Resin Types In Catamaran Construction

[clockwork orange]

Originally Posted by neilpride

Julian is a clever guy, for sure, but if you keep reading the thread, this pops up.

Prior to glassing the plug (with polyester to get a vacuum seal) I took the opportunity to pre-fit the foam, by screwing into the plug, yes brutal, but the polyester/CSM/cloth/gelcoat will cover all ills.

I'm not sure what this means when the whole thread talks about epoxy and carbon.
Or this layup schedule its just to make the mold?
Maybe i'm wrong.

Generally, a plug, which is the male pattern that you make a female mold from, is not built from expensive materials because you are just going to dispose of it when you have pulled the mold. It just needs to be a perfect representation of the shape and finish. The mold itself will be made of materials and laminate schedule consistent with how it will be used, ie, a mold that will go into an oven will use different resins for example than one used for room temperature hand layup if this makes sense.

[CaptainRivet]

Originally Posted by s/v Jedi

Yes, vinylesters I googled are in the 8000psi range just like epoxy, a little stronger maybe.

It’s basically to get away from polyester. In stretch I understand polyester breaks at 1% stretch, while fiberglass is 6%, so the resin breaks before fiberglass was fully loaded. Epoxy and many vinylesters are in the 6% range so a good match.

Also, epoxy is easier to work with than vinylester. Easier with temperature and is shelf stable for years while vinylester only for months.

Sorry it’s vice versa, VE is much easier to work with then epoxy.and saver as you smell VE and can judge your mask filters well while epoxy you don‘t smell. When he laminated inside he used fresh oxigen supplied from outside the boat.
I restored and re-enforced my whole underwatership with VE in 7 month under guidance and survialance of an excellent fiberglass specialist and boat builder who at the same time fixed my broken structure inside (all only glued stringers and bulkheads cracked or detached from the hull due to an 8m wave broke on one hull) with epoxy. Due to him and the datasheets he showed me the epoxy he used inside had 10% more tensil strength (but +400% then the PE resin FP used) then the VE for triple the price (the VE I used on the underwatership). Inside he used the best available epoxy to make it as strong as possible (and used 50l of it) while for the underwatership the 240l VE I used the price played a role and the VE was 390% stronger then the PE under it anyway, so overkill anyhow but that underwatership is now still light but very strong and won‘t get any osmosis.
It’s now that strong that I can lift my Lavezzi on bow BB and stern STB only while a standard Lavezzi will break apart doing that.we done that during structural test and the insurance surveyor present only allowed that test after my specialist gave him a written declaration he calculated that and it will hold. Surveyor also mentioned in the survey he didn‘t see such a excellent quality work in the last 10 years.
I had to use the Epoxy from inside on a small part in the end as the VE used was not available anymore and to work with the epoxy was a major pita compared to VE. that pita that the boat builder laminated that little part in the end, so it matches the good quality I done with the VE he said as he saw me struggling.

[Redreuben]

I’ve used vinylester for pools and spas and also yachts, in both cases the shop had a schedule of bubbling dry air through the resin to keep it mixed and in solution vastly prolonging the shelf life.
I know this is weird but I like the smell of VE, it’s the molasses of resin.

[s/v Jedi]

Originally Posted by CaptainRivet

Sorry it’s vice versa, VE is much easier to work with then epoxy.and saver as you smell VE and can judge your mask filters well while epoxy you don‘t smell. When he laminated inside he used fresh oxigen supplied from outside the boat.

I can’t get my head around this. Are you saying that:

- Vinylester has a longer shelf life than epoxy?
- Vinylester can be used in a larger temperature range than epoxy?
- you actually think oxygen supply requirement is easier than nit needing it?

I still believe my statement was correct and it is not vice versa

[Chotu]

I'm with Rivet and Reuben.

Health issues aside, it's way easier to work with the "esters" because you have so much more control using a catalyst.

Also, they go off as fast as you want and get the job done in a few hours instead of overnight.

Significantly easier to use and faster.

I suspect anyone trying to make a profit would use these even if they cost twice as much as epoxy. Because you save so much time. And time costs much more than the materials.

I had to make some steering system modifications and adjustments a couple weeks ago. I did them in vinylester and it took me a grand total of about 2 hours. And that includes the painstaking tight tolerance grinding I did. that doesn’t include the couple hours that I let it sit there to cure though. I just hung out on the couch and waited for that.

Shelf life is definitely less however. I get about a year out of vinylester or polyester. what happens when they go past prime is they solidify on their own. A very slow curing takes place over that time.

