How to Make Stars Using a Star Pump
There are a bunch of ways to make fireworks stars. Each method has its advantages, so there really isn't a best or right method to use for all the stars you need. On the contrary, it's a good idea to learn all of them, so that you have more options.
For me, the humble star pump serves several purposes.
But it is most useful to me in testing new star comps. With any new star that I'm going to make, I go through a pretty consistent set of steps in testing the new star. I usually make up 10 or 20 grams of the new mix to start with. (I learned the hard way NEVER to commit to a full batch of comp. Too many chemicals wasted that way.)
First step, I simply burn a about a teaspoon-sized pile of the new mix--loose powder--on my special, fancy-dancy, flat rock on fence post dedicated to just burning star comps. I look at it burn: does it burn approximately the color I want (a pile of comp, seen up close, is not gonna look like a star 200 feet in the sky)? Does it light okay? Does it burn fast or slow? I just watch it to see if there are any deal-killer problems.
Next, I pack some of the comp into a lance tube (thin wall, about the size of a cigarette), and burn that and toss it into the air to approximate what a star might look like.
Next, I'll pump a few stars, let 'em dry, and fire them outa my star gun. If those look good, and I've overcome any priming issues, I pump some more stars and make a 2or 3-inch shell and test that.
You get the picture...
Now, there are other situations where I find pumped stars useful, too. And of course, you simply cannot get a piece of star-making equipment as cheap as a star pump, so there's real economy involved.
As usual, this is another great project from Ned which makes the whole process of pumping stars clearer and easier than ever.
Making Fireworks Stars with a Star Pump
By Ned Gorski
Charcoal Streamer and Titanium Streamer 1.75-Inch Star Mines
Most fireworks devices that create an aerial display depend on fireworks stars to produce their effects. Examples include:
- Roman candles
- Multi-tube "cakes"
- Rising tails on aerial fireworks shells
- Aerial shells
- Fireworks mines
- Rocket headings
- Single-shot comets
Fireworks stars can be made by various processes.
- Cut stars. Skylighter's newsletter has featured "Wonderful Zinc Stars" which were made with the "cut star" method.
- Rolled stars. These are rolled into round balls. Starting with a small core, a composition of mixed chemicals is rolled onto the core to slowly increase the size of the "rolled star."
- And there are other methods as well.
This method of pumping stars one at a time is perfect for beginners. It is about the easiest and simplest way to make stars. It requires only very basic equipment and one inexpensive pyro tool-the star pump.
This project will show you how to make homemade pumped stars which are suitable for use in any of the fireworks devices above. Pumping small quantities of charcoal, glitter, or color stars is the best way I know to make a few stars of just the right size to use in these projects.
Advantages of Pumped Stars
Fast drying time. One real, significant advantage of pumped stars is that a relatively dry composition is used. The resulting stars will dry quickly. The stars can be pumped one day, dried overnight, primed the next day, dried again overnight, and used in devices the following day. This really speeds things up.
Ease of ignition. Pumped stars have sharp edges at each end. These edges facilitate ignition and burning of the star. For this reason, some pumped stars do not require priming after they are pumped. But priming never hurts anything. So when in doubt, prime the stars.
- Uniform size. It is relatively easy to prepare a uniformly-sized batch of stars. Such stars exhibit a consistent burn time, which makes for a pleasing display. Cylindrical, pumped stars also fit nicely into an aerial shell casing.
Pumped and Primed Stars Filling Shell Hemispheres
Tooling for Pumped StarsTwo common types of star pumps are the single-star pump, and the star-plate gang pump which pumps numerous stars at once.
1/2-Inch Star Pump and 1/2-Inch Star Plate from Skylighter
The star plate can quickly make large numbers of stars out of bigger batches of composition. Go to this link for more information on using star plates.
This project, however, is about using single-star pumps. The single-star pump is an economical tool which can be used to turn small amounts of star composition into stars of uniform shape and size.
This method comes in handy for quickly making a few stars for testing or for small projects. Using a single-star pump, it is a simple matter to turn a batch of star composition into just the right number of stars for a chosen project.
Single-star pumps from Skylighter come in two basic varieties, the economy pump and the standard pump. Each variety is available in a range of sizes (diameters).
Economy Star Pump and Standard Star Pump
There are some significant differences between these two styles of pump in the way they are made and used. They will be addressed individually in the pumping-stars sections below.
Pumping Gold Glitter StarsFor this particular project, a tried-and-true, very pretty, gold-glitter star formula known as "D1" will be used. We will make a four-ounce (115 gram) batch of this composition and then pump it into stars.
After you've gotten your hands dirty and you have your first batch of pumped stars under your belt (and in the air!), I will provide some bonus material. This will include
- formulas for some other good compositions to use for pumped stars,
- an explanation of how to determine the appropriate batch size to yield just enough stars for a given project,
- an explanation of how to calculate the correct amounts of each chemical to use to yield a certain batch size, and
- notes on priming stars.
