Potassiumchlorate Posted January 25, 2012 Posted January 25, 2012 We have discussed shellac/red gum in a couple of threads now. What advantages does red gum have in chlorate compositions that shellac doesn't have? It burns faster, but that doesn't have to be an advantage. However it does not give such a big flame envelope or pure colour, at least not the red gum I have used myself so far.
Mumbles Posted January 25, 2012 Posted January 25, 2012 Red gum is cheaper by a fairly reasonable amount. I've had no problems getting good colors out of red gum fueled chlorate stars. I don't use chlorate stars very often, but when I do I typically used pre-tuned formulas. That may have something to do with it. I'm not starting from shellac formulas and reconfiguring them.
Potassiumchlorate Posted January 25, 2012 Author Posted January 25, 2012 For example: barium chlorate and shellac, where the carbon burns to CO2, is stochiometrically 88:12. The same for red gum is 86:14. However, I don't get nearly such a big and pure flame with red gum.
Mumbles Posted January 25, 2012 Posted January 25, 2012 Are you talking up close, or in the air? Distance can cure many imperfections. I've also never liked to compare something so pure as Barium Chlorate:Shellac to anything else. It's a tough standard to compare anything to. I've said it before, but I'd never use a stoichiometric Barium chlorate mixture as stars in any shell I built. They're too sensitive for the size of shells I like to build. I don't need 20-30hr of work throwing steel in my general direction.
Potassiumchlorate Posted January 25, 2012 Author Posted January 25, 2012 I tried it in a stargun the other night. Quite disappointing.
Peret Posted January 26, 2012 Posted January 26, 2012 As I just mentioned in another thread, according to Shimizu shellac has the highest ratio of hydrogen to carbon of all the resin fuels, so it burns without a yellow flame and is preferred for colored stars for that reason. On the other hand, for some reason it likes chlorate and won't burn properly with perchlorate, whereas red gum works with either. Therefore the answer to your question, what advantage does red gum have over shellac in chlorate comps, is "none", since its performance will not be so good, but in other respects its advantages are "cost" and "works with perc".
50AE Posted January 26, 2012 Posted January 26, 2012 Shellac is a slower burning fuel. Sometimes in formula two are present in a specific ratio. I do it as well. Using plain shellac for blues is good enough, because of their fast burning rate nature. But in reds and oranges where carbonates may be present, shellac should be replaced with some RG to speed up the formula. Try using shellac only in a red SrCO3/chlorate formula. You will usually end with sluggish burning stars and the color will be pale ugly pinkish-red because the molecules aren't excited enough from lack of temperature.
Potassiumchlorate Posted January 26, 2012 Author Posted January 26, 2012 (edited) For red I only use strontium nitrate. A good red Bengal is: Strontium nitrate 65Potassium chlorate 20Shellac 15 This one is slowly burning. For strontium nitrate and potassium chlorate stars the same percentage of both should be used. Stochiometrically they have almost the same ratio with shellac, about 86:14. Though red compositions aren't that sensitive to impurities. Blue and green ones are much more so. Edited January 26, 2012 by Potassiumchlorate
Essohbe Posted January 26, 2012 Posted January 26, 2012 Distance can cure many imperfections. Lol. This is true
pyrojig Posted January 27, 2012 Posted January 27, 2012 Shellac is a slower burning fuel. Sometimes in formula two are present in a specific ratio. I do it as well. Using plain shellac for blues is good enough, because of their fast burning rate nature. But in reds and oranges where carbonates may be present, shellac should be replaced with some RG to speed up the formula. Try using shellac only in a red SrCO3/chlorate formula. You will usually end with sluggish burning stars and the color will be pale ugly pinkish-red because the molecules aren't excited enough from lack of temperature. I had a very similar experience with perch and shellac for a yellow star. It was a pain in the ass to light and even with fence post prime, the stars blew blind on all shells ( hard or soft breaks) . I believe that the culprit was the perch. I should have used kclo3 for that mix, but it was a perch comp. Maybe someone changed it to try and make it safer...( I dont know). *And yes, they are sluggish as well when lit. Almost had a strobe effect, the burn seemed to flicker with a inconsistency.
Potassiumchlorate Posted January 27, 2012 Author Posted January 27, 2012 I don't care much for yellow, but I have used this for yellow Bengals: Potassium chlorate 70Cryolite 15Shellac 15 Pihko Yellow is probably also good, maybe even better: Potassium chlorate 60Sodium bicarbonate 20Dextrin 20 1
pyrojig Posted January 27, 2012 Posted January 27, 2012 (edited) I don't care much for yellow, but I have used this for yellow Bengals: Potassium chlorate 70Cryolite 15Shellac 15 Pihko Yellow is probably also good, maybe even better: Potassium chlorate 60Sodium bicarbonate 20Dextrin 20 The first comp sounds really close to the one that turned to crap on me. I think the author thought it would be safer to sub kclo3 with kclo4 for safety, making the mix a slow burner. Ill have to try the kclo3 as a test against the kclo4 to see if it indeed was the problem maker. I have to say, it was a very bright star when it did light though. * Ive always wondered about the second comp..., is it a slow burner ? I have no experience with the second one, or even know it is a good mix or not. Edited January 27, 2012 by pyrojig
Potassiumchlorate Posted January 27, 2012 Author Posted January 27, 2012 The first one isn't really "deep" yellow, but it's non-hygroscopic and easy to make. The second one is a Pihko composition, probably a bit slow. Though Pihko's compositions are usually very good. The most "famous" one is probably his KP blue.
Nitrato Posted April 9, 2012 Posted April 9, 2012 The first one isn't really "deep" yellow, but it's non-hygroscopic and easy to make. The second one is a Pihko composition, probably a bit slow. Though Pihko's compositions are usually very good. The most "famous" one is probably his KP blue. Pihko yellow is indeed somewhat slow, but fast and easily made with very simple substances. I striked one against match box and throw in the backyard as it ignited readily. http://i242.photobucket.com/albums/ff176/tnitrato/pyro/stars/Pihko%20-%20amarela/DSC01821.jpg http://i242.photobucket.com/albums/ff176/tnitrato/pyro/stars/Pihko%20-%20amarela/DSC01822.jpg It strongly resemble chocolate chips (the darker the dextrin you have is, the closer it resembles), so let it drying away from small kids (and some women). 1
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