger Hoss (with the Clamps

Another type thats cool to try are Matrix Comets, where you can load your comet pump with a bit of comp, then throw in a few different stars, adding Your comet Comp tofill it all in, then press them, Very Unique effects can be had with this, I won a Crackerjacks Comet contest award, like second place out of five for just such a comet, I called it the Silver Vampire Comet For Mental Effect...It was a pretty Basic Silver Comet Comp, With 3/8ths inch Ruby Red Stars, The effect was better than anticipated, with silver head and tail, But it litterally looked as though Blood was dripping from the tail of this comet, They were 1.5" OD Comets and were made 2" long.

Just some food for thought for you, Good Luck in your quest!

Regards,

Stay Green,

Bear

[Yugen-biki]

Thanks for the input!

I?ll try some comet experiments this year. I?ll have the results late this year.

[Phoenix]

Organic Yellow

A little while ago I enquired about yellow star formulas using sodium nitrate. Since I couldn't find any that were the sort I was looking for, I did a bit of experimentation myself and here is what I came up with:

Sodium Nitrate........70
Charcoal.................15
Sulphur...................10
Shellac.....................5

This formula is not as fast-burning as it may first appear. Sodium nitrate mixtures seem to burn much more slowly than the equivalent potassium nitrate mixtures. I haven't measured the burning rate of this, but I've just been shooting a few stars, and it seemed to be "about right."

I have not noticed any hygroscopicity problems with the sodium nitrate, but the weather has been very warm and mostly dry recently.

The composition was prepared by ball milling the sodium nitrate, charcoal and sulphur together dampened slightly (as for BP). The composition dried easily, despite the sodium nitrate's hygroscopicity. The dry mixture was milled for a couple of minutes to break up the grains that had formed as it dried and reduce it to a fine powder. The shellac was then diapered in. (BTW, is it considered acceptable to ball mill a mixture like this with shellac? It would be simpler just to stick the shellac in with the powder for the final two minute milling session, if that was OK).

The comp was then rolled over 5mm Tiger Tail stars, using methylated spirit as the solvent, until they were about 7mm in diameter. When dry (~24 hours) they were rolled up to about 10mm with the remaining comp. Since the 7mm stars were found to be quite difficult to light, and liable to blow blind, the stars were finally primed with straight BP on the surface (no binder was added to the BP, but since it was only a thin layer it stuck to the wet stars OK).

The stars are quite bright - comparable to the organic chlorate colour stars I have tried. The colour is quite a pleasing warm gold. Before I actually started to try out sodium nitrate comps, I was half expecting an unpleasant, street-lighty sort of effect, but I am very satisfied with the colour from this formula. I don't think that these stars produce much of a tail, although since I rolled them over a streamer comp it is a little hard to judge. The sodium nitrate comps were rather drossier than potassium nitrate comps, but this did not seem to be too much of a problem. I had one or two sparks come down, but they were probably from the streamer cores, and would not be such a problem in a shell.

[Jerronimo]

Hey guys I need some help,

In november last year I made a silver star formula, it worked really great.
Nice clean silver.

this is the formula:

kno3 : 60
Al spherical 200 mesh : 20
Sulfer : 14
Charcoal : 6
boric acid : 1
dextrin : 5

A couple of weeks ago I made the same formula again,After rolling some stars with the comp, I filled some shells and shot them.
It behaved differently, instead of a nice silver streak I got more of a silver twinkling effect.
This was still a nice effect, but not the one I'm after.
Maybe I made a mistake last year when I was writing down the formula, I don't know.

Edited by Jerronimo, 22 June 2004 - 07:19 PM.

[alany]

Was the charcoal different? Perhaps high in ash? That might explain glittering.

[paul]

I think it was the different particle size of the chemicals. You can?t manage to get your chemicals the same particlesize every time.

The mixing procedure may be another source of error.

