Epoxy bad, why?

Bawugna

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This is a question I have wanted to ask for a while now but am finally getting around to it.

It seems that some of you are very ANTI Epoxy. Travis, you seem very much so and I am curious. I had spoken to a boat repair guy in times past who is super PRO epoxy. I am just a boat owner who does most if not all of my own work and have glassed quite a bit of stuff. I have almost exclusively used Polyester and or Vinyl ester resins but have done a few things with Epoxy. The big advantage of Polyester for me is the forgiving nature of it, you can mess up a bit on the ratios and still be fine, epoxy.....not so much.
I am still very interested in why each of you, builders/finishers/boat owners chooses one product over the other.......and just saying "well it is better" is not what I am looking for. Real reasons, concrete differences is where I am headed with this question.

Thanks in advance folks.

Jim
 

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Chances are your boat is polyester, why would you switch to something different?

True, the secondary bond is greater with epoxy, but you're not hoisting up elephants on your wash rails now are you?

Epoxy will cure over polyester, doesn't work out too good the other way around.

It's expensive, sticky and it hates me. That's why I am anti-epoxy.
 

Bawugna

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That all make total sense to me, especially the fact that the boat is Polyester in the first place.

I guess I have to stop the elephant thing:grin:

Thanks Travis for the common sense and practical explanation.
 

kmac

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Without a doubt, epoxy is the best material to build with. It is stronger, more water resistant, and much better at secondary bonding. It is also a lot more expensive, must be mixed in exact ratios, and is very sensitive to working and curing temperatures. Is the extra extra stength worth it? In most cases----No.
 

MASTERENEGADE

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Travis: I think we all find ourselves in a sticky situation after you post in the Mermaid section :shock:
 

nickyp

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Without a doubt, epoxy is the best material to build with. It is stronger, more water resistant, and much better at secondary bonding. It is also a lot more expensive, must be mixed in exact ratios, and is very sensitive to working and curing temperatures. Is the extra extra stength worth it? In most cases----No.
Kmac has summed it up perfectly
 

seahaven

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If you have ever had a boat deck that somebody tried to "seal" by putting a layer of poly resin on it, you know that, like any substance, it has its limitations. Both polyester resin and epoxy resin have their uses. Epoxy resins are much better at attaching to and sealing raw wood, making putties and fillets, and making structural repairs. It is much, much stronger than poly resin, and is significantly more flexible- which is why a layer of poly resin (with no fiberglass) on a plywood boat deck tends to delaminate and break off in sheets, while the epoxy will not.
Epoxy, though, is a PIA for cosmetic repairs, and must be covered by something else (like paint) anywhere it will be exposed to sunlight.

I don't find the exact measuring part of it a big problem. I use a digital kitchen scale set to grams and a cheap calculator- It's easy to get the perfect ratio every time- even in tiny batches. I use throw away 16 oz plastic party drink cups- just chuck it before it kicks, because the cup WILL melt down. It is better to work in small batches, and having the cheap cups that you don't mind throwing away encourages you to not try to "save" a container by making a bigger batch.

I built a stitch and glue skiff years ago, and have done significant repairs since on a number of larger boats. I started with West System- and then realized that it really was not the best product, and was also paying through the nose at the local stores. I now order from Progressive Epoxy Product, Inc. The website is kind of all over the place, but has a lot of great info. Their "Basic No-Blush Epoxy" is awesome, and as the name indicates, you don't have the amine blush problems that West and most other epoxy resins have. (Amine blush is what rises to the surface of the epoxy resin as it cures. If you have ever failed to fully clean it off and then painted- and all your paint peeled off- you know how much it can suck.) Progressives no blush also costs less than West's cheaper quality blushing epoxy.
Its at epoxyproducts.com. I'm sure their are other companies offering similar products, this is the one that I've found and have been happy using.
 
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DBM

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seahaven

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West System is the most well-known epoxy resin company. Its the big brand name. It is a good epoxy, and it certainly performs well. You also pay a premium for their brand name- and there are better, and less costly epoxies out there.
 

Toolate

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No one has mentioned the smell of poly either. Not having done much fiberglass work I was a little aprehensive about signing up for a bunch of close quarters work with the smell of poly. Just seemed like the easier choice for a beginner like me.

Their is all kinds of stuff to read online and in paper about the secondary bonds, water absorption rates, etc. and it is persuasive (towards Epoxy) but in the end, I think most boats are made from Poly or Vinylester for cost reasons and because it just plain works....... and is less expensive.

I appreciate your light hearted hatred for epoxy Travis too. Not much for discussion on it but there isnt much to say I think. Also, a lifetime of experience (or 2? family affair?) has taught you to work with the materials shortcomings and make it do what you need it to do.
 

petrel

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Yes, West is epoxy and I've never found it to all that hard to get right.
 

jwalka51

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I m pretty sure that just putting resin over a plywood deck without glass was the first bad choice, Thats a really bad example. If you used poly resin and a layer of 1.5 OZ matt, there would be absolutly no problem with it.
 

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And if you warm the wood up in the sun for a little bit and mix roughly 10-15% waxed enamel into the resin it will last for years. It's all about bonding to the cellular structure of the wood fibers.

And it's not exactly light hearted, really not a fan of the E

Really dislike having to do projects over and over :?

Best thing for the smell of any type of resin though is some hard candy, like a jolly rancher (yay sour apple!) and when you're all done a peanut butter cup. Smush it all up and roll it around inside your mouth. If you're in the layup shop with a bunch of overspray while playing flange-man (the guy who does the top flange during hull construction, right in the line of fire from the spray gun) once you get that peanut butter cup all around spit it out and eat the other one in the package. You'll feel much better about the day.
 

seahaven

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I agree that putting plain poly resin over bare plywood is a hideously bad use. I used the example because plenty of people have seen (or had to redo) decks like this, and it highlighted one of the great strengths of epoxy resin. Poly resin alone is very brittle, epoxy resin is not. Polyester resin properly used with mat, cloth, and roving, or mixed with most fillers is fantastically versatile and strong. That was my whole point- both polyester and epoxy resins have their place in boat building and repair. You just play to the strengths of each.
 

Toolate

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Confirming the lifetime(s) of experience part... how the hell did you come upon this? Pretty funny actually. I dont want to be the tabman ever for the record.
 

Bill

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I think everyone needs to get their hands wet with epoxy.. its easier to use when you start off if you get the pumps that measures out the hardener perfectly.. its expensive but its hard as a rock.. you can mix the different fillers in and make a bunch of different fillets etc.. sand/grind them down and try it again.. thisis a good gateway into working with glass if you havent done any before.you are limited to what you can finish it with,, paint or 2 part only..

resin will drive you batty if you mix to much MEKP into it.. when i first started with my first few gallons or so I had more smoking resin in my driveway than anyone.. couldnt figure it out..then I tried the " teaspoon meathod and now I got a " squirt bottle" which is perfect..

I much prefer resin now but i would epoxy anything that really needed it as it will stick to anything.. if you ever buy epoxy dont use west system after you get used to working with it..go to aeromarineproducts.com.. its the same stuff, cheaper, easier mixing ratio

remember in the end its all just glue
 

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