Jump to content


Photo
* * * * - 3 votes

Tutorial: Crossettes

tutorialguide crossette crossettes how to splitting comets splitting comet

  • Please log in to reply
51 replies to this topic

#1 mathiasxx94

mathiasxx94

    Playing with fire

  • Full Member
  • PipPip
  • 46 posts
  • Gender:Male
  • Location:Norway
  • Interests:Pyro, Chemistry, amateur experimentalism, physics

Posted 22 January 2013 - 08:30 AM

Tutorial: Crossettes


Well, it’s time for my first guide here on the forum. Actually I wrote this guide back in December 2012 on a Norwegian pyroforum, but since I couldn’t find any guides for crossettes here I will give it a try here as well. As you may have understood already English is not my native language, let’s hope what I’m writing is understandable enough.
For those of you who haven’t seen the effect of a crossette yet, this is what I’m talking about. Amazing, isn’t it? I have to say that it’s not my shell:

http://www.youtube.com/watch?v=dvxUVg0e8gQ

A crossette star is usually a large pumped star. It differs from normal stars in that it has a “X” shaped cavity in one end that penetrates rather deeply, which is filled with a powerful burst charge, usually but not exclusively flash powder. The end with the cavity is capped, usually with a thick card disc glued in place, and that end, along with the sides are pasted with a layer of paper to ensure that the crossette burns only from the other end, ensuring that the effect works as intended. An alternative method involves dipping the crossette, with end disk glued on into molten wax to fireproof it.

But let’s get going, we start with the most important.

Equipment and chemicals needed:

· Hot glue gun w/glue
· Carton
· Craft paper and glue, I get good results with gummed paper tape
· Compass
· Scissor
· Crossette pump
· Black match or Chinese paper fuse ( not necessary)
· Wooden mallet, don’t use metals you will eventually destroy your pump

· Granulated black powder
· Star composition
· Graphite powder (optional)
· Burst charge



Posted Image Posted Image
Image of equipment and crossette pump, the right image is from Skylighter.

Procedure:
Start by making your desired star composition, when making this guide I used 100g Tiger Tail with 7g atomized aluminium added. The Tiger tail composition is maybe the one that every pyro knows by heart, but I still choose to write it down.
Potassium nitrate………………………………….44g
Charcoal (airfloat, preferably pine)……….........44g
Sulfur…………………………………………………6g
Dextrin/SGRS………………………………………..6g

This formula originates from the famous Japanese pyrotechnist Takeo Shimizu, SGRS (Soluable Glutinous Rice Starch) were undoubtedly used in the original recipe since this is the most widely used binder in Japanese pyrotechnics.
Streamers are very good looking and widely used in crossettes. The crossettes are roughly treated when the break charge does its work and nothing is more sad than pulverized stars. You may therefore slightly increase the amount of binder.

Posted Image Posted Image
As you can see from the pictures above the crossette tool is filled with the star compostion, you can choose between filling increments by eye, just push the tool into the box with the composition. Or you can choose the more dedicated and time consuming method, pre weighting amount for each crossette to get a far more superior symmetry.
Put the end of the pump against a flat suface, and hit the rammer a few times with the wooden mallet.

Posted Image Posted Image
The following can be a bit difficult, namely to release the crossette from the pump. I would highly suggest to add a few percent of graphite powder to the composition to decrease the friction. About 2% is a good amount to start with.

Posted Image
When you are finished pumping all your crossettes they need to be dried, stars with high charcoal content is known to dry very slow. Do not try to dry them in the sun, this might sound logic , but they are prone to the driven in phenomenon. My crossettepump makes crossettes with a diameter of 18mm, this resulted in a total of 18 crossettes with 107 grams of compostion.

