Cubic Stars using a light diffuser

[Umphrey]

Inspiration from Best of AFNIII pg 124 article "CUT STARS - - - WITHOUT CUTTING"

 

You will need:

1 'eggcrate' fluorescent light diffuser. --Can be found in any hardware store, usualy in the lighting section.

Several plaster putty knives

Atleast 100 grams star composition

 

First a word about light diffusers, they are made by an injection molding process, every hole's wall will have a very slight incline--this is an artifact of the injection mold method, it is done to facilitate the extraction from the mold.

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Diffuser1.jpg

 

That said, the first thing we must do is orient the light diffuser, we want it oriented so that the stars are unable to fall through whilst they dry, so we mark a "faceup" and "facedown" on the light diffuser, we want the widest point facing up and the narrowest point facing down. When the stars are no longer feeling wet, simply flip the whole light diffuser over and give it a tap--most stars should fall out then, if they don't you can gently push them out with a finger.

 

 

Now the preparation of the star composition.

 

For this tutorial I am making 1kg spider stars

Formula:

Potassium nitrate 54%

Charcoal 32%

Sulfur 7%

Dextrin 7%

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Compositionpile1.jpg

 

Place MOST of your composition in a container, begin misting it with a solution of 80/20 water/alcohol until is it is evenly moist, it should just hold together as a solid lump when squeezed in your hand. If you over wet it, simply add more composition and knead it in. Cut stars use slightly more solvent than pumped or rolled stars, but only by a very SLIGHT amount.

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Compositioninbowl.jpg

http://i176.photobucket.com/albums/w194/Umphrey_APC/MistBottle.jpg

 

It is now time to spread the star composition into the light diffuser, Place your light diffuser on a flat newspaper covered table, add all of your composition to the middle of the light diffuser, mash it down using one putty knife, then rake across it with another putty knife, forcing and compressing the composition evenly into the holes.

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/PICT9203.jpg

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/PICT9208.jpg

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/PICT9212.jpg

 

Now we allow the stars to dry on the table overnight. After 24 hours the light diffuser should be supported so that it is several inches off the table, this is so both exposed sides of the star can dry. Stars can fully dry inside the light diffuser, but this takes quite some time. To speed things up the stars should be allowed to dry for 48 hours in the raised position, the light diffuser can then be flipped over and allow the stars to fall free. These stars will still be moist inside and require an additional day or two to fully dry.

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Raiseddiffuser.jpg

 

NOTE: The stars pictured drying are from an earlier batch of flitter stars

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Sundrying.jpg

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Starscloseup.jpg

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Sizecomparedtohand.jpg

 

http://i176.photobucket.com/albums/w194/Umphrey_APC/Sizecomparedtoquarter.jpg

 

Any star that uses water or alcohol solvents can be used in the light diffuser. Stars that use an acetone or MEK solvent should not be used, it will disolve the light diffuser.

 

Video depicting the process:

[moonshot]

Very innovative idea! Runs along the same lines as a star plate but much easier and cheaper. Now thats amateur pyro at its best. If your making that many stars you must be into aerial shells or larger rockets. Hope you can post some vids of your stuff. Great idea. I will try it.

[mormanman]

Great idea!

[flying fish]

Holy Crap, I just finished a frustrating lab for a Modern Physics course involving a grating spectrometer. And now you want me to use a giant light diffuser and not have nightmares about it?!

 

Actually, that is a brilliant idea. I love how uniform those "cut" stars are. The best thing will be claiming you cut them normally when your pyro friends see them.

[crazyboy25]

very nice innovative and inventive too what arte the demnsionas of the stars?

[tentacles]

I think most diffusers are 1/2"x1/2" - I've seen them up to 4" though.. It's possible some company makes smaller ones, a 1/4" one would be great.

 

Also, you could use a rolling pin if your comp likes to be compressed in a bit.

[bmarley5780]

I have actually seen this done on another web page.

 

They point out that 2 can be glued using XXXXXXXX (glues plastic shells)

 

and then you would have a 1"x1" star.

[qwezxc12]

I read on rec.pyro that someone used Xylene and applied it with a paint roller to the diffusers to glue two together to make 1/2" x 1/2" x 1/2" cubes. It sounded like a good idea, but if the grating is tapered from the mold as you say, I don't know how you'd manage to get your stars out intact after gluing two diffusers together...

[bmarley5780]

This is this site I saw it on...

-Same thing as qwezxc12 said.

 

http://www.wichitabuggywhip.com/fireworks/misc.html#hsr

[Umphrey]

Yes, I had the idea of stacking two light diffusers together, but it appears too difficult to align and the tapered sides would cause the stars to jam. I have indeed used a plastic rolling pin for compressing the stars, it works quite nicely.

 

After further research, it seems there are two types of light diffusers available, the injection molded type and a plastic welded type. The welded type seems to be far more common, but it feels much more flimsy. I would think the plastic welded variety could be stacked together.