[sailhand]

Built in both epoxy and esters since 94. Now allergic to epoxy, health issues. Vinyl is my resin of choice. I use unwaxed for all structural components which gives a more reliable bond in my opinion. Also multitudes faster to build in. I mix 20 litre pails of my own bog blend and fillet blend. Takes no time and I don't touch qcell or cabosil etc for months sometimes. Laminate design is crucial when chasing ultimate strength to weight ratios. Finite element analysis will help a lot more than resin type here. Elongation is a major consideration, you tackle it in two directions, minimise elongation of fibres by correct design and match your resin elongation to your fibre. I recently watched a build where epoxy builders used peel ply on unwaxed ve. They also mixed cabosil with ve to help hold glass on vertical surfaces when laminating. It was a disaster and completely unnecessary. Whatever resin you use learn how to use it properly. Unwaxed ve doesn't even need to be sanded for secondary bonding let alone fillet or bog as you get chemical bonding on the uncured surface. Im no chemist but basic chemistry would suggest cross linking of polymers at a molecular level would be stronger than secondary mechanical bonding. Wet on wet is the epoxy man's mantra, with ve everything is basically wet on wet even six months later its still wet on wet.
I think the best thing to do is not listen to people that don't know what they are talking about, especially me, and get the true facts from diligent research. Ian farrier had problems with resin infused beams separating under test loads. He tried many epoxies to no avail and eventually solved the problem with vinylester which he wrote a paper about. I would always use gel coat if l could make everything in moulds. I'm not sure about the relevance of weight issues with gelcoat any more especially with the option of resin infusion. The issue with gelcoat is the availability/construction of molds/tooling. The lightest boats l know of are infused from molds even my own dinghy. For custom one off builds ve is superior as far as process is concerned. Hardly any sanding at all until you get to the fairing, no peel ply, no washing off wax, no keying the surface for secondary bonding. I was involved briefly in a build once in west system where I could walk around and peel off tapes where the surface was not prepared correctly. Unwaxed ve has none of these issues, I am thankful that I became allergic to epoxy and was forced to use ve as I now build things much much quicker and stronger. There will always be a place for epoxy especially with carbon structures built close to their breaking loads, also you have a universal repair resin with a much longer shelf life if you are going remote cruising. Epoxy generally has better mechanical bonding properties although a good ve will out gun a poor epoxy every day of the week. Building from a mold allows you to produce a light structure with basically no fairing. Fairing and painting is heavy as well, especially with an unfair build, I've seen inches of bog over huge areas trying to get things fair. I've also seen a master craftsmen basically go straight to high build, no fairing compound. He was a master at strip planking and using a jack plane, and he was 72 years old, don't make em like that any more.
That's my two cents which should be valued at about two cents below market value, ie nothing. Resin is way down the list in my opinion, core is a lot more important. Polyester and balsa, don't stop running to even glance over your shoulder, just don't look back. What about overall design like bridgedeck clearance , overall weight, hull shape, general arrangement, mini keels or daggers kick up rudders, shaft, sail drive or outboard etc. There are millions of poly boats all around the world and most of em float. Good luck and fair winds whichever you decide on. The only thing I know for sure is cruisings great and building sucks!!!!

[Chotu]

Wow, sailhand.

I had to double check and see if I made that post or you did. I couldn’t agree more with every word in there.

[Steamer]

[QUOTE=mattinacan;3743609] They are both light and performative and similarly priced. The Outremer is constructed with vinylester and polyester resins, and the ITA is 100% epoxy. They both have carbon bulkheads and reinforcements, foam core and eglass. I know that epoxy is the stronger resin, but Outremer has been around for many years building great boats and has a solid reputation. I also like the Outremer styling/layout more but should I go with the epoxy boat? Is this a big difference? Am I overthinking this? My intent is world cruising/liveaboard. /QUOTE]

To put it simple: if You find it important for any reasons to have the NAME behind Your boat, then go for Outremer. If You are building the boat for You and pay no attention to the "market opinion", then go for ITA. BTW, if You compare materials then take ALSO a deeper look at what You define as a "foam". The better materials are used the better outcome should be!

Good luck with Your choice!

[malbert73]

My 1987 boat is built of vinylester (Tartan was ahead of the curve) and the hull still looks amazing. No water intrusion. No blisters. Full hull core is dry (except for one small spot where a prior owner screwed into inner skin poorly)

I’d go for that

[Flobble]

Surely, it's about so much more than the construction materials? Layout and design, quality of manufacture, builder's willingness to accommodate specific requests, after-sales service, warranty and the builders' ability to stand behind it, reputation, likely resale value, potential speed of resale, likelihood of access to suitable repair and maintenance facilities in your cruising grounds of choice etc, etc.

[noelex 77]

Originally Posted by Flobble

Surely, it's about so much more than the construction materials? Layout and design, quality of manufacture, builder's willingness to accommodate specific requests, after-sales service, warranty and the builders' ability to stand behind it, reputation, likely resale value, potential speed of resale, likelihood of access to suitable repair and maintenance facilities in your cruising grounds of choice etc, etc.

These are all important questions, but even if all the factors mentioned are perfect, should you buy a catamaran made from poor quality materials?

[CaptainRivet]

Originally Posted by noelex 77

These are all important questions, but even if all the factors mentioned are perfect, should you buy a catamaran made from poor quality materials?

true...a friend of mine surveyed for the insurance lately a outremer 51 where the mastfoot broke through the bridgedeck, was a production issue...since then nobody then outremer is allowed to get near to that catamaran