poly vs. epoxy

[ry3100]

when i started my project everyone told me to use epoxy resin for it's waterproof properties. but i see people giving advise to use poly, which i have always heard is damaged by sunlight and isn't waterproof. i am putting in the floor now and have boght 5 gallons of epoxy (which isn't cheap!) could i have used epoxy and got a lasting result? Thanks for the input

 

[SS MAYFLOAT]

Re: poly vs. epoxy

By no means I'm an expert first of all. I have worked with some of the resins for a number of years now and this is based on my experience. <br /><br />My understanding on epoxy is that is is excellent for below waterline areas that are prone to being wet. Poly resin should always be painted or coated to seal it from moisture or UV's. Are you going to be covering your floor without painting/sealing it first, then epoxy would be good to use. Other wise if you used poly, all you had to do was put a coat or two of epoxy paint on it. That is how I do all inside boat repairs. Outside on the hull, I like using epoxy based resin.

 

[Realgun]

Re: poly vs. epoxy

There are a million threads on this subject I am going to refer everyone to SEARCH.<br />Thankyou.

 

[ry3100]

Re: poly vs. epoxy

boy i sure could have saved some money, maybe i'll ebay it and get poly to do the floor in. do you just paint it with any topside paint?

 

[ry3100]

Re: poly vs. epoxy

i did search admiral realgun, and i posted if you don't what to give input then don't

 

[bigbad 4cyl x2]

Re: poly vs. epoxy

i just did a whole floor,stringer ,transom project.with marine plywood and epoxy . im a beginer . but ive picked up two helpfull hints now that im done the first time #1 is to coat all the wood first before bonding to prevent out gassing. # 2 is to examine if i realy needed 1500$ worth of glue in my boat of 18 ft. i would like the epoxy and marine plywood for the transom . but would have gone with an epoxy mix to secure the stringers to the hull from there maybee went with poly for coating the ext grade plywood for stringers and floor . . i too feel strange spending this much for glue.

 

[ondarvr]

Re: poly vs. epoxy

Of the hundreds of boats being restored on this site how many of them started off with "the wood is in great shape, but the polyester resin and glass failed or rotted". None, well maybe somebody did, but what you read most of the time is that the transom or stringers looked good from the outside, but when I drilled or cut into them the wood was pulp. Poly does a pretty good job of holding a boat together even when the wood is mush, so how "bad" can it be. Poor quality wood and/or workmanship will cause the wood to rot, it makes no difference if it's epoxy or poly, if water gets to the wood it will rot.<br /> <br />Epoxy is great stuff, but poly rarely fails when even a marginally good job is done, so the extra money spent on epoxy is for the most part, in my opinion, overkill.

 

[Tail_Gunner]

Re: poly vs. epoxy

Nice post, clear concise and to the point.^

 

[Mark42]

Re: poly vs. epoxy

My next boat project will (most likely) be done in polyester resin. Just for the following reasons:<br /><br />1) It is in my budget.<br /><br />2) My 41 year old boat has a rock solid hull and it is made from poly resin. In fact, there is no place on the boat where resin has "failed" other than the gel coat from 40 years of UV exposure. <br /><br />So, until the price of epoxy comes down, Poly will have to do. Plus, poly has improved considerably over the years. So it's a better product now than what my boat was made from!

 

[epresutti]

Re: poly vs. epoxy

I have learned during my rebuild several things:<br /><br />Although epoxy is stronger than poly I would not use it for the following reasons.<br /><br />Much more expensive.<br />Harder to Wet out Glass.<br />Don't need the extra strength.<br />Can't sand it worth a darn if used as a fairing compound.<br />Cannot gel coat over the top and expect a good bond, must be painted.<br />Will not be able to use poly for any future repairs, will not bond properly.<br />Can do all the same with poly with (effectively) the same result for my purposes.<br /><br />Just my $.02<br /><br />Peace.<br /><br />Ed.

 

[Chinewalker]

Re: poly vs. epoxy

I am in the midst of removing the floor and transom from my third Starcraft restoration project. I find it amazing that the fiberglass peels up from the floor quite easily.. The transom glass came off easily, too, and in several areas was no longer attached even before I got to it. In my experience poly is fine for glass to glass repairs, but for wood to glass or wood to wood, go with epoxy...<br />- Scott

 

[ondarvr]

Re: poly vs. epoxy

CW<br /><br />You are correct, epoxy will bond to wood far better than poly does, but when done with at least some care, it will bond to wood adequately and even on boats that have poor poly to wood bonds the boat itself normally doesn't fail. You said it pulled off easily, but it hadn't in the life of the boat until you purposely pulled it off, which means it was up to the job of holding the boat together, it didn't fail in it's designed use.<br /><br />Epoxy is a much better product physically than poly, but when used to make or repair a small pleasure boat, it's difficult to take advantage of what it's capable of doing. <br />On a small repair the cost isn't a big factor, but as the size of the project increases, the cost for epoxy go's through the roof when compared to poly. For that extra cost, it really won't last any longer, be any lighter, look much different, or get you more hot chics.

 

[ry3100]

Re: poly vs. epoxy

well now i'm pissed i bought epoxy, however i did find it at a really good price of 40.00 a gallon with hardner which isn't that much more than poly!thanks for the input guys

 

[KRS]

Re: poly vs. epoxy

Originally posted by ry3100:<br /> ...could i have used epoxy and got a lasting result?

yes

 

[NBE]

Re: poly vs. epoxy

Man......you mean epoxy won't get me more hot chicks than poly will? Now you tell me!!<br /><br />

 

[Chinewalker]

Re: poly vs. epoxy

One thing to keep in mind. Most of us are paying MUCH more attention to detail than the assembly line workers who originally built these boats we're now rebuilding. We are taking better care to seal ALL edges, corners, surfaces, etc., working out more bubbles, grinding out more flaws, using better materials, etc. than they ever did 20-30 years ago. Whether it's poly or epoxy the end result will more than likely be BETTER than new! <br /><br />Bottom line is, use what you're comfortable with - there is no wrong answer to the question posed in the original post...<br /><br />- Scott

 

[ondarvr]

Re: poly vs. epoxy

That's probably the best response yet.

 

[Realgun]

Re: poly vs. epoxy

I used epoxy cause the smell of Poly makes me a bit sick.<br /><br />And I will stick by my SEARCH recomendation.

 

[Realgun]

Re: poly vs. epoxy

Oh and if I were to use POLY I would go with the vinylester type.

 

[crab bait]

Re: poly vs. epoxy

epoxy is a glue.. poly us not.. <br /><br />epoxy is a mite flexiable.. poly is not.. <br /><br />epoxy is waterproof ( keeps rot causing water molecues from passing thru ) .. poly does not..<br /><br />epoxy cost more.. poly does not..<br /><br />you get what you pay for..