Gelcoat can be successfully applied over Epoxy repairs

[smj]

Originally Posted by neilpride

Insurance companys most of the time ask for OEM materials in the repairs, i see lots of holed boats , broken, from the last canes passing the islands , all this boats repaired using Poly and gel and not a single failure, to bad to paint a stern extension when the boat have gel on topsides , if you can match a gel extension with the surrounding gel this is the best aproach in my opinion,, tabbing is another history and i see lots of broken joints but honestly Ply and poly ,and the prep is not always good.



No one is saying epoxy is weaker , but if you can make a repair or upgrade using the same material much better.

Read post #17, clearly stated a poly to poly repair was stronger. And thank you for agreeing that epoxy is stronger.


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[rognvald]

So, for small repairs(stress cracks, cosmetic gouges, etc.,) with West System Epoxy/fillers on an original gelcoat surface, only painting the repairs will give a reliable bond?

[Exile]

Originally Posted by HappyMdRSailor

Let's see... $12.8M-materials/$13.73hr (happy's lam labor rate)...
****licks thumb****
**pulls life expectancy actuarial tables**
"oh dear"
Uhm...

My compensation as an amateur doing amateurish work thus far would have to be closer to $1/hr. given how long it takes me to try and get this sorta stuff done. And let's not assume that $1 would necessarily be incoming. But at least my goals are modest, i.e. "do no harm." So the good news on my various & sundry deck dings is that the deck is now much better sealed.

The bad news is that the sealing was done with a combo of West Systems epoxy (some now gel'd over, others just ugly brown spots), and gel & cabosil that is poorly color-matched. Ironically, it turns out the base gel I bought rather closely matches the smooth parts of my white decks, but please don't even ask how long (and how much wasted gel) it took me to figure that one out. As for the grey-tinted nonskid areas, let's just say it's a work in progress. I can safely say that at least my varnishing skills are improving, but not to the point where Neil or Minaret would ever want to hire me.

As usual, I learned a few things on this thread -- thanks. And glad to hear SMJ's extensions worked out for him.

[HappyMdRSailor]

Originally Posted by Exile

My compensation as an amateur doing amateurish work thus far would have to be closer to $1/hr. given how long it takes me to try and get this sorta stuff done. And let's not assume that $1 would necessarily be incoming. But at least my goals are modest, i.e. "do no harm." So the good news on my various & sundry deck dings is that the deck is now much better sealed.

The bad news is that the sealing was done with a combo of West Systems epoxy (some now gel'd over, others just ugly brown spots), and gel & cabosil that is poorly color-matched. Ironically, it turns out the base gel I bought rather closely matches the smooth parts of my white decks, but please don't even ask how long (and how much wasted gel) it took me to figure that one out. As for the grey-tinted nonskid areas, let's just say it's a work in progress. I can safely say that at least my varnishing skills are improving, but not to the point where Neil or Minaret would ever want to hire me.

As usual, I learned a few things on this thread -- thanks. And glad to hear SMJ's extensions worked out for him.

Seems like we could have some pretty good compensation being paid to STAY OUT of the shop space of Neil and Min !

And I think we'd be able to pick out SMJ's boat in a crowded marina quite easily...

[Southern Star]

HappyMD, you could probaby pick out SMJ's previous boat because it was thoughtfully improved and well-maintained. As I recall, the epoxy hull extensions were painted with a matching color to the gelcoat, but separated by a stripe to account for the different qualities of the finish and dissimilar fading. In fact, even gelcoat that matches color at the time of application will typically, over time, fade differently from the original, older gelcoat. In the result, either finish would likely require a stripe to overcome the visual contrast of the hull extensions that would appear over time.

While I have no doubt that experienced professionals such as Minaret have the knowledge and ability to create a good bond between new and old polyester, I wonder if the same is true for most amateurs? Certainly, various studes have shown that epoxy bonds better to old polyester..... In any event, while I have never undertaken anything as extensive as hull extensions (although I seriously contemplated it a few years ago), when I had custom made brackets for a fuel boss system bonded to the inside of my hulls in the engine compartments, it was done with epoxy resin. Was that wrong?

Brad

[smj]

Originally Posted by HappyMdRSailor

Seems like we could have some pretty good compensation being paid to STAY OUT of the shop space of Neil and Min !



And I think we'd be able to pick out SMJ's boat in a crowded marina quite easily...

