How is your polyester resin holding up over the years?

[Mark42]

For those of you who have made repairs using polyester resin, I would like to hear how well it held up over time. Especially coating the deck with just resin and no glass. I've read a lot on this forum that resin alone will not last on a plywood deck. I tend to agree that the resin will perform much better with some CSM or cloth in it.

The reason I am asking is the 1965 MFG Niagara I have has some plywood that is only coated with resin (that's 1965 resin, not as refined as the stuff we have now) and it has not cracked, checked, peeled or failed in any way. That's 44 years of use, abuse and neglect and the resin is still as sound as the day it was installed.

I am curious how well resin only decks and resin/glass decks and any other parts have been holding up in your boat.

 

[halas]

Re: How is your polyester resin holding up over the years?

I am glad that someone asked this question since there is a lot of poopooing going on about the cheaper resin but no one I've seen gave any data of actual personal experience.
I have used it as gluvit for a 14' Mirrocraft's aluminum boat rivets. I also glassed a removable 1/2" pressure treated plywood floor for the same boat. I figured that I should experiment with a small boat where there is not much lost if the material failed. It has been a few months only but I will report if any bad news comes up. I also used poly resin for gluing the transom halves together and for glassing the non treated plywood transom in the same boat.
So far it is doing very well.

 

[rucaradio]

Re: How is your polyester resin holding up over the years?

I'm in the same boat (no pun intended). I've got a 19' cabin cruiser in need of some new stringers, a whole new transom, and a new floor.. Although I'd love to go the epoxy route, I just can't justify nearly $1,000 to do the whole thing - especially when you can buy fur gallons of poly for every one gallon of epoxy. I think the trick is to PREP like crazy - make sure everything is sanded with 35 grit, sweep up after yourself, and clean it with acetone.

 

[jonesg]

Re: How is your polyester resin holding up over the years?

The structure beneath the deck plays a large role, if the deck flexes a fair amount the poly alone will crack.

If the wood was dried properly before installation thats a big help too.

My freind the builder says PT ply shrinks for 6 months, thats why he doesn't paint it until its aged a bit.

My take on it is this, it doesn't HURT to glass.

 

[halas]

Re: How is your polyester resin holding up over the years?

Mark said: "The reason I am asking is the 1965 MFG Niagara I have has some plywood that is only coated with resin (that's 1965 resin, not as refined as the stuff we have now) and it has not cracked, checked, peeled or failed in any way. That's 44 years of use, abuse and neglect and the resin is still as sound as the day it was installed."

Mark,
That 1965 resin is epoxy? Was polyester resin used back in 1965.
I am really ignorant about the whole resin thing.

 

[ondarvr]

Re: How is your polyester resin holding up over the years?

It has great deal to do with the type of wood used in the plywood, some types hold up very well even without a coating, others types of wood can start to check (crack) in a short period of time and will cause even epoxy to fail. You might want to take a closer look to see if there's a layer of very light cloth in the coating, light cloth can be very hard to spot if done well.

 

[Mark42]

Re: How is your polyester resin holding up over the years?

.....Mark,
That 1965 resin is epoxy? Was polyester resin used back in 1965.
I am really ignorant about the whole resin thing.

It is polyester resin. Don't think they had epoxy back then. Even today, the vast majority of boats are built with polyester resin. Epoxy is generally only used by home boat builders and high tech racing machines.

ondarvr, its just coated, no cloth. I've had to drill holes there to mount stuff and although the poly chipped off then, it still holds up otherwise.

 

[proshadetree]

Re: How is your polyester resin holding up over the years?

My dad put the floor of a 75 sidewinder back in 15 years ago.The cover rotted off the boat so it sat in the sun rain and snow for 12 years.I can see no spots on the floor but it has only had junk thrown in and been pulled around for all that time never got to put drive back in before gell went south.Jumped up and down on it last year.No movement.It has no stringers.Its a jet boat.About 3.5 ft wide of regular old plywood.I was cheap in my 20s.He put it down with walmart polly.

 

[Mark42]

Re: How is your polyester resin holding up over the years?

Ttt