Large Reloadable Glitter Comets
Take just 20 minutes to read this article, print it out, and use it to make this firework. You will be amazed at how well it will work as long as you follow the steps we give you here. Try this project today and see if you don't agree.
In How to Make Gold Glitter Comets I described the process of making relatively small,
single-shot gold-glitter comets. These were designed to be fired out of a star gun or a small mortar, with the
black powder lift charge preloaded into the bottom of the mortar, and a piece of Visco fuse inserted into the
bottom of the gun.
In this article I want to take that process one step further, and show how to make reloadable comets, similar
in construction to festival-ball and aerial fireworks shells. This construction technique allows the comets to
be easily and quickly loaded and fired, and reloaded as desired.
I'll show you how to construct 1.5-inch, 3-inch, and 4-inch comets. The smaller ones can be fired out of a
typical 1.75-inch festival-ball shell mortar PL3170. The 3-inchers can be fired
out of a 3-inch mortar PL3183, and the 4-inchers out of a 4-inch gun PL3184.
Warning: Fireworks devices such as comets and standard aerial shells are only safely fired out
of mortars constructed of paper, fiberglass, or HDPE plastic. Never fire these devices out of improvised and
unsafe mortars constructed of PVC pipe or materials other than those listed above.
The 3-inch comets actually measure 2.5 inches OD, and the 4-inch ones measure 3.5 inches OD. The 1.5-inch
comets do measure 1.5 inches OD, and are to be fired out of a mortar between 1.75 and 2 inches
There is perhaps no simpler a device than a comet, but a beautiful gold-glitter one never fails to catch the
crowd's attention and impress them. The smaller ones described here are perfect for that backyard,
consumer-type fireworks display, and the larger ones can fill the sky during any large, professional-type
There are also simple, fast-burning charcoal compositions, which can be used for this type of comet. They
leave a bushy, orange spark trail while ascending into the sky.
Gold Glitter Comet Composition
In this particular project, I'll be using the D1 Gold-Glitter composition that was
demonstrated in the article cited above. If you've been following along with the articles this year, the
procedure for mixing up a comp like this will sound very familiar.
To determine how much of this composition to mix up, I need to plan the comets that I am about to make.
Each size comet, if it is pressed with the hydraulic press, uses the following amount of the dampened
|Size of comet
||Amount of composition
|1.5-inch diameter, 1.5 inches long
|2.5-inch diameter, 2.5 inches long
|3.5-inch diameter, 3.5 inches long
Note: The 2.5 and 3.5-inch comets have to be pressed with a hydraulic press in order to
achieve dense consolidation of the composition. The 1.5-inch comets can be hand rammed using a pounding-post
and mallet, or they can be pressed hydraulically.
If they are hand rammed, though, only 2.25 ounces of composition will be able to be consolidated into a
1.5-inch long comet. Hand ramming simply will not achieve quite the density that a press can.
I plan on making four of the 1.5 inchers, and one each of the larger ones. So, I need to make 55 ounces of
the damp composition. I will be adding 5% (2.75 ounces) of water to the comp to dampen it, so I'll actually
end up with 57.75 ounces of the damp composition. This is 2.75 ounces more than I need for my planned comets,
so I think I'll simply press one extra of the 1.5 inchers rather than complicate the math involved. It never
hurts to have an extra comet.
In the small glitter comet article, I described starting with a black powder meal base. This time I'll start
with the individual raw chemicals, which works just about as well.
|D1 Gold Glitter formula
|| 55 ounce batch
|Aluminum, atomized, 325 mesh
I weigh each chemical out individually, and make sure each one, except the metal, will pass through the
100-mesh screen. If it won't, I'll grind it in the coffee grinder until it will all pass through the screen.
I never put metals through the fine screens.
A coffee grinder is used to mill individual chemicals only, and once it has been used for an oxidizer such as
the potassium nitrate, it is never used for a fuel such as the charcoal. A separate grinder is used for
The chemicals are all added to a plastic tub and shaken to mix them. Then the mix is passed three times through
a 20-mesh kitchen colander and mixed once again in the tub.
At this point, I weigh the mixed composition to make sure its weight comes up to the desired 55 ounces. This
step ensures that I weighed each component correctly, and that I didn't leave anything out. I can't tell you
how many mistakes, and the resulting poorly-performing devices, this step can avoid. In actuality the total
composition weight is typically a tenth ounce or so lighter than the total I was shooting for, due to some loss
to airborne dust from the lighter components like charcoal.
2.75 ounces of water is added to the mix and it is all shaken in the tub again. Then it is passed through the
colander again to completely integrate the water. One final shaking in the pail completes the preparation of
As I said, the 1.5-inch comets can be either hand-rammed or pressed in a small hydraulic press. I weigh out
either 2.25 ounces of the composition, for hand-ramming, or 2.75 ounces for pressing. The comp is poured into
the comet pump sleeve and the comet is either rammed or pressed.
Hand-Ramming, and Hydraulic Pressing, 1.5-Inch Glitter Comets
The same is done for the 2.5-inch and 3.5-inch comets; comets of these sizes must be pressed
Pressing 2.5-Inch and 3.5-Inch Glitter Comets
When using the press, I apply about 5000 pounds of force on the1.5-inch comet pump, which amounts to about
3000 psi on the composition.