Posted Image Posted Image
When they are fully dried you have to make the break charge, this part deals with a lot of tweaking. The first time I made them I used 50/50 potassium perchlorate/400# Magnalium flash, they do need a very strong break charge especially for such small cavities that this size offer, but it obviously was a bit to strong as you can see here:
http://www.youtube.com/watch?v=CtlGF1pez_8
However if the break charge is to weak a phenomenon called jetting can arise, this will make the crossette propel through the skies like a go-getter star, while this also is a very cool effect, it’s not as fun when it’s not the effect we want to obtain. But think rationally, if you are making 2 inch crossettes you have to tweak the break accordingly.
I am not going to go through the safety and mixing procedures behind making flash powder, I expect you are familiar with that before attempting to do so.

Posted Image

You are now ready to fill the cavity with your desired break charge, but before you do so please look at the picture of the crossette pump in the beginning of the guide. Hopefully you can see that little pin in the end of the tool, when we made the crossettes earlier this little pin made a little hole inside the bigger X shaped cavity. This hole should be filled with granulated black powder, you can use a short piece of blackmatch or Chinese paper fuse instead, but black powder might be the easiest. This is also to prevent jetting which we talked about earlier.
As you know for sure flash powder emits a huge amount of light. In some cases this can make the effect barely visible, a good advice is to add a fairly little amount of black powder to the breaking charge to subdue the strong light. This will also aid in making the charge a bit more “fluffy” .
You are now ready to make the cap, cut out a circle of carton with the same diameter as the crossette and glue it into place with some glue. If you are using a glue gun, make sure to unplug it before use. Fireworks and electricity simply don’t fit together.

Posted Image
Almost finished now, the only thing remaining is to cover the sides with some paper or melted wax. I haven’t tried wax yet, but gummed paper tape will do the job with great results. Just make sure to cover it very well so it can’t take fire from the sides.

Posted Image

As you probably know you don’t have to prime tiger tail stars, but since the surface tends to be very smooth I would suggest to just prime it with a small amount of granulated black powder to make a rougher surface. If you use other formulas you have to prime accordingly.
Just one thing to say now, hope you’ve learned something :-)
  • Pyrophoric likes this

#2 Bobosan

Bobosan

    Firebreather

  • Donator
  • PipPipPipPipPip
  • 1,142 posts
  • Gender:Male
  • Location:Indiana
  • Interests:pyrotechnics, electronics, collectable firearms, women....but not necessarily in that order!

Posted 22 January 2013 - 09:07 AM

Looks like tedious work with smaller crossettes. Nice tut...thank you.

#3 mathiasxx94

mathiasxx94

    Playing with fire

  • Full Member
  • PipPip
  • 46 posts
  • Gender:Male
  • Location:Norway
  • Interests:Pyro, Chemistry, amateur experimentalism, physics

Posted 22 January 2013 - 11:19 AM

Thank you! Yes it is a bit tedious especially when making a lot of them, but I like that I can make small ball shells with crossettes.

#4 swapnilsutar1988

swapnilsutar1988

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 528 posts
  • Gender:Male
  • Interests:Playing with fire,Pyrotechnics.
    Learning new pyro related stuffs, Chemistry, Aerial shell.

Posted 22 January 2013 - 11:50 AM

overall tutorial was nice..
Any special reason for adding 7g of atomized(what mesh?) aluminium in TT composition?

:)  :)  :)  :)  Never forget the people who asked
you to give up, so that you can
remember to call them to your success
party and make them eat up their own
words..............
:) :) :) :)


#5 mathiasxx94

mathiasxx94

    Playing with fire

  • Full Member
  • PipPip
  • 46 posts
  • Gender:Male
  • Location:Norway
  • Interests:Pyro, Chemistry, amateur experimentalism, physics

Posted 22 January 2013 - 12:20 PM

The aluminium (250# atomized) was an attempt on spicing up the formula, it did not really show up in the video here, don't know why. But I made some stars for NYE with this formula and the effect was pretty cool, sort of delayed silver flashes in the tail.

#6 AlexPyro66

AlexPyro66

    Pyromaniac

  • Full Member
  • PipPipPip
  • 117 posts
  • Gender:Male
  • Location:Greece

Posted 22 January 2013 - 02:05 PM

Great tutorial and I was ready to buy a crossette pump very helpful
  • Andrewlewallen likes this

#7 vegasdude

vegasdude

    Playing with fire

  • Full Member
  • PipPip
  • 34 posts
  • Gender:Male

Posted 22 January 2013 - 10:26 PM

Thanks for the Tutorial. Now I got to order a crossette pump...

