Resin?
- Thread starter SVMOONDANCE
- Start date
I need to replace the fore deck and gunwhale core and would like to know so I can use the same resin that way I can get a strong secondary bond.
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I'd suggest calling Catalina Yachts customer service.
http://www.catalinayachts.com/
Catalina Yachts Florida
7200 Bryan Dairy Rd.
Largo, Fl 33777
727 544 6681
http://www.catalinayachts.com/
Catalina Yachts Florida
7200 Bryan Dairy Rd.
Largo, Fl 33777
727 544 6681
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I would suggest obtaining a copy of the C-22 Tech Manual where others have documented the repair complete with photos and step by step instructions. Also a visit to the WEST epoxy site has loads of information on the correct way to repair fiberglass boats and the reasons why you don't use polyester resin to repair a fiberglass boat. I've followed their advice for 30+ years going back to my first C-22. Polyester resin is great for building, lousy for repairing. Epoxy is the only way to go.
There are many ways to go as well as epoxy. I find that asking West if their product is better than another would be like asking a Chev. dealer if a Chev. is better than a Ford.
What part are you actually describing as "gunwhales"?
I have replaced my entire deck core. I turned the boat upside down and did this from the inside to preserve the actual original deck structure. For my repairs I used polyester laminating resins, added chopped glass fibres and fumed silica to add the mechanical strength to the laminating resin. Improtant to precoat the plywood with straight catalised resin first and let it go off. Then bond the treated plywood pieces to the original fiber glass skin using the mixture above. Then just applied CSM and laminating resin in layers to build up the other side of the skin.
I used polyester resin due to the fact that this was done from the inside of the boat so it "should" not see the weather as well as the original boat was built using polyester resins. Epoxy is great but the budget may take a serious knock.
This has been my experience as well. Me and ester resins in general just don't seem to get along.
@SVMOONDANCE It is my understanding is that our boats were built with polyester, but I'm done with poly for repair work. YMMV of course, Greg obviously has no problem with poly! Either way, if you need a lot of resin (sounds like you do) and you're on a budget (who isn't), check out US Composites.
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I'm going to attack this job from the top. I have a pretty good knowledge of the different types of resins having done fiberglass repair professionally as a job. The budget right now is only going to allow me to use poly (as that seems to be what was used in the original layup) and not epoxy. The one thing I am going to spend a little extra on is the core material. I have a local fiberglass supplies dealer that has pretty good prices on Coosa board so thats the game plan. The skin will be remove in one piece and reused and all seams will be done in 1708 tape and re gelcoated. Would think about going from the inside if I had the resources to turn the boat over.
Resins, materials, and fabric are aval. at Express Composites (expresscomposites.com). Good products and they know their stuff. Stay away from resins packaged to sit on a shelf for general use. It would be best to make a simple bonding test before repairing regardless of what resin you use. Many manufacturers will add a promoter to their resins to get faster cure times and the ability to pull the part sooner. This at times can and have made it impossible to bond anything to it without using a special primer. I have built and repaired composites for 30 plus years, still have friends in the business and have experienced this only 4 or 5 times. Two of these were repairs that were a couple of years old were failing on the new owner. Of course, the previous owner had never had a repair fail -- while he owned the boat. The guys that have repaired their boats for many years without a simple bonding test are unknowingly playing Russian Roulette. As to the mech. bonding: poly is more than adequate for many repairs. It is "poorer" in adhesive properties than expoy, but not poor in adhesive properties. Most of the bonding tests w/ poly pulled apart at the 1st or 2nd layer of glass of the part. Nothing I know of could improve that. As to working with resins: An expoy can have the benefit of easier controlled gell time. If working in the summer heat this can help. You can also use polyester and a summer catalyst to give better gell times. I also use the "summer catalyst" when doing something like recoring decks as an aid in limiting the heat due to mass. Buy your materials from a source that knows their stuff.
So what resin is more than adequate to recore your deck. The weakest point of this will be (in most cases) at the core to laminate bond. The only time I have had the bond of poly to plywood fail was when I failed to sand the ply w/ 36 grit. I sanded and retested and the plywood then pulled apart not the bond. Save a ton a money for a recore job and use a good polyester.
So what resin is more than adequate to recore your deck. The weakest point of this will be (in most cases) at the core to laminate bond. The only time I have had the bond of poly to plywood fail was when I failed to sand the ply w/ 36 grit. I sanded and retested and the plywood then pulled apart not the bond. Save a ton a money for a recore job and use a good polyester.
If interested I have lots of leftover material from past jobs including foam and balsa in verious thickness. You can P. M. here or email mmehne47@hotmail.com. If you do go w/ Coosa board I would be interested in what you thought of it. I would also recomend that you use a vac. bag to pull and hold the core down. The shapes of boat decks and the stiffness of the cores make leaving no voids difficult.
I ended up cutting the 6mm plywood into strategically shaped jigsaw puzzle exactly because of the compound curves in the deck structure. That and lots of bricks left over from a paving job I way overestimated for! Really important to avoid any possible gaps or voids in the new structure.
I don't actually think we have "coosa" board as you call it locally in SA. Looks quiet interesting from photos you posted.