Potassiumchlorate Posted February 6, 2012 Share Posted February 6, 2012 I'm making some barium chlorate stars again, rolled, and I'm using the shellac as a binder. It seems to be easier to bind with dextrin, but shellac is one of the oldest binders there are in pyrotechnics. It seems like it's hygroscopic when moistened with alcohol, but back when shellac was the most common binder (or even the only one), they just primed the stars with BP, because they didn't have any "hot" metals, and before 1830 or so they didn't have any "hot" oxidizers like potassium chlorate or potassium perchlorate either. Dr. Cutbush's book about pyrotechnics was published in 1825, and potassium chlorate wasn't in common use back then. So why isn't shellac use as a binder more often? Link to comment Share on other sites More sharing options...
Peret Posted February 6, 2012 Share Posted February 6, 2012 So why isn't shellac use as a binder more often?Probably because it's a pain in the ass, as mentioned in other recent threads. It sucks as a binder because it doesn't get sticky until it's almost dry. Also it's expensive, and it doesn't burn well with perchlorate, which is the main oxidizer used these days. Link to comment Share on other sites More sharing options...
Potassiumchlorate Posted February 7, 2012 Author Share Posted February 7, 2012 Hm. I use pure isopropanol, which contains extremely little water and evaporates very quickly. I rolled these in a couple of hours last night. Now they're rock hard, although probably not 100% dry. It's also possible to pump them, but they become more brittle then, and you might have to try some times before you get the amount of alcohol absolutely right. Link to comment Share on other sites More sharing options...
warthog Posted February 7, 2012 Share Posted February 7, 2012 The problem I have gotten with shellac binding is it doesn't actually act like a binder right away. You have to wet it then let the alcohol soften the shellac a bit before proceeding. This makes over-wetting pretty easy to do for the impatient (like me ). I haven't yet rolled any stars but that day draws near from the reports from my roller fabricator. I can hardly wait to try my hand at it too. Link to comment Share on other sites More sharing options...
pyrojig Posted February 8, 2012 Share Posted February 8, 2012 Ha, sounds like me on the last batch of yellow stars. I tried a shellac bound mix and way over shot it. It turned to soup quick. I wasnt patient in my additions of alcohol, it seemed to not take it up fast enough , then before I knew it , I had soup. Thankfully from years of learning the hard way , I kept a portion of the mix as a safety net, and it saved the batch from being a loss. Link to comment Share on other sites More sharing options...
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