Pyroitaly Posted August 9, 2022 Share Posted August 9, 2022 (edited) Hi pyros, I have a question about this star composition below..what is the burn rate of these stars? I think they burn super fast. 43. KClO419. Ba(no3)212. Gum Accaroide22. Al negro 2um4. Dextrin1. Boric Acid Edited August 10, 2022 by Pyroitaly Link to comment Share on other sites More sharing options...
Arthur Posted August 10, 2022 Share Posted August 10, 2022 As no two people will have exactly the same mesh size and mesh cut mixture of each ingredient no two people will get exactly the same burn rate. You will need to do tests if burn rate is critical. Link to comment Share on other sites More sharing options...
SharkWhisperer Posted August 10, 2022 Share Posted August 10, 2022 He's using a comp with 62% traditional oxidizers. And 60% of the fuel is hot-ass 2-um flash Al. Yes, it can be expected to burn fast. If you want it to burn slower then try: 1) reducing oxidizer; 2) increasing fuel; or 3) changing metal from 2-um reactive Al to 5-um atomized or similar (I'd try this first). If pyro flash-grade Al is your primary fuel, expect a "fast" combustion rate. Why are you using both red gum and dextrin (both binders, different fuel qualities) in the same comp? If no reason, dump one. They are minor fuels and one or the other could be a binder (not specified) compared to your Al, so adjust accordingly. Jopetes is respected in the community, but no comp is ever perfect. And like Arthur noted above, chems can differ (hopefully not hugely) but most any formulation based on flash-quality Al will likely burn fast if provided sufficient oxygen. Link to comment Share on other sites More sharing options...
cmjlab Posted August 11, 2022 Share Posted August 11, 2022 (edited) The red gum may be to "over fuel" the flash components, much similar to photoflash, leading to the brilliance without the bang. I believe that if you took a photoflash formula and reduced the fuel, you would end up with a closer to stoichiometric flash formula that's loud like a typical flash.Just a thought, I've not made photoflash or the OPs star formula.Charles Edited August 11, 2022 by cmjlab Link to comment Share on other sites More sharing options...
cmjlab Posted August 11, 2022 Share Posted August 11, 2022 (edited) Well shit. After re-reading your post shark, I believe I said what the first half of your response says!Just didn't want him to remove the red gum, but not reduce the oxidizer to account for it, and end up with a loud flash formula!Charles Edited August 11, 2022 by cmjlab Link to comment Share on other sites More sharing options...
Pyroitaly Posted August 11, 2022 Author Share Posted August 11, 2022 Thank you!!! Link to comment Share on other sites More sharing options...
Arthur Posted August 11, 2022 Share Posted August 11, 2022 It may actually matter which binder you care to activate. The gum will activate with alcohol, the Dex will activate with water. Link to comment Share on other sites More sharing options...
Mumbles Posted August 15, 2022 Share Posted August 15, 2022 I can't say for sure I've used that exact formula, but I have used somewhat similar ones before. They did burn pretty fast. I think it's from a combination of a couple of factors. Using flash grade dark flake tends to make stars burn faster when comparing against something like atomized aluminum or magnalium, which tends to be used in coarser meshes. One thing to note about that particular formula, and the very similar ones floating around, is that it doesn't have any chlorine donor. I was never overly satisfied with the color saturation and the burn speed is relatively high. You can find other formulas that are fairly similar to this one, but with the inclusion of a chlorine donor. Those behaved more according to what I expected. Most chlorine donors tend not to burn overly well on their own. I think this slowed them down to something more normal, and improved the color. Link to comment Share on other sites More sharing options...
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