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Skylighter Fireworks Tips October 2nd, 2008 -- Issue #114 IN THIS ISSUE: Making Fireworks Mines Free 4-Inch Fiberglass Mortar Tubes Visit Skylighter's Project Plans

You know, right around the time I first started making fireworks, I was fortunate enough to come by a big stash of various colored stars right before July 4th. Big ones, little ones, color-changing, etc. The Mighty Fourth was looming large and I wanted to include at least something of my own manufacture in my yearly display.

I did not have everything I needed in order to make shells, nor did I have the knowledge and confidence to take on shell-making as my first project. What to do? I had all these stars, and plenty of black powder. I had a big field out front, with cooperative cows in it, and plenty of distance. But the clock was ticking, and I only had about 3 hours available to make whatever it was gonna be. Time was a wastin'!

Ah, HAH! I know what: Mines!

I can make mines, and make 'em fast.

So, mines was it (mines were it?-still sounds wrong). I hopped to it. I set up my manufacturing facility, actually our battle and pyro-scarred picnic table, out in the field in back of my house. I created a little assembly line, and for the first and only time, recruited my then-wife to assist.

Two hours later, we had us about 20 finished 3-inch mines using methods that can politely be described as more primitive than those Nedski provides you in today's newsletter.

Everything was to be hand lit, and with my little audience set up properly with recliner chairs and coolers, I went to it with my trusty Bernzomatic torch. All went well. The oohs and ahhs reached me even over the crescendo of mortars firing and crackling dragon eggs overhead. They were impressed and happy, and I was happy they were happy until...

...Until one of the 3-inch mortars blew up right after I turned away from it. And that mortar took out two mortars on either side of it. All were mines. And all went up at once. I was in cotton blue jeans and a long-sleeved cotton shirt, so the few stars that came my way just bounced off doing no damage at all other than singeing my shirt.

But one whole mortar rack was wiped out. Startled me to say the least.

Why'd it happen? In a nutshell, because I did not make the mines the way Ned shows you below. What I had done was to overload at least one of the mortars. There was so much pyrotechnic material--black powder and stars--in that gun, that it created a kind of compression when it ignited. Not unlike what would have happened if I had plugged the top of the mortar. Take it from me, there is a clear limit to how much stuff you can safely load into a mortar.

None of this is meant to scare you. Rather I just want to point out that haste can make more havoc than waste. Do it right. Follow the excellent, proven instructions given to you by experts like Ned Gorski, and you will be a lot more likely to survive your own projects.

To make Ned's mine project a little less painful to your pocketbook, you can get industrial strength mortar tubes free in the special offer below if you order before Thursday, October 9th.

MAKING FIREWORKS MINES

Whether you are new to fireworking or a seasoned veteran it always pays to regularly study good pyro-safety guidelines and to notice whether or not your work habits are conforming to those recommendations.

Please refer to these links:

Fireworks Safety 101 by Kyle Kepley, intro by Ned Gorski

Fireworks Safety Manual, a collection of essays by Bill Ofca


There is a beautiful photo on the cover of Dr. Takeo Shimizu's Fireworks, The Art, Science and Technique (FAST). At the top of the picture is a huge, double-petaled, fireworks-shell starburst, with several smaller star-flowers between it and the ground. And, at the very bottom of the shot is a spray of stars shooting upward from the ground where the shells were fired: a mine.


Similarly, the back cover of Hardt's Pyrotechnics shows a rainbow of 5 colored mine-shots, with corresponding colors of small and large starbursts over each one.


Fireworks mines, or star-mines, can be used in conjunction with aerial shells to create such an effect, filling in the low sky as the starbursts fill the middle and high sky.

These devices are also very effective during a display when they are fired as a mine-run: a series of mines fired in sequence from various spots on the field in harmony with beats of music in the soundtrack.

A single mine, a mine-run, or a wall of simultaneously fired mines all serve to bring the audience's attention back down to the ground, providing contrast and variety during a fireworks display.

For precise timing of electrically fired mines, putting the electric match right down in the lift powder eliminates the objectionably noticeable, split-second delay, which occurs when a length of quickmatch leader is ignited by the electric match.

If I am going to put the e-match into the lift powder, I still attach a couple of inches of quickmatch to the electric match, with the e-match's protective shroud in place. This ensures that quite a bit of flame will be introduced into the lift powder, and it further protects the e-match from premature ignition due to shock or friction.

One of the clubs I belong to, The Bluegrass Pyrotechnics Guild, has assembled and fired literally thousands of 4-inch mines over the years for our displays at the PGI annual conventions. These devices can be very easily constructed, and they provide a nice hand-made touch to a fireworks show.