D1 Gold Glitter Star Formula
|Component||Percent||Factor||4 oz||115 g|
|Potassium nitrate||53%||0.53||2.1 oz||61 g|
|Sulfur||18%||0.18||0.7 oz||20.7 g|
|Charcoal, airfloat||11%||0.11||0.45 oz||12.7 g|
|Aluminum, atomized||7%||0.07||0.3 oz||8 g|
|Sodium bicarbonate||7%||0.07||0.3 oz||8 g|
Note: The atomized aluminum should be approximately 325-mesh, 20-micron. Skylighter #CH0116 is used in this project. But most 325-mesh atomized aluminums, with average micron size in the 12-32 micron range will work.
Note: This comp will be dampened with +10% (0.4 oz/11.5 g) water.
Note: +10% spherical or sponge titanium particles, 80-mesh or coarser, may be added to this glitter composition to create a delayed, falling silver-spark trail behind the glittering head of each star. Be sure to see the discussion in the bonus material below regarding metal additives if you decide to try this.
Grinding ChemicalsNote: If you have a ball mill, it offers you a much easier and simpler alternative to grinding individual chemicals and screen-mixing the composition as discussed below. Instead, you can ball mill all the chemicals except any metals (which would be added after the milling) together as shown in the ball milling tutorial and making black powder tutorial.
If you won't be using a ball mill, perform the following steps.
Verify that the non-metal chemicals are granulated finely enough that they will each easily pass through a 40-mesh screen. The easiest and safest way to do this is to mill them individually in a blade-type coffee mill or in a single serving blender, the kind of blender is being used in this project, and which runs about $20 at Walmart.
Warning: If you need to grind/mill chemicals, do not mix them before using the blade-type grinder or blender. Only grind individual chemicals, one at a time. Clean the cup out thoroughly between chemicals. Never mill metal particles.
Pulverizing Chemical in a Blade-Type Mill
Weighing and Mixing the ChemicalsWhen all chemicals are finely ground, weigh each chemical individually into an empty paper cup according to the quantities required for a 4 ounce (115 g) batch as indicated in the chart above. Put all of the weighed chemicals (NOT INCLUDING any coarse metal particles you may intend to use) together in a mixing tub. Weigh the complete composition to make sure the total batch weight is what is shown in the formula above, 4 oz (or 115 g). This verifies you made no mistakes during the weighing.
After you have confirmed the correct weight, put the lid tightly on the tub. Shake the tub to mix the composition thoroughly while holding the lid on tightly.
Screening the CompositionWorking outdoors, screen the mixed chemicals twice through the 40-mesh screen to break up any clumps and to thoroughly mix them.
Return the composition to the mixing tub. With the lid held tightly on the tub, shake the composition in the mixing tub again.
If hard metal particles such as ferro-titanium or titanium are going to be used in the star composition, add them now into the mixing tub. Give sealed mixing tub one more good shake.
Dampening the CompositionDampen the composition until it just stops being free-flowing by spraying water a little bit at a time into the mixing tub as you knead the mixture with gloved hands. The dampened composition should end up feeling like brown sugar-able to be clumped in a ball in your fist, but also able to be broken apart easily.
It is a good idea to have the mixing tub on the scale as you spray the water into it, so that you can monitor the weight of the water. Typically, charcoal compositions, such as the D1 glitter composition, require a total amount of water approximately equal to +10% (+0.10) of the non-metal weight of the composition. So, if you started with 4 ounces of composition, adding about 0.4 ounces of water should wet it correctly for pumping.
Note: If you use more water than needed, the composition will become too sticky and will be hard to work with. The pumped stars will also take much longer to dry, and may not dry completely in their centers. Too little water, on the other hand, will result in pumped stars which will crumble when they are ejected from the star pump.
Use gloved hands to mix the water thoroughly into the powder. Shake the composition in the closed container. Then pass the mixture through a 20-mesh screen several times to thoroughly integrate the moisture.
When finished, return the composition to the mixing tub. If you do not plan to pump stars immediately, cover it tightly.
Adding Water to Composition, and Working It through a 20-Mesh Screen to Completely Mix In the Moisture
Pumping StarsPumping stars requires the correct tools and skills. A solid non-sparking mallet, a ramming post, a solid base on which to pump the stars, and a star pump are necessary. In addition to those implements, you'll need the tub of dampened composition and a paper plate or drying screen onto which to put the pumped stars.
Implements Needed to Ram Single Stars
The base on which the stars are rammed should be solid, hard, non-sparking, and durable. A wood surface will quickly become dented during the star-ramming. An aluminum surface is ideal. A piece of hard kitchen countertop material or a plastic cutting board might suffice.
