Spin Stabilized Rockets
Once you start building your own fireworks, there will be lots of times when you're waiting for a project or component to dry, waiting for your next shipment of chemicals, or just simply want some instant pyro gratification. Enter the spin rocket, aka stinger missile. These little guys take just a few minutes to build, require minimal supplies, and yet still give you that fire and smoke fix you're looking for. This picture is the tooling kit available at Skylighter.
To start, a 3 inch piece of 1lb. rocket tube (¾ inch ID, 1½ inch OD) is placed on the spindle base. I rammed a plug of 5g of bentonite clay, just until the tube shows a slight bulge. Once the plug is formed, you need to mark the top of it on the tube. This is where the side vent hole will be drilled, which is what will cause the rocket to spin when lit. Using the jig and drill bit from the kit, a tangential hole is drilled as the picture shows.
The tape you see on the bit shows when it has gone through the wall so the opposite wall is not weakened. Now, as Dan Williams recommends, I treated this vent hole with a little sodium silicate to heat proof it. I think it's worth this small extra step. Next, the tube is placed back on the spindle and the fuel is rammed. I used 16g of meal powder mixed with .6g spherical titanium (for a nice spark effect) and rammed it in 5 increments. It must be rammed firm. Be sure to keep the vent hole covered when you're ramming or the powder will blow out all over making quite a mess.
The top piece of tape in the picture is to mark the location of the clay plug, the lower one to mark when I'd reached the top of the spindle so I could switch to the solid rammer.
The next picture shows where the fuel should be in relation to the end of the tube once you've rammed it all, about ¾ inch from the top. If there's much less space than that, you haven't rammed hard enough and you run the risk of the rocket blowing up. Once you reach this point, you need some delay composition to allow the rocket to reach maximum height. You can use most any BP compatible star mix, dampened very slightly and pressed in with hand pressure only. I use 3-4g to bring the level to about 3/8 inch from the top.
Now you can decide on a header. I didn't have much luck with star payloads, as they seemed to make the rocket too heavy. I found it more satisfying to watch the trail of sparks reach maximum altitude. I filled the remaining end of the casing with standard 70/30 flash powder. You will definitely want to make sure your delay
composition weights aren't too heavy so the rocket doesn't return before exploding. Keep a notebook and when you find the exact amount of a particular composition, record it for the future. Next, you just need to seal the top and re-open the side vent hole with a 1/8 inch drill bit, turned by hand. I used a bit of meal powder mixed with nitrocellulose lacquer on the end of my fuse to secure it inside the core.
The last picture shows the finished rocket on the launch stand. You need a nail long enough to support the rocket in the core so it can spin. You should also file the tip of the nail down so it doesn't press into the core. I threw this stand together from a couple of scraps of wood I had. You can see the S-shaped burns from the side vent. I never got around to building a more sturdy launch pad from aluminum. Once lit, these rockets should easily fly 80-100 feet high.