Roman candles are impressive to watch. They are relatively difficult to make, compared to the other types of homemade fireworks, but they are well worth the trouble.
1) Buy a 1/2 inch thick model rocket body tube, and reinforce it with several layers of paper and/or masking tape. This must be done to prevent the tube from exploding. Cut the tube into about 10 inch lengths.
2) Put the tube on a sheet of wax paper, and seal one end with epoxy and the drying agent. About 1/2 of an inch is sufficient.
3) Put a hole in the tube just above the bottom layer of epoxy, and insert a desired length of water proof fuse. Make sure that the fuse fits tightly.
4) Pour about 1 inch of pyrodex or gunpowder down the open end of the tube.
5) Make a ball by powdering about two 6 inch sparklers of the desired color. Mix this powder with a small amount of flash powder and a small amount of pyrodex, to have a final ratio (by volume) of 60% sparkler material / 20% flash powder / 20% pyrodex. After mixing the powders well, add water, one drop at a time, and mixing continuously, until a damp paste is formed.
This paste should be moldable by hand, and should retain its shape when left alone. Make a ball out of the paste that just fits into the tube. Allow the ball to dry.
6) When it is dry, drop the ball down the tube. It should slide down fairly easily. Put a small wad of tissue paper in the tube, and pack it gently against the ball with a pencil.
7) When ready to use, put the candle in a hole in the ground, pointed in a safe direction, light the fuse, and run. If the device works, a colored fireball should shoot out of the tube to a height of about 30 feet. This height can be increased by adding a slightly larger powder charge in step 4, or by using a slightly longer tube.
8) If the ball does not ignite, add slightly more pyrodex in step 5.
9) The balls made for roman candles also function very well in rockets, producing an effect of falling colored fireballs.
WARNING: Take necessary precautions when doing this homemade roman candle. The author will not be liable for any damages or injuries this may incur. Do this at your own risk.