Edited by vegasdude, 22 January 2013 - 10:28 PM.


#8 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,470 posts
  • Gender:Male
  • Location:Above You

Posted 22 January 2013 - 11:01 PM

Please do note that crossette pumps made by the common US toolmakers will have a much smaller cavity. They're the original design that those chinese brass pumps are based from initially. They're more likely to jet, but also much harder to overbreak. They may also come in round hole instead of fluted or cruciform cavity.

By the way, filling in the bottom of the cavity with a fine grained powder is called "tacking" the crossette. After you add it, lightly consolidating the grains will lock them into place, while maintaining fire paths. I'd recommend something fairly fine like 7FA or 4Fg (same size) which is -40+100 mesh. I normally just use the dust remaining after granulating and grading.
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#9 Zingy

Zingy

    Pyromaniac

  • Full Member
  • PipPipPip
  • 55 posts

Posted 23 January 2013 - 12:29 PM

Many of us old timers, started off using the crossette pumps made with the cylinder cavity, for a 'shot'. The 'shot' was basically a short, fat, hand made, fire cracker, with a short black match fuse. The 'shot' prevented the jetting, and also gave a larger spread, for the break of each crossette comet. However, the four sided fluted cavity pumps gave an awesomely admired, four sided symmetrical break, for each crossette comet, converting many of us, doing pyro for decades.

Edited by Zingy, 23 January 2013 - 12:35 PM.


#10 AlexPyro66

AlexPyro66

    Pyromaniac

  • Full Member
  • PipPipPip
  • 117 posts
  • Gender:Male
  • Location:Greece

Posted 24 January 2013 - 06:50 AM

I will try to make a 1'' crossete pump with the four sided cavity.Is it a problem if the cavity is out of wood?

#11 AirCowPeacock

AirCowPeacock

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 555 posts

Posted 24 January 2013 - 09:35 AM

I think you will have trouble with it sticking. If you do, make it smooth and sealed.

#12 mathiasxx94

mathiasxx94

    Playing with fire

  • Full Member
  • PipPip
  • 46 posts
  • Gender:Male
  • Location:Norway
  • Interests:Pyro, Chemistry, amateur experimentalism, physics

Posted 24 January 2013 - 09:39 AM

Alex: I actually tried to make one out of wood before I bought the pump, but I found it pretty hard to work with. The comp was always sticking to the tool, however some lacquer might solve that. But you also got the problem with symmetry of the cavity former, I used a handheld Dremel to make it and the result was not very good. If you got the right tools it might work, but I would suggest to buy one, they are not that expensive.

BTW: Thanks for the additional info Mumbles, and Zingy

I would like to get an extra cylinder "tip" for the pump to change between crossettes and cavity stars.

#13 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,470 posts
  • Gender:Male
  • Location:Above You

Posted 24 January 2013 - 11:22 AM

There are people who make such a tool if you're ever interested. They come with tips to make crossettes, cavity comets, and flat comets. I've been thinking about getting one to do both round and fluted crossettes, as well as cavity comets, and flat comets.
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#14 AlexPyro66

AlexPyro66

    Pyromaniac

  • Full Member
  • PipPipPip
  • 117 posts
  • Gender:Male
  • Location:Greece

Posted 24 January 2013 - 11:52 AM

Alex: I actually tried to make one out of wood before I bought the pump, but I found it pretty hard to work with. The comp was always sticking to the tool, however some lacquer might solve that. But you also got the problem with symmetry of the cavity former, I used a handheld Dremel to make it and the result was not very good. If you got the right tools it might work, but I would suggest to buy one, they are not that expensive.

BTW: Thanks for the additional info Mumbles, and Zingy

I would like to get an extra cylinder "tip" for the pump to change between crossettes and cavity stars.

