LiamPyro Posted February 28, 2015 Posted February 28, 2015 Hi, I have purchased the chemicals to make some red metallic fueled color stars (I'm going to try Buell Red) but I have a few questions. First, what is a good solvent to use? I do not want to use acetone. Alcohol/water seems like a good idea, as it would activate both the dextrin and red gum but not the parlon (I don't want to deal with messy parlon "strings"). I think MgAl is moisture sensitive to some degree like Mg, so wouldn't it pose a problem if water is being used as a solvent? Also, is there anything else I should know about color stars? Thanks!
Xtreme Pyro Posted February 28, 2015 Posted February 28, 2015 (edited) You will be fine using a mixture of 75% water / 25% Alcohol. I roll buell red all the time.. Never had issues. Edited February 28, 2015 by Xtreme Pyro
LiamPyro Posted February 28, 2015 Author Posted February 28, 2015 Thanks for the reply! I know this probably makes no difference, but what type of alcohol is usually used? I always use isopropyl alcohol 70% concentration plus water, and just work it out so that I end up with the correct amount of water/alcohol.
MarkU1967 Posted February 28, 2015 Posted February 28, 2015 If dextrin is to be the binder then 25% alcohol is probable pushing the limits. I use denatured alcohol as may most likely do.
enanthate Posted February 28, 2015 Posted February 28, 2015 If dextrin is to be the binder then 25% alcohol is probable pushing the limits. I use denatured alcohol as may most likely do.Who does NOT use the 25/75? I've used more than 25% plenty of times. What's the deal with parlon? I love working with it, quick and easy. The only downside is the cleaning of the container afterwards, which is why I use separate containers for separate colors.After a few batches you get the hang of it, and will make very little mess. You will quickly figure out the desired consistency for cutting, which makes the process smooth and easy. And the stars come out very nice in shape and size, dried in less than an hour.
LiamPyro Posted February 28, 2015 Author Posted February 28, 2015 Do parlon bound stars burn differently than dextrin bound ones? If not, I may give that a try as quick drying time is a big plus. Although I don't like working with acetone. BTW what is so special about 25/75 alcohol/water?
Bobosan Posted March 1, 2015 Posted March 1, 2015 Do parlon bound stars burn differently than dextrin bound ones? If not, I may give that a try as quick drying time is a big plus. Although I don't like working with acetone. BTW what is so special about 25/75 alcohol/water? The alcohol supposedly breaks the surface tension of the water allowing the material to absorb moisture easier and quicker.
nater Posted March 1, 2015 Posted March 1, 2015 The parlon can sometimes burn with a little orange slag which can dirty up the color. Screening the coarse chunks of parlon can help prevent this, you can also overwet the comp with acetone to fully dissolve the parlon and then allow the solvent to dry out before cutting the stars. Other solvents can be used as well and make stars nearly waterproof, but are just as nasty to work with as acetone. Troy Fish has an article in Pyrotechnica VII which describes the use of Parlon and MgAl for fast drying and moisture resistant stars. He describes the pros and cons of various solvents to use to dissolve the parlon. This article served as the inspiration for Gary Smith and then Ned's work on screen slicing parlon bound stars.
nater Posted March 1, 2015 Posted March 1, 2015 Who does NOT use the 25/75? I've used more than 25% plenty of times. I don't. When making dextrin bound stars, I typically use a dextrin "liquor" as mentioned by others and myself in other threads. The times I don't use that method or Ibuse SGRS, I just use plain water as the solvent and leave the alcohol on the shelf.
LiamPyro Posted March 1, 2015 Author Posted March 1, 2015 The alcohol supposedly breaks the surface tension of the water allowing the material to absorb moisture easier and quicker. I see, that makes sense. It would also make them dry a bit faster.
LiamPyro Posted March 1, 2015 Author Posted March 1, 2015 Other solvents can be used as well and make stars nearly waterproof, but are just as nasty to work with as acetone. Is this a preferable quality? I guess I can see the advantages, if you live in a humid area or you're making strontium nitrate based stars. But wouldn't the prime not stick as well?
nater Posted March 1, 2015 Posted March 1, 2015 It all depends on your storage conditions and duration. I don't see the need to make stars waterproof for my needs. The other solvents he mentions take longer to dry, acetone works well for me and is perfect for events when we build and shoot the same weekend. To be honest, I have moved away from parlon and acetone and have been making colors using phenolic resin as a fuel and the binder with alcohol as the solvent.
Mumbles Posted March 2, 2015 Posted March 2, 2015 Who does NOT use the 25/75? I've used more than 25% plenty of times..... Most of the people who know what they're doing. I'm sure you'll keep doing your own thing though. When working on reasonable scale the amount of alcohol becomes expensive and noxious without providing much of a benefit. It can help when starting stars when rolling, and breaking the surface tension of certain compositions. Even here, the amount is generally 10% or less. I am with MarkU1967 on this. 25% is overkill, and I think is a carry over from something in Dave Blesser's book. People seem to assume it's good for everything erronously. At this concentration, you're going to start decreasing the activation of dextrin in my opinion. They may still work alright, but who wouldn't want stars as hard as possible? For what it's worth, I've never noticed much of an increased drying rate either. A drying box can dry water bound stars in a few hours to overnight if time is a concern anyway. I'm still waiting for the day someone has an accident with acetone or alcohol vapors. It's a when, not and if. Acetone has a wider explosive limit than natural gas, and both ethanol and isopropanol are even worse. 1
enanthate Posted March 3, 2015 Posted March 3, 2015 I'm sure you'll keep doing your own thing though. Yup, like im the only one using 25\75.Lol.
