Guest Posted November 3, 2013 Share Posted November 3, 2013 maybe spelling lessons as well. 30yo boat built using polyester resin. Rebuild it using Polyester, Vynelester or Expoy? Rebuilt materials include ply, foam, std glass and some carbon. I'm getting some saying vynelester and some epoxy, none have said use straight polyester. Thoughts, experiences, what are the theories? Ta Link to post Share on other sites
Island Time 1,240 Posted November 3, 2013 Share Posted November 3, 2013 Epoxy!! Good article here; http://www.multihulldesigns.com/pdf/Why%20Epoxy%20is%20Preferable%20to%20Vinylester%20and%20both%20are%20Preferable%20to%20Polyester.htm Matt Link to post Share on other sites
wheels 543 Posted November 3, 2013 Share Posted November 3, 2013 The polyester of today is in fact vinyl ester. Polyester disappeared back in ruffly the late 70's. That is what was prone to Osmosis. Vinyl Ester is not. Epoxy is slower to cure of course, but far superior in strength, impact resistance and will stick to old GRP OK. It allows you to build up with thinner laminates than you would be able to with GRP to gain the same strengths. Link to post Share on other sites
wheels 543 Posted November 3, 2013 Share Posted November 3, 2013 To add to that, Vinyl ester does not have a good "bonding" ability like Epoxy does. Epoxy "adheres" far better and that could be essential in bonding with Carbon. Cloths, or more specificaly the chopped strand mat used with Ester resins had a special coating to allow the Ester to "wet" and adhere to the Glass better. That coating is not found on Carbon or ordinary Glass cloths. Link to post Share on other sites
Ptown 14 Posted November 3, 2013 Share Posted November 3, 2013 After the recent work I've done I'd definitely say vinylester. Cheaper and seems super strong/hard - don't know too much if this means stiff but I'd imagine that that comes back more to the cloth/lay-up you use. Boat builder was quite impressed with it... I also quizzed the boat builder who did the previous work on the boat on what was used and his response was that the conventional wisdom is vinylester over either polyester or older vinylester. Getting hold of it was trickier than epoxy. Link to post Share on other sites
wheels 543 Posted November 3, 2013 Share Posted November 3, 2013 Oh and one more really important point. If you are going to be carrying out multiple layering, as in Glass cloth over either a ply or foam or whatever, then a layer of Carbon for strength and stiffness, Epoxy is far superior at adhering to each previous layup and even when clothes/substrates are layed up all at once, Vinyl Ester has a much poorer performance in stopping shear between layers. Especially in a situation like Glass and Carbon, where there are very different stretch/tensile rates. Epoxy gives a far superior bond between layers. Link to post Share on other sites
Guest Posted November 3, 2013 Share Posted November 3, 2013 Given a choice I'd use epoxy but is that the best option to bond to the existing boat? Some say No use vynelester, some say yes epoxy is fine. That's one of the problems I'm finding in this rebuild, NZ is too small to get good advice that doesn't have a bias to it. Too many tied to specific suppliers or techniques so that's what they tend to promote. Link to post Share on other sites
Ptown 14 Posted November 3, 2013 Share Posted November 3, 2013 To be fair I did also read that epoxy has very good mechanical bonding (to existing cured resin) properties so I reckon either way your fine but then cost comes into it. Link to post Share on other sites
Guest Posted November 4, 2013 Share Posted November 4, 2013 epoxy will bond fine to a poly layup of your age. finish the surface with a 38 grit grinding disc, or 40 git orbi. it will defiantly key to the exposed fibres. And if you using ply as your secondary structure epoxy would be the choice Vynelester resin is fine to use as well. It is typically thinner in viscosity than epoxy and can drain from the heaver cloths weave and doesn't bridge the gaps as well so to speak, so you will need a tissue or 225g csm down first. Note; it needs a descent film/thickness to self promote and go off properly. so just giving something a resin coat can backfire on you. As some of you know ynot and I have acquired wrecreation. I'm an epoxy fan, but am considering vynelester for the hull shell repairs, and anything that will/would be fully glass enclosed. then epoxy to anything timber I can get a lighter and stronger laminate with epoxy buy eliminating the chop strand matt/tissue. but do I just match the existing layups ? Link to post Share on other sites
dkd 3 Posted November 4, 2013 Share Posted November 4, 2013 For what my thoughts or experience is worth .... All the repairs we have done to the old Trainsmash which includes new frames and extensive repairs to previous damage etc etc etc ... (the list goes on) everything has been done with Epoxy and nothing but epoxy. I would not use anything else but then the boatbuilder has recommended that nothing else was used. Even the filler used has been epoxy. For the small difference in price the peace of mind is invaluable Link to post Share on other sites
Guest Posted November 4, 2013 Share Posted November 4, 2013 I spoke to a mob I trust and who has no barrow to push either way. They said - If using lots of wood - epoxy, no VE If using stuff not wood - epoxy or VE If using choppy - VE (and No I'm knot) If using .... and went in to lost of other scenarios which all ended up with - epoxy or VE. I said I'd heard wiping old polyester with Cobalt was a good idea if trying to stick epoxy to it. They said knot really as you run the risk of having excess cobalt in the bond potentially weakening it. I said I'd also heard of using styrene instead of Cobalt. Again they were fans as you run the risk of thinning the resin in the bond again weakening it. They said they would recommend a hell good sand with grunty paper, a good wipe with Acetone or similar and once that has had plenty of time to gas off bond away with epoxy. So with all that in mind, responses her and from a couple of other places I'm making the call of 'epoxy it will be'. Happy about that as I have lots of that poxy resin, have used lots of it in the past and it's easier to spell. Link to post Share on other sites
Changed 10 Posted November 5, 2013 Share Posted November 5, 2013 Interesting reading about all the different advice. I have been told that it helps to prime old layers with resin before applying the new build. The primer is a mix of resin with glue powder to colour which was then painted on prior to laying up. Seemed to work as the bonds never let go. However I've only ever used epoxy for repair or changes. New items such as instrument recesses or deck blocks have been made out of polyester. It goes off quick which saves the vacuum pump. Link to post Share on other sites
Guest Posted November 5, 2013 Share Posted November 5, 2013 Again they were fans as you run the risk of thinning the resin in the bond again weakening it. Opps, amongst all the others there is a nasty typo in that. That should read - Again they were NOT fans as you run the risk...................... I've heard that as well C. I didn't ask them about that but I will next chat. Link to post Share on other sites
dogzballz 0 Posted November 25, 2013 Share Posted November 25, 2013 real boats a built from epoxy laminates,just keep chopping & start from scratch with a epoxy carbon laminate,no confusion then. Link to post Share on other sites
Recommended Posts
Archived
This topic is now archived and is closed to further replies.