Solid Aluminum Bases on which to Pump Stars
It takes practice to get comfortable pumping stars, and it can become a bit tedious if you're making a lot of them. So, work with relatively small quantities, at least in the beginning. If you want to take a break during the star pumping, simply seal the container of dampened composition so it doesn't dry out, and come back to it later.
Using an Economy Star PumpThe economy star pump has a rammer which slides up into a sleeve from the bottom.
Economy Star Pump Ready to Use
Hold the rammer all the way up inside the sleeve. Plunge the pump into the damp star composition to fill the empty space. Wipe off any excess comp sticking out beyond the end of the star pump. Ram the star with 3 or 4 blows of the mallet. Press on the rammer to eject the star onto a drying screen or paper plate.
Repeat the process to produce as many pumped stars as desired. Once you get into the hang of it, the pumping goes nice and quickly.
Filling Star Pump, Ramming and Ejecting Star
Pumping Stars with a Standard Star PumpThe rammer of a standard star pump has a pin sticking out of its side. The rammer slides down into the sleeve from its top. The top of the sleeve is identified by the presence of a slot which accepts the pin on the rammer.
The pin on the rammer is designed to allow excess star composition to be trimmed off the end of a rammed star before it is ejected. Properly done, this will result in rammed stars that all have exactly the same length.
Standard Star Pump Ready for Use
Hold the rammer's pin about 3/8-inch above the top of the sleeve as shown below. Plunge the pump repeatedly into the dampened composition to fill it as full as possible. Wipe the excess comp from the end of the filled pump.
Filling a Standard Star Pump with Composition
Ram the composition solid with 4-5 solid blows of the mallet. Observe the rammer's pin carefully to ensure that it does not come into contact with the pump's sleeve. This is very important to prevent damaging the pump.
Ramming a Star with the Standard Pump
Push the rammer into the sleeve until the pin contacts the top of the sleeve. Trim off the excess rammed star composition that is projecting beyond the bottom of the sleeve with a knife.
Trimming Off Excess Star Composition with a Knife
Rotate the rammer until the pin is aligned with the sleeve's slot. Press the rammer so that the pin slides down into the slot in the sleeve and the pumped star is ejected from the bottom of the sleeve. All the stars made this way will have the exact same length.
Ejecting a Trimmed Star
Drying StarsThese pumped stars do not have much water in them, so they dry quickly. They will dry best in a location which has warm, dry, moving air. It is best to place the stars on a screen so that moving air can reach all sides of each star.
A drying chamber is ideal for drying stars. In such a box, the stars will dry overnight.
Many folks use a food dehydrator to dry stars. This must be done in a safe place, because this is an electric device which can malfunction and cause a fire. Line the trays of the food dehydrator with fiberglass screen to prevent stars or debris from falling to the bottom of the unit.
You can also simply leave the stars on a paper plate in a warm, breezy, safe location, and they will dry quickly.
Drying Your Stars
Priming StarsTo ensure reliable ignition of the stars and fast propagation of the flame to the whole surface of each star, prime them with a black powder prime composition.
Black Powder Star Prime
|Component||Percent||Factor||4.2 oz||126 g|
|Potassium nitrate||75%||0.75||3 oz||90 g|
|Charcoal, airfloat||15%||0.15||0.6 oz||18 g|
|Sulfur||10%||0.10||0.4 oz||12 g|
|Dextrin||+5%||+0.05||+0.2 oz||+6 g|
Note: This batch of prime will be approximately enough to prime 16 ounces of stars. Use about 1 ounce of prime per 4 ounces of dry stars.
Place a batch of dry, pumped stars in a plastic bowl. Lightly spray the stars with water, then "swirl" the stars in the bowl as a teaspoonful of the prime composition is dusted on them.
Repeat these steps, without getting the stars too wet, until an amount of the prime equal to one ounce of prime per 4 ounces of stars has been applied to the stars. Now that the prime has been applied, dry the stars once again.
Spraying Stars with Water, and Applying Black Powder Prime
Your stars are now finished and ready to use in your choice of devices. Git on out there and shoot something!
The pictures and video below show how these glitter stars-both with and without the added titanium-look in the sky when fired in 3-inch mines.
Gold Glitter and Glitter/Titanium 3-Inch Mines
Ok, that concludes the basic project. Now, here's some more good stuff I promised earlier.
This additional material will help you move on to create a wide variety of beautiful pumped stars.
Other Formulas Suitable for Pumped StarsJust about any water/dextrin bound star composition can be made into pumped stars.
The following chart of common charcoal streamer compositions presents a wide variety of possible star effects while only using a small number of simple chemicals.
The names of the star compositions are abbreviated in the chart. The full names are Chrysanthemum 6 (C-6), Chrysanthemum 8 (C-8), Tiger-Tail (TT), Tiger-Willow (TW), and Willow (W).