Pretty much what Brad said above, we painted a graphic of a star where the paint met the gelcoat, you would have to look really hard to tell it was added on.
Let's face it, there is a tremendous force put on the 4' stern extensions that we added to our cat. Epoxy is known to have far superior qualities over poly when it comes to secondary bonds, and the bond joining the 4' stern extension was a secondary bond on 20 year old poly. I personally think it was a prudent decision going with the more expensive but superior epoxy over poly where there would be such stresses.
Our second Seawind 1000 came with stern extensions already done by the previous owner. There was a pretty good sized crack, about 14" long where the stern extensions were bonded into the original hull. My guess would be they were done in poly, but it was repaired in epoxy.
And you are right, picking out our old Seawind in a crowded Marina would have been very easy. She was a well kept cat with beautiful lines in my opinion.



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[Hamish_ct]

I'm not a pro but I do a lot of gel coat repairs. All my sons sail competatively. which means a lot of bumping and dad can you fix that.

From experience and what I have read. Gel coat will chemically adhere to polyester resin. It will stick to epoxy resin but after 2 yrs you will be doing the job again. The gelcoat will flake off. I've seen these videos but they are not accurate. Not sure what they are selling and from experience I will keep to what the pros and the builders use.

If you want to add strength to the polyester resin mix in fiberglass strands.

[minaret]

Pretty sure adding a huge graphic on the blend line so you can't tell the finish doesn't match isn't an option much of the time. Do you do this on deck too?


Done many an extension on 100' plus power boats. I assure you the loads on the 4' extension on your cat don't compare. Have yet to see one done in epoxy.


Have also done many structural mods on large commercial fishing craft; extensions, sponsons, spray rails, fish holds, etc. These see far harder use than any yacht. All poly secondary bonds, zero failures. Never seen any commercial work done in epoxy. Except for timber boats.

[clockwork orange]

Originally Posted by minaret

Pretty sure adding a huge graphic on the blend line so you can't tell the finish doesn't match isn't an option much of the time. Do you do this on deck too?


Done many an extension on 100' plus power boats. I assure you the loads on the 4' extension on your cat don't compare. Have yet to see one done in epoxy.


Have also done many structural mods on large commercial fishing craft; extensions, sponsons, spray rails, fish holds, etc. These see far harder use than any yacht. All poly secondary bonds, zero failures. Never seen any commercial work done in epoxy. Except for timber boats.

Minaret, You are banging your head against the wall mate. Amateurs who have been subjected to the constant ads and articles in retail magazines telling them how much superior epoxy is and how all repairs should be done using it and teaching them how to consume as much of it as possible while on the PE and VE side there has always been silence. I have never in over 40 years in the trade seen an ad for polyester in a retail sailing magazine. So, absent the ability to do their own thinking they take it all as gospel. There is no convincing them but meanwhile the vast majority of boats are still being built and repaired with PE and VE by those who know more than just what they read.

[smj]

Originally Posted by minaret

Pretty sure adding a huge graphic on the blend line so you can't tell the finish doesn't match isn't an option much of the time. Do you do this on deck too?


Done many an extension on 100' plus power boats. I assure you the loads on the 4' extension on your cat don't compare. Have yet to see one done in epoxy.


Have also done many structural mods on large commercial fishing craft; extensions, sponsons, spray rails, fish holds, etc. These see far harder use than any yacht. All poly secondary bonds, zero failures. Never seen any commercial work done in epoxy. Except for timber boats.

I appreciate your concern over the cosmetics of my boat. It's obvious your business in the marine industry is more involved in cosmetics than structure. If you can't admit that epoxy is a superior product for secondary bonds to a polyester hull I would suggest a refresher course in boatbuilding. Had a good laugh over our debate with a 70 year old friend of mine that has been in the marine industry and boat building business for over 50 years. Maybe polyester never reaches a full cure in the PNW? Anyways, it really doesn't matter as you will do things as you feel fit as will I and as long as you and your customers are happy that's all that matters.


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[neilpride]

Originally Posted by smj

I appreciate your concern over the cosmetics of my boat. It's obvious your business in the marine industry is more involved in cosmetics than structure. If you can't admit that epoxy is a superior product for secondary bonds to a polyester hull I would suggest a refresher course in boatbuilding. Had a good laugh over our debate with a 70 year old friend of mine that has been in the marine industry and boat building business for over 50 years. Maybe polyester never reaches a full cure in the PNW? Anyways, it really doesn't matter as you will do things as you feel fit as will I and as long as you and your customers are happy that's all that matters.


