Basic Whistle Rocket Tools
WARNING AND DISCLAIMER: If you are underage, then consult with your parents or guardians before attempting any of this. You are on your own - I'm not responsible for your actions or harm you may bring to others because of your actions. Making the items described below can result in injury or death to you or people in your vicinity. Some things mentioned here may be illegal to make in your city, county, state, or country so check the laws that apply to you before you attempt anything described here. These notes are not complete on purpose. If you are reading them and new to pyrotechnics, then you are making a mistake. Stop now - this page is not for you. Get a beginning book on fireworks (see Skylighter or American Fireworks News (very quick shipping) for a start) and read up. You can't make any of this work without more information so read up or join a club or ask someone to help you.
Generic Tooling for Whistles
Only press whistles! See presses.html for information about presses.
Above is a general guide for creating whistle rocket tooling from aluminum stock. You can vary these measurements depending on your particular need. Indeed, a very wide range of spindles will work and you just have to select one and design your whistle mix around it. If you are just starting out, then use the above as a first guide. It will be the easier to have a successful flight if you start with known good match. You can use 76/23/1 + 3 mix with the above with no problem. (76 parts potassium perchlorate, 23 parts fuel (sodium salicylate or benzoate), 1 part iron oxide, and 3 parts mineral oil.) See Whistle Tests for a more complete summary of making whistle mix.
A. Spindle that is 1.86 diameters long (approximately). The diameter at the throat (where the 30 degree taper starts) should be more than .55 the width of the tube. The tubes for whistles are usually about half as long as for BP. Remember that if you order a custom tube reinforcement.
B. Base. Keep it small enough that you can put it in a vice
C. First ram. The center hole does not have to go completely through (and probably shouldn't). Ram is usually marked to indicate if it is too close to the bottom of the tube (thus ruining the spindle). The length is the length of the tube plus 2".
D. Second ram. Ram is usually marked to prevent jamming on spindle. It is 2/3 length of the first ram.
E. Cheater bar to free stuck rams. When pressing, the material will sometimes ooze around the ram and stick it. The cheater bar helps to free the ram. The usual solution to sticking rams is to use smaller increments of composition.
A set of tools with sleeve for 1 1/8" tubes. You can learn more about sleeves at extras.html. The above tools are made to the 'generic' specification seen in the diagram just above this. For safety's sake, use a blast shield when pressing with this tooling!
While we don't get deeply into whistle on this website, the above is a general diagram for making whistle rocket tooling. It is not aggressive - you should be able to make these dimensions work with most whistle formulas. Do not make whistles until you've had some experience under your belt. NEVER RAM WHISTLE. Whistle is much more sensitive and powerful than BP. Always use shielding when pressing whistle rockets.
One Pound (and bigger) Whistle Alternatives
For one pound whistles (3/4" I.D.), I like to use 76/23/1 whistle mix with +3% mineral oil. For the core, I use a 1/4" stainless shaft that is 2.25" long and slightly tapered and then polished. It can be made from a stainless steel bolt and a sander. Chuck the bolt in a drill and then run it on the sander while the sander is also running. Get the angle you want and then polish with fine emery cloth. Use the threads from the bolt to secure the core to a base. If the tool gets stuck in the rocket after pressing, you can unscrew the base and use a washer and nut to extract the core.
Using this method, a one pound whistle rocket will lift a one pound header to several hundred feet. I put in a 3-5 second delay when firing heavy loads with these. Generally, hot whistle burns at about 4 seconds per inch. I put a one inch delay over the core and then cap the grain with a clay bulkhead to stop blowouts.
This same technique can be used for a 4lb whistle and even 6lb whistle. Use a 5/16" stainless steel bolt and 2.25 to 2.5 inch length. Above is a picture of a 4lb (1.25 inch) spindle.
Click on the above picture and see a movie of a 6lb whistle with just a 1.5 inch spindle - made the same way as the 4 pounder..