[Phoenix]

The glitter effect is supposed to be sensitive to how much the composition is wetted, so perhaps your formula is too. Seems less likely that the other two suggestions though.

Edited by Phoenix, 23 June 2004 - 02:07 PM.

[Jerronimo]

Thanks for the suggestions guys,

The chemicals are exactly the same, exept the sulfer.
I made some of the same comp. yesterday and tried a small non wetted batch.
It seems to burn less ''fluidly'' then the comp I made in november.

I can shoot some movies of the comps burning, if somebody is willing to host them
you guys can have a look.

Maybe somebody has a succesfull formula with these ingredients?

[adamw]

Yes, remember that a glitter comp is supposed to be very 'drossy'. It is essential to the reaction.

[alany]

Here's an orange go-getter composition for the AP-challenged. I've been experimenting with it for a few days, seems to work quite well. A 5 mm ID go-getter about 15 mm long with a thin piece of blackmatch down the middle flys all over the place for several seconds:

7 Potassium Perchlorate
1 Aluminium (-325 mesh, spherical)
1 Sodium Benzoate
1 Parlon

Dampen with acetone and press into a small tube, push a piece of blackmatch down the middle and leave to dry out completely (use a sparkler wire to make the core first if you do it fairly dry). You don't need to make it into custard, but doing so works just fine, it will shrink more and burn somewhat slower.

Add 1 part Copper Oxide (black) for a whiteish purple, not dominated by the sodium line as you might expect. It leaves a short flitter tail of goldern sparks. Strangely with the Copper Oxide it burns about the same speed, probably some kind of catalytic effect. Some magnesium oxide brightens it quite a bit.

I haven't tried Cryolite yet, might be more yellow. In theory you could use Potassium Benzoate if you have it and add Barium or Strontium Carbonates for other colours, but again I haven't tried it yet.

Being roughly half whistle, half falls composition it should be treated with due respect.

You could try swapping the Benzoate for Salicyclate. It may be too hot for moist hand-pressed grains, but adjustments could make it an even better go-getter propellant.

--

Edit, purple organic star comps for Creepin':

Shimizu KP #2

64 Potassium Perchlorate
9.5 Red Gum
8.7 Parlon
7.8 Strontium Carbonate
5.2 Copper Oxide (black)
4.8 Dextrin

A very nice balanced purple, fairly fast burning.

Bleser KP

68 Potassium Perchlorate
11 PVC
9 Strontium Carbonate
6 Copper Oxide (black)
5 Dextrin

Good purple, slower but a really nice colour IMO.

Edited by alany, 29 June 2004 - 12:37 PM.

[Creepin_pyro]

Looks good - I shall be trying the Blesser purple, and the orange go-getter (I've been waiting for a decent excuse to get my acetone out :-) )

Here is a formula I've decided to use in my first shperical shell.

The formula is the alternative to a Magnesium fuelled one bound with Polyvinyl Acetate (hence the 65:35 Mg/Al)

Brilliant Red/Titanium star from AFN iv

Strontium Nitrate ............................................40
Titanium 20-40 mesh .......................................20
Magnalium 65:35 Atomised 150 mesh .............. 15
Polyvinyl Chloride ...........................................15
Accroides Resin (Red gum) ...............................5
Potassium Perchlorate ......................................5

I used Fe/Ti <70mesh to replace the Titanium and 90:10 granular Mg/Al instead of the 65/35.

I was quite surprised to see the amount of metal in this comp! Ground tests look promising - nice deep red throwing lots of sparks, and LOUD - that's probably my weird 90:10 Mg/Al. Shouldn't be too long before I get some in the sky :-)

I used a simple BP prime with Silicon powder added to see how it fares compared to Velines hot prime. Wish me luck!

Edit: I did a stargun test with one.

Brilliant red Titanium star test

The question is - do we think these stars would be suited to a 3" or a 2" shell? Any thoughts?

Edited by Creepin_pyro, 29 June 2004 - 11:08 PM.