 

very nice innovative and inventive too what arte the demnsionas of the stars?

Thanks.

The stars measure 1/2" by 1/2" by 3/8" thick.

Almost all of them come out perfectly uniform, except for the few on the very edges.

 

I have seen various sized light diffusers available. I have measured them roughly as 3/8 by 3/8 by 1/4" thick and 5/8 by 5/8 by 1/2" thick.

 

If your making that many stars you must be into aerial shells or larger rockets. Hope you can post some vids of your stuff. Great idea. I will try it.

I primarily do 2" and 3" canister shells and star mines. I will hopefully have a decent video camera for documenting them soon. Can anyone recommend a good pyro camera in the 200 to 300 dollar range?

[FrankRizzo]

Just get a pocket-sized Canon SD1000 digital camera. Its movie mode will do 640x480 @ 30FPS for many minutes if you have a large memory card. It'll also do high-speed 60FPS at the lower 320x240 resolution.

 

Buydig.com - $207

Newegg.com - $219

[frogy]

Great tutorial... I don't mass produce stars like this yet, so it only adds to my knowledge since I probably won't be making them like this =)

 

==============================

 

Jimmy Yawn uses a Aiptek MPVR for his "Rocket camera"

 

It does 640 x 480 upto 30 fps in VGA mode and it's only about $100

 

http://www.aiptek.com/Merchant2/merchant.m...1&Store_Code=AS

 

 

I'm going to get that or something similar when I get some cash to spend =) (aka sell excess chemicals to friend)

 

My friends have modded those $10-20 "disposable ('one time use')" movie cameras they sell at Wall-Greens to be reused over and over... They have at least a 320 x 240 resolution...

 

Here's another cheapo

http://www.newegg.com/Product/Product.aspx...N82E16830125001

 

It does 640x480 in VGA and it's $70... Only has 256 MB built-in, non expandable so it only does 30 minutes... (plenty for me though)

 

Here for $110 you get 640x480 | 30 FPS and a rechargable battery, charger, tripod, etc...

http://www.newegg.com/Product/Product.aspx...N82E16830241010

[moonshot]

Yes, I had the idea of stacking two light diffusers together, but it appears too difficult to align and the tapered sides would cause the stars to jam. I have indeed used a plastic rolling pin for compressing the stars, it works quite nicely.

 

After further research, it seems there are two types of light diffusers available, the injection molded type and a plastic welded type. The welded type seems to be far more common, but it feels much more flimsy. I would think the plastic welded variety could be stacked together.

 

very nice innovative and inventive too what arte the demnsionas of the stars?

Thanks.

The stars measure 1/2" by 1/2" by 3/8" thick.

Almost all of them come out perfectly uniform, except for the few on the very edges.

 

I have seen various sized light diffusers available. I have measured them roughly as 3/8 by 3/8 by 1/4" thick and 5/8 by 5/8 by 1/2" thick.

 

If your making that many stars you must be into aerial shells or larger rockets. Hope you can post some vids of your stuff. Great idea. I will try it.

I primarily do 2" and 3" canister shells and star mines. I will hopefully have a decent video camera for documenting them soon. Can anyone recommend a good pyro camera in the 200 to 300 dollar range?

I use a samsung S500 in movie mode to capture my homemade fireworks. Runs around 150.00 or cheaper. Need the memory card to get decent video time.

[d4j0n]

if you're looking for 200-300 range, get one of the cannon powershots. Great quality avi video and can record at high 640x480 resolution.

[Bonny]

These work great! Not sure where I first read about this idea...I usually make smaller batches, so I have some pieces of this that have been cut to make 50 or 100 stars at a time, and I do use a rolling pin to compact the comp into the holes.

[Yankie]

I found some 1/2" x 1/2" x 1/2" non tapered light diffuser from a fluro light, I could only get a peice 10" by 6". I found it a tad difficult to press all the star mixture in but I suppose that has to do with the small scale. The stars came out really easy and look great, perfect cubes with rounded edges. They will be great in 4"ers and as small rising comets. I will look for some smaller screens, my dad says he has seen them smaller. Edited January 12, 2009 by Yankie

[optimus]

Don't suppose anyone has an idea where to source these in the UK - they don't seem to be readily available. A quick google points towards lots of other random hobbyists struggling to find the stuff in the UK

[Yankie]

Heres a picture of the stars I was describing before.

[Bonny]

Don't suppose anyone has an idea where to source these in the UK - they don't seem to be readily available. A quick google points towards lots of other random hobbyists struggling to find the stuff in the UK

 

Not sure about in the UK, but I'd start by looking in large hardware stores, if not then try specialty lighting shops that deal with commercial/industrial lights.

[Swede]

Here's a thread from the dead that is really useful... I never would have seen it otherwise. Neat idea! I bet the edges of these stars ignite easily, and being blown blind is rarely a problem.