oldguy Posted April 28, 2011 Posted April 28, 2011 Is there any consensus on using PVA as a binder? Pro's, Con's etc.
dagabu Posted April 28, 2011 Posted April 28, 2011 A binder in what? For pyro it is extremely expensive, as a glue, its what Elmers is made from (plus CMC and other fillers). -dag
oldguy Posted April 29, 2011 Author Posted April 29, 2011 A binder in what? For pyro it is extremely expensive, as a glue, its what Elmers is made from (plus CMC and other fillers). -dag Flares, fusee's & the like.$165 for a 55 lb bag is about $3 a lb.My understanding is that it burns off very clean, with almost no smoke, odor, ash residue or dross.
dan999ification Posted April 29, 2011 Posted April 29, 2011 unless im missing something p.v.a stands for poly vinyl acetate. [the glue] i dont know if alcohol is used in other glues, if it is what you mean ive used it thinned with water to bind bp before i made dextrin, it slows it down considerably but would probably suit comps that need retarding,slower fuses, beraq timing, primes. it does burn clean with no leftovers though i only used 2%.dan
Mumbles Posted April 29, 2011 Posted April 29, 2011 Unfortunately, both go by the acronym PVA, of which the acetate is generally not suited toward pyro binding. He did specifically ask for polyvinyl alcohol though, so I don't know where the confusion is coming from. In the industry, they call polyvinyl acetate PVAc, but the public is slow to take that on. I would tend to agree with the statements about it being fairly pricy. A quick look at the places I know carry it, have it for around $10/lb in full bag quantities. This may be a higher grade though as it's food grade according to the MSDS. I honestly don't know much about using these solutions. I have seen a few formulas that utilize small amounts of it, all for pressed items, similar to that patent you posted. I've never made any of them though. You may want to try passfire, as that'd be the best place to get the full spectrum of pyro experience. If you do go down this route, it seems you'll want to find a grade that is soluble in room temperature water. The grade I was looking at lists that it is insoluble in cool water, only hot. I do not know if you can make a solution and cool it for it to remain a solution or not.
oldguy Posted April 29, 2011 Author Posted April 29, 2011 (edited) I agree the abbreviation PVA can cause confusion as it may either stand for Polyvinyl acetate, or polyvinyl alcohol. I am referring to polyvinyl alcohol, not Polyvinyl acetate. Polyvinyl alcohol is discussed as a binder in Pyrotechnic Chemistry (Kosanke Et Al 2004) Chapter 7 page 12 & Chemistry of pyrotechnics: basic principles and theory (Conkling 1985) Page 80. It is also the binder of choice used in "Low-smoke nitroguanidine and nitrocellulose based pyrotechnic compositions" U.S. Patent 6599379 Issued on July 29, 2003 The grade I found (Celvol Polyvinyl Alcohol Grade 540) is soluble in water, but you heat the water slightly to insure it is disolved in total solution.Once in solution, room temps are fine. http://www.celanese.com/celvol_polyvinyl_alcohol.pdf “In adhesive formulations, Celvol polyvinyl alcohols can function as the primary binder or a compounding agent. They bond particularly well to cellulosic surfaces and offer improved water resistance, strength, and resistance to grease and other petroleum hydrocarbons.” Of particular interest to me is that PVA works particularly well with cellulosic materials. In that I am now trying to formulate a low or minimal smoke comp with slightly plasticized microcrystalline NC EDIT TO ADD There is some for sale on ebay fairly cheap. Edited April 29, 2011 by oldguy
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