Maserface Posted March 3, 2015 Posted March 3, 2015 Personally, I would avoid using alcohol in red gum containing compositions- I dont care much for the working quality of red gum; also ive never had any problems with using just water to bind compositions, even with high charcoal/metal contents. It wouldnt be worth the time (to me) to weigh and mix water and alcohol, much less the additional cost and fumes!
Carbon796 Posted March 4, 2015 Posted March 4, 2015 Yup, like im the only one using 25\75.Lol.Im sure some people may use that ratio, for helping to start cores, for rolling. But, for cutting or pumping stars, that are meant to be water bound. It's really more detrimental than anything.
LiamPyro Posted March 5, 2015 Author Posted March 5, 2015 Alright, I'm definently sticking to plain water from now on. I always thought it was beneficial to add alcohol, but I guess not. BTW, fumes aren't much of an issue for me because I've got a fume-respirator and my workshop has a big ventilation fan.
schroedinger Posted March 5, 2015 Posted March 5, 2015 Adding alcohol to your water is used to brake surface tension, specially interesting with charcoal stars.
nater Posted March 6, 2015 Posted March 6, 2015 I have not noticed a big enough improvement with alcohol added to the water when wetting a comp with lots of charcoal. I use plain water and just keep stirring until it is mixed. Cut stars will go from too dry to soup quickly, so it pays to go slow anyway.
schroedinger Posted March 6, 2015 Posted March 6, 2015 Well i feel that the comp wet much better if some alcohol is added, as the water penetrates the charcoal better.Maybe the reason is also that i use methanol.
stix Posted March 6, 2015 Posted March 6, 2015 (edited) I have not noticed a big enough improvement with alcohol added to the water when wetting a comp with lots of charcoal. I use plain water and just keep stirring until it is mixed. Cut stars will go from too dry to soup quickly, so it pays to go slow anyway. Well i feel that the comp wet much better if some alcohol is added, as the water penetrates the charcoal better.Maybe the reason is also that i use methanol. Why the differing opinions? I've only limited experience, but there is something that I have realised. It's mostly about the charcoal you are using. Obviously more apparent when making charcoal rich compositions. I use paulownia, and have experienced this phenomenon when making the "Spider" comp. Apart from the fact that paulownia is a fast burning charcoal, I decided to try two "wetting" procedures. The first I used (90 water / 10 denatured alcohol - metho), the second (90 Water / 10 Isopropyl alcohol). Using the Isoproplyl, the comp did not "come together" (perhaps it would have in the end) but I was left with whettish charcoal. I let it dry out for a couple of days and wetted with 90/10 metho and it came together fine. Perhaps some charcoals don't need the alcohol because they are not very hydrophobic and/or there are different reactions depending on the alcohol used (as I have experienced). It would be good to have a semi-scientific test to determine the hydrophobic qualities of the charcoal being used. ie. a sprinkle of airfloat on a white plate, spritzed with a water/alc combo solution, and a set of known reactions to look for??? Then at least a basis point could be established for individual circumstances. Sorry if this does not address the op's original question, but perhaps there's something useful there. Cheers. Edited March 6, 2015 by stix
Bobosan Posted March 6, 2015 Posted March 6, 2015 Stix, what percentage ISO (by itself) did you use? There has been discussion on fireworking about certain types of charcoal make a better cohesive mixture when dried. Paulownia tends to have a lot less sap than say, pine or red cedar.
stix Posted March 6, 2015 Posted March 6, 2015 Stix, what percentage ISO (by itself) did you use? There has been discussion on fireworking about certain types of charcoal make a better cohesive mixture when dried. Paulownia tends to have a lot less sap than say, pine or red cedar.. 90% Water / 10% Isopropyl alcohol/Isopropanol. I normally use around 5% dextrin powder mixed into the comp as the binder - so less alcohol, more water ensures the dextrin is activated properly. Although I may start using the dextrin liquor method that others have highly praised. More resinous charcoals would likely require less binder? - I'm not sure how that would relate to how well they take up water. Perhaps using alcohol dissolves the resins, eg. red gum.
Bobosan Posted March 7, 2015 Posted March 7, 2015 Actually, what I meant is the isopropyl by itself. 70%? 90%? 99%? etc. It has been mentioned that a small % of alcohol can break surface tension of the water in contact with charcoal and allow a greater material absorption rate. The alcohol would also cause the resinous charcoals to adhere to itself along with increased absorption of the nitrate and sulfur. Many folks are using eastern red cedar charcoal to make their BP and only using isopropyl alcohol to granulate. It is supposed to produce granules that are hard enough to withstand a great deal of handling without breaking down yet will compact nicely when pressing rockets. I tried a straight ISO granulation with BP made from Paulownia and the dried granules just crushed into powder again easily. The uncooked resins left in certain charcoals is key, or just use the dextrin liquor on less resinous woods like Paulownia.
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