Siegmund Posted June 23, 2020 Posted June 23, 2020 Seems there is rather little written about these, aside from the 3 pages in Lancaster, and people posting pics of the ones they have made without saying much about how they made them. Lots of the comps consist of nothing but ~50% KP and ~50% metal. And Lancaster says "...successive increments of composition are lightly tapped down with a mallet and drift." That....makes me feel like I am missing a piece of the puzzle. Don't we have to do something to these mixtures to desensitize them before we start tapping with a mallet? We are past due for a good tutorial on waterfalls - not just how to make them safely, but a handy table of how far the sparks will far before burning out as a function of flake size, tube diameter, and comp used would be lovely too. (Once the making-them-safely part is out of the way, I'd contribute to the making of the latter list... have an idea for something I need to build for my parents' 50th anniversary in September, and know I am going to need some trial and error to dial it in.)
Mumbles Posted June 23, 2020 Posted June 23, 2020 The step that may be missing is that waterfall compositions are usually loaded damp into thin paper tubes. The composition is wet until it just begins to clump, think pressed star consistency. A thin paper tube both burns away with the composition and allows moisture to evaporate throughout the entire tube. Additionally, while that composition is technically correct it glosses over the fact that a mixture of aluminums is used. Something typical might be along the lines of this: Bright flake Al - 70%Medium flake Al - 15%Coarse flake Al - 15% This is just a prototypical example. Other things like titanium, atomized aluminum, MgAl, coarse charcoal, etc. can all be included. When you have a good portion of coarse metals in there, the sensitivity goes down. Take that with a grain of salt, as things like titanium could add increased friction or abrasive properties as well. Coarser the metal, the longer the fall. Start at 10ft at least, if not 20. You probably wont need to use a mallet. You're going to need a support sleeve for these to make them without bursting the thin casing. I don't recall off the top of my head, but there is a standard sized combination of wooden dowel and PVC/CPVC/Copper pipe that works great for this. Figure it out at the store and let us know if you figure it out. I think it's 5/8" dowel and one of the plastics off the top of my head. You can almost certainly compress the composition enough using just hand tamping the composition. One other suggestion. Red gum is often added to silver streamer stars to increase the tail length. It basically acts as the primary combustion fuel in the base of the star and leaves more aluminum to fall out and burn in the atmosphere. I bet the same thing would work with waterfalls. I'm sure it's already been done and out in the knowledge base, but I thought it was worth bringing up.
davidh Posted June 23, 2020 Posted June 23, 2020 They are definitely loaded damp, usually with red gum / alcohol.
Siegmund Posted June 23, 2020 Author Posted June 23, 2020 (edited) I am not surprised they are loaded damp - but I wasn't seeing anything that said what to dampen them with (and whether the point of the moisture was to desensitize, or to transport a binder, or to dissolve a tiny bit of the oxidizer to make it hold together.) An abundance of red gum and alcohol on hand so that shouldn't be a problem. Given that dowels and piping come in every 1/8" size up to an inch, I imagine any pair that are 1/8" apart would do nicely. Will be post-Fourth that I give it a try (coarse aluminum flakes are waiting for my next order of chems) but will update the group when I do. Edited June 23, 2020 by Siegmund
Recommended Posts