In this article I'll detail two methods of constructing 4-inch mines. But, these methods can be applied to any size mine, from 1-3/4-inch through 6-inch models. Simply by varying the size of the stars, the materials used in the assembly, the amount of lift powder, and the size of the mortar from which they are fired, mines can be tailored in size to any effect and any venue.

Making the Stars

Each 4-inch mine will use about one pound of stars. I like to use 1/2-inch stars in 4-inch shells and mines, and in mines, I prefer a fast-burning star, which burns out before it reaches apogee and begins to fall back to the ground.

For this project I'll use two variations of one type of star, commonly known as Gold Spider Web (Ofca's Volume 5, Mastering Cut Stars the Easy Way) or Chrysanthemum 6 (Shimizu's FAST). This is a very fast-burning charcoal streamer star which is easy to make, and which produces bright streaks of sparks in the sky.

So the final working formula was:

Chrysanthemum 6	Ratio	16-ounce batch
Potassium nitrate	0.55	8.8 ounces
Charcoal, airfloat	0.33	5.3 ounces
Sulfur	0.07	1.1 ounces
Dextrin	0.05	0.8 ounces

The individual chemicals are screened through a 100-mesh screen, and any that will not pass the screen are milled in a coffee grinder until they will pass. (I have a grinder that I only use on oxidizers like the potassium nitrate, and one for fuels such as charcoal. Except for when I am ball-milling black powder, I never mill complete compositions, only individual chemicals.)

After I screen them individually, I mix them through the 100-mesh screen, and then shake them in a closed plastic tub. 1.3 ounces of water is added (+8%) to the composition, and it is thoroughly shaken in the closed tub once again. The dampened composition is then pushed through a 20-mesh kitchen colander to completely incorporate the moisture into the composition.

I use my 1/2-inch star plate to press 1/2-inch diameter by 1/2-inch long stars, as detailed in Fireworks Tips #92, which I dry overnight in the drying chamber.

The stars are then primed, as shown in Fireworks Tips #93, and dried overnight again.

I make two, 16-ounce batches like this, and one 16-ounce batch of the same composition with 3.2 ounces (+20%) of 10-185 mesh spherical titanium (CH3001) added to the composition after all the 100-mesh screening is done. I never put any metals through my fine screens. The addition of this titanium will produce bright silver-white sparks as the stars burn, creating a silver-streamer star.

So, with these three, one-pound batches of stars, I can now proceed to make three, 4-inch mines.

Mine Assembly

There are some extremely simple ways to assemble mines. "Bag Mines" can be as simple as a paper bag with some lift powder in a baggie on the end of a fuse-leader inserted into the bottom of it. Then some stars are poured in, the neck of the bag is tied closed and she's ready to fire.

In Introductory Practical Pyrotechnics, Tom Perigrin shows how to make a simple mine by installing a baggie of lift on a quickmatch leader, sliging that into a cardboard-tube mortar. Then dropping in some stars, bundled in some tissue paper, into the tube.

These simple mines are functional, but they'll typically not fire all the stars out the top of the mortar together and in a straight column of fire. Because there are some stars to the sides of the lift powder, they get fired a bit sideways and bounce around a bit in the mortar before they exit. Some of these stars can "ploof" out of the gun and drop onto the ground.

So, I like the following slight variations on the simple-mine theme. They are more effective at getting all the stars lit and out of the gun in a straight-up spray of stars.

Typically, mines use the same amount of lift black powder, and the same amount of stars, as a cylindrical star shell of the same diameter. I like to refer to the charts on Pages 138-140 of The Best of AFN II to determine these amounts.

For a single-break, 4-inch cylindrical shell, 1.5 - 2 ounces of commercial 2FA black powder is recommended for the lift powder. I'll use 1.75 ounces in these mines.

I have made three 24-inch lengths of homemade quickmatch for the mine leaders. Similar lengths of commercial quickmatch (GN3001), or super-fast paper fuse (GN1205) (wrapped in aluminum foil duct tape), can also be used as mine leaders.


I then weigh out the three 1.75-ounce loads of 2FA lift powder, and put them in individual plastic baggies. The one-inch of black match protruding from the quickmatch leaders is folded back on itself, and then inserted into a baggie of lift. Masking tape is used to seal the baggie around the leader, and the extra plastic trimmed off with scissors. Then a final wrap of masking tape seals the baggie/tape to the quickmatch.

Method #1 - The High Quality Method

If I'm only going to make a few mines, and I want them to be top-quality, I build them this way.

First I make a "piston" to go between the stars and the black powder lift charge. Here's a photo-essay of that process. It uses two 4-inch kraft discs (DK3401 or DK3500), a 2-inch length of 3/4-inch ID tube (TU2053 or TU1065 or TU1068), and a 2-inch length of 3-3/8-inch or 3-1/2-inch OD tube (TU2300).

Places like HarborFreight.com sell the sets of hollow gasket punches for ridiculously low prices. I much prefer to make the holes in discs with the punches instead of with a drill.

