Epoxy or Polyester as I replace large sections of Deck Core

[neilpride]

Definitely fix it by a Yada Yada man i can do it,, use or hire at your own discretion...

[smj]

Originally Posted by neilpride

Definitely fix it by a Yada Yada man i can do it,, use or hire at your own discretion...

Absolutely! That's why I wouldn't hire anyone that insists on using polyester for a structural repair.

[neilpride]

Definitely the material used for you repair It has nothing to do with it, i sugest you instead to condemn the resin used ,try to found a real Profesional...

[smj]

Originally Posted by neilpride

Definitely the material used for you repair It has nothing to do with it, i sugest you instead to condemn the resin used ,try to found a real Profesional...

I as a supposed Minaret qualified neophyte completed the repair successfully in epoxy where the professional botched the job in polyester. As I said, stick to your comfort level and I will stick to mine.

[neilpride]

Ok, to be clear, i stick to my comfort level obviously make more sense than your level, whatever horrible experience you have with your keel has nothing to do with the resin used, if Minaret choose epoxy or not is another history, now im just answering to your claim tht Poly for cosmetic work could be ok and structural nope, pure BS let me tell you, but please go ahead with your comfort level , after all is your boat..

[smj]

Originally Posted by neilpride

Ok, to be clear, i stick to my comfort level obviously make more sense than your level, whatever horrible experience you have with your keel has nothing to do with the resin used, if Minaret choose epoxy or not is another history, now im just answering to your claim tht Poly for cosmetic work could be ok and structural nope, pure BS let me tell you, but please go ahead with your comfort level , after all is your boat..

Your right, my boat which is built completely in epoxy resin so I have no choice. As I said, stick to polyester.....as least as long as the bond will allow[emoji16]

[neilpride]

So you have a epoxy boat and you hire a guy who do a repair spot in Poly, lol...who is wrong here , the Pro or the resin? Mr?

[smj]

If you would read my post I left the glass man a gallon of epoxy to do the repair on my previous polyester catamaran. The polyester didn't stick to the old polyester.

[neilpride]

I read your post well, still i dont see the resin used like a problem, most likely bad prep and bad practiques, if you stick Poly to a old poly hull is ok as far the prep is done right , if you use epoxy in a poly hull is ok to, if you use Epoxy on top a Poly hull is a no no, guess you have a bad experience from a poor job done in Poly, so far so good..

[smj]

Originally Posted by neilpride

I read your post well, still i dont see the resin used like a problem, most likely bad prep and bad practiques, if you stick Poly to a old poly hull is ok as far the prep is done right , if you use epoxy in a poly hull is ok to, if you use Epoxy on top a Poly hull is a no no, guess you have a bad experience from a poor job done in Poly, so far so good..

I have seem many failed poly to poly secondary bonds, not just the one on my old catamaran.

[lateral]

If your "comfort zone" has been built up from years of experience, run with it.
10:1 it will serve you well. Not much point shoving down some one elses throat.
Techniques differ...may be part of the equation.
Prep is everything.

[lateral]

My deck is Gelcoat in female mold, poly/ Tissue,3/4oz csm, peelplyed, one month wait then balsa/epoxy laminate over.
No significant difference in the peel test from epoxy to epoxy secondary to epoxy to poly secondary.
What we didn't compare was a Poly to Poly primary peel (chemical) because I was not completely comfortable with the glass to balsa interface with poly. Hence the switch.
I have complete confidence, above the water line, with poly on poly, below the waterline not so much. But, I probably would do it with a good epoxy barrier over.
My thinking is, as poly is more water vapour permeable than Epoxy, the poly/poly secondary bond interface is definitely at risk from water vapour. In a below the waterline situ.
MY2CW

[lateral]

Old Deck:
New Deck:

[neilpride]

Nice job, well done!!!!

[Souzag818]

Originally Posted by ramblinrod

So you encountered one instance of poor polyester adhesion despite there being millions of examples of excellent polyester adhesion on the water today.

And your conclusion is polyester doesn't adhere?

I recently cut deck core samples out of my boat. Dry, perfect adhesion, attempts to remove the laminate destroyed the balsa. Can't get better adhesion than that.

The boat is 42 years old.

No maintenance to the deck until her 40th birthday, when I sprayed fresh glecoat on her, because I could. Looks like new.

This is consistent with pretty much any decently built polyester FRP boat, that some fool hasn't allowed water to penetrate the core.

Have you seen a 40 year old cold moulded epoxy boat with zero UV maintenance? I have.

With my eyes wide open, every single one has been a disaster, rotting in a yard because it is not economically feasible to repair. Not 1%, not 10%; 100%.

So what does this tell an experienced FRP guy?

A) The elToro wasn't built properly, or someone allowed water intrusion into the core.

B) The UV protective finish on your dinghy hasn't failed yet. How often have you revarnished or painted?

Jeez, I didn't realize I had to provide numerous examples of poly delamination from a wood core. If I had known that I would have told you about my own Tartan that had major delamination on the cabin top and side deck, that was a factory layup which I repaired with okume ply and epoxy. Or the 37foot sail boat that I rebuilt over a two year period from the hull up with okume and sapele because, again, most of the decks and cabin top had delaminated from the ply core and begun to rot. Also a factory boat...Recently retired from the boat repair business after 35 years, so there are many more examples of poly resin NOT adhering to ply core, but I think I'd be wasting my time. As far as the dinghy, I've only painted it once with Awlgrip after I built it. It's faded and chaulky, but still protected and functional, so it doesn't matter to me. If you let an epoxy boat or repair get exposed to UV, it will break down. But that's called maintenance. All boats need maintenance, including polyester ones. Otherwise, you wouldn't have had to re-gel coat your decks. If you can't keep up with it you shouldn't own a boat. But now I'M just ramblin...