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Cosmetics? Minaret? hehehe LoL. Nahh go ahead and click search Minaret threads and see if they are pure cosmetic, then come back with your results..
What he say is common sense , i see the same stuff , a graphic hiding the blending edge ,, but oh well your boat not mine, up to you.. I dont have any problem with epoxy at all, in fact i work with epoxy to, its superior in bonding caract and its stronger ? yes... Gelcoat stick well to cured Epoxy? Nooo. Can you save lots of cash using Poly instead of epoxy ? Yes.. Can you have a strong repair usin Poly or built whatever part in Poly ? It happen everyday ....

[HappyMdRSailor]

Originally Posted by Southern Star

HappyMD, you could probaby pick out SMJ's previous boat because it was thoughtfully improved and well-maintained. As I recall, the epoxy hull extensions were painted with a matching color to the gelcoat, but separated by a stripe to account for the different qualities of the finish and dissimilar fading. In fact, even gelcoat that matches color at the time of application will typically, over time, fade differently from the original, older gelcoat. In the result, either finish would likely require a stripe to overcome the visual contrast of the hull extensions that would appear over time.

If it's the boat I'm thinking of, I've seen the documented work... I recall it was a nice job... And yes... different gel will fade differently... I suggest a little refresher on blending...

BUT.... This thread was all about applying GEL OVER EPOXY... which was never an option with the material used...

While I have no doubt that experienced professionals such as Minaret have the knowledge and ability to create a good bond between new and old polyester, I wonder if the same is true for most amateurs? Certainly, various studes have shown that epoxy bonds better to old polyester..... In any event, while I have never undertaken anything as extensive as hull extensions (although I seriously contemplated it a few years ago), when I had custom made brackets for a fuel boss system bonded to the inside of my hulls in the engine compartments, it was done with epoxy resin. Was that wrong?

Again... Nobody is debating the strength and bonding properties of epoxy... If a job could use either poly or epoxy, I go with epoxy 80% of the time...

And ANY AMATEUR can do proper prep for a poly bond...

And.. And... Your choice of epoxy for your fuel boss install was perfect.... EXCEPT... if you were planning on spraying pretty gel over it...

Brad

Originally Posted by smj

Pretty much what Brad said above, we painted a graphic of a star where the paint met the gelcoat, you would have to look really hard to tell it was added on.
Let's face it, there is a tremendous force put on the 4' stern extensions that we added to our cat. Epoxy is known to have far superior qualities over poly when it comes to secondary bonds, and the bond joining the 4' stern extension was a secondary bond on 20 year old poly. I personally think it was a prudent decision going with the more expensive but superior epoxy over poly where there would be such stresses.
Our second Seawind 1000 came with stern extensions already done by the previous owner. There was a pretty good sized crack, about 14" long where the stern extensions were bonded into the original hull. My guess would be they were done in poly, but it was repaired in epoxy.
And you are right, picking out our old Seawind in a crowded Marina would have been very easy. She was a well kept cat with beautiful lines in my opinion.

If your main reason for choosing epoxy over poly was simply for the bond strength to the previous poly.... Then I suggest that the design and layup schedule of the extensions could have been vastly improved...

And YES... I think she's a very pretty cat!

Originally Posted by clockwork orange

Minaret, You are banging your head against the wall mate. Amateurs who have been subjected to the constant ads and articles in retail magazines telling them how much superior epoxy is and how all repairs should be done using it and teaching them how to consume as much of it as possible while on the PE and VE side there has always been silence. I have never in over 40 years in the trade seen an ad for polyester in a retail sailing magazine. So, absent the ability to do their own thinking they take it all as gospel. There is no convincing them but meanwhile the vast majority of boats are still being built and repaired with PE and VE by those who know more than just what they read.

+1

Originally Posted by neilpride

Cosmetics? Minaret? hehehe LoL. Nahh go ahead and click search Minaret threads and see if they are pure cosmetic, then come back with your results..
What he say is common sense , i see the same stuff , a graphic hiding the blending edge ,, but oh well your boat not mine, up to you.. I dont have any problem with epoxy at all, in fact i work with epoxy to, its superior in bonding caract and its stronger ? yes... Gelcoat stick well to cured Epoxy? Nooo. Can you save lots of cash using Poly instead of epoxy ? Yes.. Can you have a strong repair usin Poly or built whatever part in Poly ? It happen everyday ....

+1

[smj]

Happy, the design and layup of the extensions has absolutely nothing to do with how they are attached to the old polyester hull.


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[HappyMdRSailor]

Originally Posted by smj

Happy, the design and layup of the extensions has absolutely nothing to do with how they are attached to the old polyester hull.


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OK

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[SF Bay Dude]

Failure will occur. I just had to grind down my whole deck because of a flub at the factory. They used gelcoat over an epoxy primer. #fail