This piston will allow the lift-gasses to pass through it, igniting the stars, and will evenly push the stars out of the mortar and into the air in a tight column.


The center holes in the discs are 1/2-inch diameter and are large enough to allow the quickmatch leader to be threaded through them. The other holes are 3/8-inch diameter, keeping these holes smaller than the size of the stars that I am using.


Now, I position the piston on an 18x24-inch piece of kraft paper as shown. The paper is rolled up around the piston and glued to itself with hot-glue. Then the end with the baggie of lift powder is gathered together, tied with string in a clove-hitch knot, and trimmed with scissors. This is my mine casing.

Kraft paper is available from stores like Staples or Costco (white butcher paper), on-line from places like ULine.com, or paper grocery bags can be used.


Now, it's a simple matter of dumping the pound of stars into the open end of the mine casing, gathering the kraft paper around the leader, and tying it securely in place.

When filling a mine like this, I like to keep the depth of the stars equal to the diameter of the mine. So 3-4 inches of stars in this mine is my goal.


A piece of Visco fuse is inserted and secured into the end of the leader, which is then S-folded. A safety cap can be installed over the fuse, and a band of masking tape sticky-side-out, followed by a band of tape sticky-side-in, secures the bundle until the mine is to be loaded into a mortar.


Here are shots of the two mines made this way. They had different types of charcoal in the stars, commercial airfloat and homemade poplar airfloat, but I didn't see any significant difference between the two.


As you can see, the piston pushed all the stars out evenly, and very high. Nice, bright, fast and dramatic mines.

Method #2 - The Quick Method

The above "high-quality" method produces very nice, traditional mines, but it is a bit time-consuming. When the Bluegrass guild wants to construct several hundred mines in an afternoon, we've developed the following system. It is quick and easy, and while it does not allow the use of quite as many stars, and the quality of the mine-display is not quite as nice, it is a very effective method for producing large quantities of mines quickly.

We start with the same lift-bag/leader configuration as shown above.

Two disposable plastic drinking cups are used for each mine. For these 4-inch mines, cups that are 3-5/8-inches in diameter at the top are ideal.

One of the cups has its bottom perforated with a hot, pencil-tip soldering iron. I've tried using a drill for this operation, but often the cup-bottom will crack when doing so.


The mine leader is inserted through the center hole in the cup. That whole assembly is placed into the second, intact cup, and the perforated cup is filled with stars. In this case, it held 12 ounces of the stars.


Then the assembled mine is sealed with four, 9-inch strips of aluminum-foil duct-tape. The leader is completed with Visco fuse and S-folding as shown with the paper-cased mine in the Method #1 above.


This mine was made with the silver-streamer stars, which contained spherical titanium. While it did not contain the same quantity of stars as the previous two mines, and it did not fire quite as high as they did, it was still a very nice, bright mine.

Conclusion

Here is a link to a video of the three mines in action. They were all impressive, firing 30-40 feet into the air, and producing unique effects.

While these are simple devices, they can be crafted with care, and will add variety to a fireworks display.

Have fun with them, and remember, "A mine is a terrible thing to waste."

(I hope that line at least elicited a groan or two, if not a chuckle. My wife, Molly, only gave me that blank "wife's" stare, and that curled-up lip, when I said it to her.)

Until next time, Enjoy!
Ned

ngorski@skylighter.com



Mines are one of those effects that are difficult to find in Class C fireworks by themselves. They often come packaged in a cake with a lot of extra effects you don't want. Ned's Fireworks Mines project can use any kind or color of stars that you want, even flying fish fuse. So you can make exactly the effect you're looking for. They're easy to make and are a great way to test stars or get rid of extras from a batch. So, if you buy $110 worth of anything from Skylighter between now and Thursday, October 9th, you can get:



Two free 4-Inch Fiberglass Mortar tubes, worth $41.60.

And if you place your order before midnight Monday, October 6th we'll toss in an early bird bonus of 2 pounds of 80-325 mesh aluminum, worth $32.94. This is Skylighter's Atomized Aluminum, 80-325 mesh, #CH0120. Just use it in Ned's willow diadem formula in place of the titanium. You'll have all the stars you need for your 4-inch mines.

So, if you order $110 worth of anything from Skylighter by midnight Monday, October 6th you will also get more than $74 worth of freebies, and be well on your way to making Ned's 4-Inch Mines.

To get your 2 free 4-inch mortar tubes and early-bird bonus click here.

Note: You must enter the promo code during checkout. You will not see the free mortar tubes in your shopping cart. If you take advantage of the early bird special, you will not see the free aluminum in your shopping cart either. We will add your freebies once we receive your order. Also, shipping costs will be higher than what you see in your shopping cart, because the weight of the freebies will not have been calculated there.