Yes wooden propably be good for crossettes.I know that crossete pumps are cheap but here in greece if you want to buy any kind of pyro tools you will have to pay at least 45$ for the shipping so they are a litle pricie.Ok another idea i have an aluminium foundry can i make a wooden prototype and cast it?

Edited by AlexPyro66, 24 January 2013 - 11:53 AM.


#15 MrB

MrB

    Firebreather

  • HE Qualified
  • PipPipPipPipPip
  • 1,748 posts
  • Gender:Male

Posted 24 January 2013 - 10:35 PM

Wolter Pyro Tools has these "quad pumps" for making Crossettes. Since this is the FAQ/Tutorial for Crossettes, does anyone care to elaborate on the design, and it's advantage?

I guess your supposed to take the 4 parts, hold em together, TIGHTLY, somehow, seal one end, add break, and seal the other end, and remove whatever held em together, leaving the sides exposed.But wouldn't this make for a crossette that is very easy to blow apart when the shell breaks, not to mention that even if it holds together, the "cracks" where the 4 parts join up will be fairly lose, the only thing holding them together being the end covers...
I just don't get it, does anyone use these and care to do a little show and tell? (I probably got something about the use of these wrong, there might be something obvious i'm missing. Wouldn't be the first time i'm proving myself not to be half as bright as i like to think i am.
B!

#16 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,470 posts
  • Gender:Male
  • Location:Above You

Posted 25 January 2013 - 12:13 AM

I will start this off by saying I really want a quad pump. Quad pumps, while able to make a crossette type of effect, is not actually designed to do so. They're used to make quadrant inserts, as shown in the following videos.

2 sets of 4 inserts are placed 45 degrees off set from one another and rolled up in a few turns of kraft. The center cavity is fused and filled with burst. Typically BP augmented with flash is used due to the limited space. Then you close it up, spike and paste as normal.




Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#17 californiapyro

californiapyro

    Pyrotechnician

  • Full Member
  • PipPipPipPip
  • 681 posts
  • Gender:Male
  • Location:cali
  • Interests:metalwork, pyrotechnics, rocketry, tooling

Posted 25 January 2013 - 01:21 AM

alex, just so you know, I can ship anywhere in the world on some items for as little as $15. I am sure other suppliers can do the same :) Just gotta ask
www.fireworktools.com

Check it out! Quality tooling at an affordable price

#18 MrB

MrB

    Firebreather

  • HE Qualified
  • PipPipPipPipPip
  • 1,748 posts
  • Gender:Male

Posted 25 January 2013 - 06:58 AM

Ah, so while they are crossettes, they aren't self-contained, and you simply make a shell with a set, or a few offset sets. Duh, that wasn't so hard to figure out, now that you've pointed it out.
B!

Edit
I'm pretty sure i've even seen the effect in action, but never linked the two together. Some days, things just don't go well. But do these days have to stack next to one and other, for years on end?
/Edit

Edited by MrB, 25 January 2013 - 07:04 AM.


#19 Mumbles

Mumbles

    Grandmaster

  • Admin
  • PipPipPipPipPipPipPipPipPipPip
  • 11,470 posts
  • Gender:Male
  • Location:Above You

Posted 25 January 2013 - 10:42 AM

They're really not very common. I've never actually seen one in person. I've only seen that video, and read some description of them in Hardt as well as some description from Mike Swisher. That doesn't mean I don't want the tooling though. Farfalle weren't very common when a few of us started making them 6 years, and now look at them.

Mathias, have you done any comparisons between weighing out the composition for each comet and just trimming the length with the pin on the tooling? While it goes against reason, I've been told that trimming gives a more accurate effect.
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#20 Algenco

Algenco

    Firebreather

  • Donator - HE
  • PipPipPipPipPip
  • 1,114 posts
  • Gender:Male
  • Location:KY

Posted 25 January 2013 - 01:43 PM

Mumbles, I want the quad pumps too, maybe we can get a group buy :)
Old Fart

BPG,HPA, PGI





Also tagged with one or more of these keywords: tutorialguide, crossette, crossettes, how to, splitting comets, splitting comet

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users