Note: Numbers in parenthesis are the corresponding "factors" for use as in the formula charts above.
You can see from the formula chart that the percentage of the oxidizer, potassium nitrate, decreases by about 5% in increments from Chrysanthemum 6 through the other star compositions to Willow.
As the percentage of oxidizer decreases, the percentage of fuels-sulfur and charcoal-increases.
Each decrease in the potassium nitrate oxidizer slows the formula down, causing the resulting stars to burn more slowly. Chrysanthemum-6, for example, is a very fast-burning star. It is suitable for fireworks mines like those shown in the video at the beginning of this article, or for fast-displaying spider web aerial shells.
Willow, on the other hand, is a long-hanging, very slow-burning star, wonderful for aerial shells. The size of Willow stars must be dialed in very carefully to ensure they burn out before hitting the ground.
The burn speeds of the other formulas gradually decrease from Chrysanthemum 6 to Willow.
Adding MetalsAn even wider variety of star effects can be created by adding coarse metal particles to these compositions to create spark effects. Metal particles may be added to these charcoal-star compositions in percentages anywhere from 5% to 30%, with 15% being a common starting point.
Adding titanium granules will create the effect seen in the second mine in the video at the beginning of this project. Adding ferro-titanium, or a mix of titanium and ferro-titanium, will create other unique metal-spark effects.
Warning: If hard metal particles such as titanium or ferro-titanium are to be included in the composition, the particles should be no smaller than 80-mesh. Hard metal particles smaller than 80-mesh and larger than about 200-mesh are likely to damage the pump by binding in the space between the rammer and the sleeve.
Sifting metals with an 80-mesh screen can be quite a challenge. The small openings in 80-mesh screen clog up quickly and often permanently.
So never use an expensive pyrotechnic screen to sort metal particles. Save your good screens; buy a cheap 40-mesh kitchen colander instead, and use only the (+40 mesh) granules which will not pass through that screen. This provides a safety factor in particle size to prevent damage to your star pump and is a good way to save your pyro screens for other more important purposes.
For more information on metal particles and mesh sizes see these Skylighter tutorials:
- How Particle Size and Shape is Defined
- Understanding Metal Powder Particle Size and Shape
- Understanding Mesh Sizes and Microns.
How Much Star Composition Should You MakeHere are some approximate quantities of charcoal-streamer or glitter stars that various fireworks devices require.
Quantity of Stars in Some Fireworks
|Device||Required Quantity of Stars|
|1.75-inch mine||1.25 ounces of stars|
|3-inch aerial shell||1.8 ounces of stars|
|4-inch aerial shell||4.5 ounces of stars|
So, for example if one wants to make, say, a 4-inch shell and two 3-inch shells with the stars that are going to be pumped, 8 ounces of star composition should be sufficient.
Note: Metal particles add weight to a star, but not much volume. For that reason, the above approximations are based on star-composition weight without metal particles added. So, for instance, a 4-inch shell with metal-spark stars would use 4.5 ounces of star composition before any metal is added to it.
How to Determine Amount of Each Chemical to Use per Batch SizeLet's say we want 8 ounces of Tiger Tail stars. We will simply multiply 8 ounces by the decimal factor in the formula to get the weight of each ingredient that will be needed.
- Potassium nitrate, 8 x 0.44 = 3.52 ounces
- Airfloat charcoal, 8 x 0.44 = 3.52 ounces
- Sulfur, 8 x 0.06 = 0.48 ounces
- Dextrin, 8 x 0.06 = 0.48 ounces
If an additional 15% (+ 0.15) titanium is desired for a metal-spark effect, 0.15 x 8 = 1.2 ounces of +40 mesh metal powder would be added.
And, in practice, because many digital scales are precise only to 0.05 or 0.1 ounce, the above quantities can be rounded off to the nearest 0.1 ounce. 3.52 can be rounded off to 3.5 ounces, and 0.48 can be rounded off to 0.5 ounce. The weight will still total 8 ounces.
So, in this example we'll be working with 8 ounces of Tiger-Tail composition or 9.2 ounces of Silver-Spark Tiger-Tail composition (which has had the metal particles added to it).
How to Tell if a Star Needs Priming
Some stars, especially those with high oxidizer content like Chrysanthemum-6 and 8, do not require priming when they are used in most devices. Other stars, like the low-oxidizer willow stars, may not ignite reliably, or they may burn too long if they are not primed because the flame does not propagate over their entire surface quickly.
One way to determine if a batch of stars needs priming is to test fire them out of a star gun after they dry. If a star will light and perform well when it's been strongly fired from a star gun, you can figure it will do well in a fireworks device.
Check out these tips on using a star gun. If you don't have a fancy welded star gun like the one in my article, you can make a simple one using a paper tube mounted on a wooden dowel.