May 2018: This isn't really relevant anymore. As I got older my interests changed and I don't feel as strongly about this subject anymore. But I'll leave it up since it's still great fun on July 4.

Might as well come into the open with this. I like fireworks, as possibly many males do, even adult ones. Other people's ideas of adulthood, i.e. that once you get older you should devote your time solely to drinking, gaming, reading works of literature, exercising, or any other notion of adulthood made up on an individualized basis, should not force you to repress the desire to watch things fly up and go boom. This might be related to the odd realization I've come to, that things that fly or otherwise leave the surface of the earth really interest me. Things like model helicopters, drones, kites, rockets, space, and fireworks that go really high. Kerbal Space Program is something I've not allowed myself to ever get into, as it would be too much. Ditto for Orbital, although there was a time when I was heavily into Flightgear Flight Simulator.

As such, I'm going to place a bit of information here about fireworks fun. Originally there was supposed to be more, but then I realized that this isn't exactly anonymous. So there will be more fireworks reviews and tips instead.

Disclaimer: I am not responsible for any of the decisions you might make with this information.


 

Rockets

These days and unlike in the UK or Europe, it seems that the primary (and cheapest) way to put fireworks effects into the sky is via a mortar, or tube. Additionally, the outlawing of bottle rockets, which are made for shooting out of a bottle, has really dampened the use of rockets in fireworks outside of the hobbyist world. Nevertheless, fun can still be had with some commercially-manufactured rockets.

Alternatively, you can make sugar rockets and attach effects to them. In the past I've hot-glued Piccolo Petes, very small fountains, or a couple of firecrackers to my sugar rockets, then fused them so that the additional item ignites first (except with firecrackers), and then the rocket.

Commercial and hobbyist skyrockets are made with compressed black powder, in different formulations depending on the need for speed and which type of rocket is wanted. The compression can take place using ramming tools and a mallet or via an arbor press (this one's more efficient but more expensive, and takes up more space). The core can extend all the way through the fuel, creating what is called a core-burner, or only a bit into the fuel, creating an end-burner. The former burns faster, the latter burns slower but has a smaller nozzle. Most of my early sugar rockets were nozzle-less core-burners, which meant low thrust but fast burn.

There are plenty of videos and tutorials available online for BP rockets, including those by Ned Gorski and on Skylighter. In my opinion the best hobbyist skyrockets are those made by TR (plenty available on Youtube), which are each works of art that take upwards of 20 hours each. 

Commercial skyrocket fireworks look about the same, except that the tube is usually plastic, and the nozzle is just a hole in one end of the tube. Instead of the passfire setup, some quick-burning fuse leads into the heading. When the rocket burns through, the black powder will ignite the fuse. This makes for the delay you can see and hear in this Winda firework.

Commercial skyrockets are often filled with empty space, which can be removed to make them go higher. (Note: tampering with fireworks like this may be a crime in your area, so please check the local laws before doing this.)

Let's take these rockets, going from right to left.

The Orange cone at the bottom actually hides the fuse and gets removed when you need to light the rocket anyway.

The black cylinder is fine, as that is the BP rocket, but if you are really intense take off the paper around it.

The wide cylinder is just a cardboard tube, inside which there is a smaller cylinder which contains the heading. The smaller cylinder often bounces around inside the larger tube, leading to failures. You can remove the larger tube, then hot-glue the heading carefully to the BP tube. Typically there will be some fuse trailing into the heading, so make sure that the black powder of the thrust fuel touches the fuse.

The cone at the top can also be removed. I think that at this size and speed, keeping it gives a negligible reduction in air friction.

Two black powder thrust tubes can be combined, one on top of the other, but the result will only go 1.5 times as high, due to weight issues. Additionally, quick ignition of the second stage must be ensured or else the rocket could tilt in a dangerous direction.

Cremoras

Warning: The legality of this is highly questionable. In fact, purchasing black powder for this purpose may be illegal.

Cremoras create a fireball effect, by lofting into the air some quantity of light material and igniting it, which is similar to how a thermobaric bomb works. Originally the effect was created using a brand of coffee creamer called Cremora, but since that stuff is hard to find these days, various other powders are used. Skylighter has the best tutorial.

Please note that the effect is very hot, especially if charcoal is used. The heat of a fireball from a 28 ounce can filled with airfloat charcoal can be felt 20 feet away, as if you momentarily stuck your face a foot away from a bonfire. Videos do not do this effect justice, especially when a mortar tube (as for artillery shells) is used. 

Flash

Injuries from Fireworks (Warning: Gory and NSFL)

The above is why I won't put anything here. From A Safety Manual for Experimental & Amateur Rocket Scientists (Download), which I reread several times a year:

"A typical flash powder formulation has a critical detonable mass of between 30 and 50 g (1 and 2 oz). This means that such a quantity will detonate with concussion and a shock wave when ignited in open air (unconfined, just loose in the open). A cup or a shell casing confines the flash powder enough to accelerate the reaction. (Less flash than the critical mass will just burn extremely rapidly and violently.) Compare this with black powder, which has a critical mass of over 200 kg (500 lbs).

The average 3-in salute containing about 100 g (4 oz) of flash powder will dismember a person, not just blow off a hand. As the size of the charge doubles, the force of the explosion increases eight times. When a pound of loose flash goes off in a wooden structure the flash, fireball, and chest-pounding report is an awesome experience. Generally, nothing larger than fist-size is left of the shed."

Leave the flash to the professionals and don't mess with it unless you have the appropriate tools, mindset, and age.