With the larger pumps, I'll apply about 10,000 pounds of force, which applies about 2000 psi on the comp in
the 2.5-inch pump, and about 1000 psi on the comp in the 3.5-inch one. This is enough pressure if I allow
the press to "dwell" for a minute or two on the pump, slowly compressing the comet, while I regularly pump
the pressure back up.
One of the things I really love about this glitter composition is that once it has been pressed, it forms a
rock-solid comet. This also makes the comets a bit difficult to extract from the pumps once they have been
pressed (no problem extracting a hand-rammed comet, though). A comet extraction-sleeve can make this final
process much easier. The sleeve is simply a hollow cylinder that the pump sits in the top of, and into which
the comet is pushed with the press.
Using an Extraction-Sleeve to Push a Comet Out of the Pump
1.5-Inch, 2.5-Inch, and 3.5-Inch Gold Glitter Comets
Drying the Comets
Since these comets only contain 5% water, they come out of the pump relatively dry, and pieces of them can
actually be lit and tossed even before they are dried.
But, because they contain potassium nitrate, fine aluminum, and sodium bicarbonate, there can be unwanted
chemical reactions if they are allowed to get too hot before they dry a bit. So, I air dry them in the shade for
a few days before they are put into the drying chamber for a few more days
to complete the drying process.
You can notice on the tops of the two large comets in the photo above that I've written their weights with a
Sharpie marker. I did this immediately after pressing them, and then once a day as they dry. Once their weight
equals 0.95 of the original weight, I know all the water is gone and they are completely dry.
Priming the Comets
You can also see in the above photo that the 1.5-inch comets have been primed, per the instructions in "How to Make Gold Glitter Comets". I do prime both ends of these comets, rather than only one end, which I did in the original article
because the comets could be used as rising tails on shells. Priming both ends ensures that the flame propagates
quickly to the whole comet's surface when it is ignited.
Finishing the Comets
In "Making Mines", I illustrated a simple "piston" which is used to propel all the mine-stars
out of the mortar at one time, and straight up into the sky.
I'll use a similar piston under each of these comets.
"Why", you might ask.
Often, when you see a large comet shot out of a mortar, you'll see some small, lit fragments come out of the
mouth of the gun with the main comet, or else you might see the whole comet split into two or three pieces,
ruining its effect.
I envision these defects to be the result of the impact of the initial blast from the black powder lift hitting
the bottom of the comet, possibly chipping the bottom edges off of it, combined with the comet twisting as it is
propelled up the mortar. In that case, the comet is wedged in the mortar, and suffers damage due to those stresses.
All of this, of course, occurs in a matter of milliseconds.
To prevent such damage, and to get the comet out of the gun in one piece, I employ the piston. This is made out of
two cardboard discs, with a hole in the center of each, and a length of cardboard tube glued between them. The
discs and tube are the same OD as the comet, and the tube is about that same distance long.
None of these dimensions is extremely critical, though. While I like to have the discs the same diameter as the
comet, the tube can be a bit smaller or larger, and the tube can be a bit shorter than the comet's OD. This ain't
rocket science. It's comet science!
Unlike the pistons I showed in the article on making mines, with these comet pistons I only put one hole in the
center of each disc to allow fire to get to the comet easily. I also only use the one, large tube, instead of the
two tubes used in the mine pistons.
Cardboard Pistons Sized to Be Used Under Each Size Comet
I prepare black powder lift bags, and insert quickmatch leaders, once again as described in the mines article.
The amount of lift for each comet size is as follows:
||0.3 ounce of FFg or FFFg sporting black powder
||0.75 ounce 2FA black powder
||1.5 ounces 2FA black powder
Black Powder Lift Charge, Baggie, and Quickmatch Fuse Leader
For the quickmatch fuse leader, commercial quickmatch, homemade quickmatch, or fast-fuse wrapped with aluminum foil duct tape
may be used.
The lift charge and leader, the piston, and the comet are then wrapped up in two turns of kraft paper, which
is glued to itself. The ends of this wrapper are then tied closed with clove hitches, and the excess paper is
trimmed from the bottom. The size of paper for each size comet is:
Kraft Paper Wrapping the Comet, Piston, and Lift Charge
Visco fuse is installed into the quickmatch leader and taped in place. The leader is then S-folded and tied to
keep it neat until the comet is loaded into a mortar.
Finished 1.5-Inch Gold Glitter Comet
(Click Image to Play Video
1.5-Inch Gold Glitter Comet Ascending
You Must Have Java Turned On To View This Video
The second comet in the video is made with a slightly different formula I came up with by modifying and combining
a couple of other formulae. It burns a bit more slowly (yes, the comet did burn out before it hit the ground) and
the tail is a longer, slightly more delayed glitter, which sparks like a Senko Hanabi sparkler. I've labeled this glitter
You can see that one of the advantages of this formula is that with a longer burn time, comets made with it can be
pumped about 2/3 as long as their diameter (The comet in the video was 1.5 inches long, which I'd shorten to 1
inch next time). So, it's a bit more economical to make and use.
|N1 Gold Glitter formula
|| 55 ounce batch
|Aluminum, atomized, 325 mesh
Try both formulas and see what you think. I will say that when one of the two-pound, 4-inch D1 babies is fired,
it's hard to take your eyes off of it. Very impressive, indeed!
So, you have your homework. Two formulas to play with, and three different sizes to make.
Have fun and stay green,
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