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#1
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Vinylester Resins
Dear Group,
Has anyone in the group used vinylester resin to do any boat building? Some manufacturers are claiming very close performance to epoxy because of epoxy resins being added to the vinylester. Are these claims true? Thanks for any help. M Russon |
#2
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No, the claims are not true in so far as the epoxy being *in* the
vinylester resin. What may have some validity is the claim that vinylester resins are "very close" to epoxy when the end product is an all fiberglass boat hull. The chemical makeup of polyester resins (of which vinylester is a family member) are a concoction of anhydrides, polybasic acids, glycols and styrene, plus an 'accelarator' of cobalt napthanate. Once a small percentage (1 - 2 % by weight) of Methyl Ethyl Ketone Peroxide is added (called the "catalyst"), a chemical reaction occurs as the result of rapid oxidation. Epoxy resins are quite different chemically, baed largely on Bisphenol products and Ethyl Hexyl Glycidyl Ether. Once mixed with a "hardner" (in a ratio of anywhere between 25 to 100 % by weight) a chemical reaction occurs due to molucular bonding. It's ludicrous to supose that these two vastly different chemical 'systems' could be made to work together in one product. If you can find a manufacturer who claims to have both systems in one product, I'd love to hear about it! However... Vinylester resins exhibit many of the properties that are associated with Epoxies when describing qualities that comprise a sound fiberglass hull, namely: High chemical and corosion resistance, high elongation flexibility, and reduced water permiation. Vinylesters are the 'best' of the polyester resin family, and are (of course) priced accordingly (albeit considerably less than Epoxy). Remeber that all polyester resins are *not* very good adhesives, which is primarily why early attempts to sheath wooden hulls with fiberglass failed; ultimately the bond between the wood and the resin let loose, water got to the wood and... So: If you'll be laying-up a fiberglass hull and can stand the styrene smell, Vinylester resin would be a sound choice, especially for traditional e-glass materials. Mike Worrall Los Angeles |
#3
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#4
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Hetron is a tank liner coating not a laminating resin. It is used to coat
the inside of caustic chemical and petroleum tanks. Closer to vinyl ester floor paint than real epoxy. Somewhat flexible and cures with MEKP. Some Bromated Epoxy vinyl esters are used with reinforcing to build tanks and high end bathroom fixtures but generally to low a modulus for boat building. It is very resistant to permeation though. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "MRusson" wrote in message ... On 7 Sep 2005 22:04:46 -0700, wrote: It's ludicrous to supose that these two vastly different chemical 'systems' could be made to work together in one product. If you can find a manufacturer who claims to have both systems in one product, I'd love to hear about it! Mike, This is the stuff i was mentioning in an earlier post. Is this an epoxy-vinyl ester blend? http://www.ashchem.com/ascc/compoly/HighPerfEpoxy.asp Mike Worrall Los Angeles |
#5
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I gladly and humbly defer to Glenn on this one. I'm not a chemical
engineer, nor do I play one on TV, but I thought I had a pretty good grasp on the basic chemical differences between the polyester family of resins and the epoxies. It appears that the Hetron contains some quantity of Bisphenol A, a major component of most laminating epoxies. I could not locate the MSDS on the Ashland site - this would have been instructive in deducing what perecentage of BPA is in the brew. (For reference, West Systems all-purpose "105" epoxy resin is 50% BPA) What puzzles me is the ability of MEKP to 'harden' the BPA, especially if the BPA comprises more than a percent or two of the Hetron product. My understanding is (was?) that a member of the Amine family is required for the cross-linking (harding) of true 'epoxy' resins. At any rate - as Glenn suggests - Hetron may not be a suitable resin product for boatbuilding. Mike Worrall Los Angeles |
#6
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Soooo ...what about hardness as compared to epoxy, and what about vinylester
as a gap-filling glue? If the hardness is similar or higher than epoxy but the elongation and shear strength is not lower than epoxy, then that would be great. If the vinylester can and will bond like epoxy, that that would be great. When I say 'bond like epoxy', that means non-shrinking gap-filling and stronger than the wood ...the wood fails before the glue joint fails when you perform destructive tests. If vinylester can't live up to these standards, then I'd stick with epoxy (haha). Brian wrote in message ups.com... No, the claims are not true in so far as the epoxy being *in* the vinylester resin. What may have some validity is the claim that vinylester resins are "very close" to epoxy when the end product is an all fiberglass boat hull. The chemical makeup of polyester resins (of which vinylester is a family member) are a concoction of anhydrides, polybasic acids, glycols and styrene, plus an 'accelarator' of cobalt napthanate. Once a small percentage (1 - 2 % by weight) of Methyl Ethyl Ketone Peroxide is added (called the "catalyst"), a chemical reaction occurs as the result of rapid oxidation. Epoxy resins are quite different chemically, baed largely on Bisphenol products and Ethyl Hexyl Glycidyl Ether. Once mixed with a "hardner" (in a ratio of anywhere between 25 to 100 % by weight) a chemical reaction occurs due to molucular bonding. It's ludicrous to supose that these two vastly different chemical 'systems' could be made to work together in one product. If you can find a manufacturer who claims to have both systems in one product, I'd love to hear about it! However... Vinylester resins exhibit many of the properties that are associated with Epoxies when describing qualities that comprise a sound fiberglass hull, namely: High chemical and corosion resistance, high elongation flexibility, and reduced water permiation. Vinylesters are the 'best' of the polyester resin family, and are (of course) priced accordingly (albeit considerably less than Epoxy). Remeber that all polyester resins are *not* very good adhesives, which is primarily why early attempts to sheath wooden hulls with fiberglass failed; ultimately the bond between the wood and the resin let loose, water got to the wood and... So: If you'll be laying-up a fiberglass hull and can stand the styrene smell, Vinylester resin would be a sound choice, especially for traditional e-glass materials. Mike Worrall Los Angeles |
#7
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Brian D wrote:
Soooo ...what about hardness as compared to epoxy, and what about vinylester as a gap-filling glue? If the hardness is similar or higher than epoxy but the elongation and shear strength is not lower than epoxy, then that would be great. If the vinylester can and will bond like epoxy, that that would be great. When I say 'bond like epoxy', that means non-shrinking gap-filling and stronger than the wood ...the wood fails before the glue joint fails when you perform destructive tests. If vinylester can't live up to these standards, then I'd stick with epoxy (haha). Vinylester and polyester are laminating resins, not adhesives. They are not a substitute for epoxy in bonding applications. |
#8
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On Sat, 24 Sep 2005 19:05:17 -0700, "Brian D"
wrote: Soooo ...what about hardness as compared to epoxy, and what about vinylester as a gap-filling glue? If the hardness is similar or higher than epoxy but the elongation and shear strength is not lower than epoxy, then that would be great. If the vinylester can and will bond like epoxy, that that would be great. When I say 'bond like epoxy', that means non-shrinking gap-filling and stronger than the wood ...the wood fails before the glue joint fails when you perform destructive tests. If vinylester can't live up to these standards, then I'd stick with epoxy (haha). Brian Just some info for you about Corezyn Vinyl Ester resin. The numbers speak for themselves. http://www.geocities.com/duke_of_ur1/Lenox/ Click the vinyl ester resin link to the left. I have liked vinyl ester resins for years, and don't see why more people don't use them. They have, in most cases, superior results and the price is better. Thats my 2 cents worth. I like the Interplastics Corezyn VE-8117. It is a great resin. M Russon |
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