Epoxy / Polyester Resins Question

[ramblinrod]

Originally Posted by NevisDog

No one in their right mind would repair "a hole in the hull" using poly!

Why not?

[ramblinrod]

Originally Posted by smj

So if I understand this correctly, a very well prepped hole in the boat or stern extension done by a good fiberglass professional in polyester can give results that are satisfactory. I'm guessing the only way you will find out if the prep was good enough or the fiberglass man was a true polyester wizard is if you stress the boat enough and she comes out unscathed. Now if for some reason the prep wasn't good enough or the glass guy wasn't a wizard you'll find out when the patch peels of the hull or the extension falls of, usually when the boat is being put through some serious stress? If it were my house or possibly a house boat on a benign lake I may take the chance as the results wouldn't be as catastrophic as this happening in the middle of the ocean. I do believe I will shell out a few more $'s for epoxy and feel better about my chances. This is coming from a guy who had a pro glass man do a patch on our keel that was hanging on by a thread the next time we hauled.

What were the qualifications of the pro?

Did you really hire a "pro" or a "schmo"?

If you shopped for lowest cost without checking qualifications or
references, prolly the latter.

[DeepFrz]

Originally Posted by ramblinrod

One can do all kinds of things. But poly doesn't always play nicely over epoxy.

I remember one cold night, hours before a hard launch date, running out of
Watertite epoxy fairing a hull / keel join. With no other option, I mixed up
some poly and filler. Nope, didn't play nice. I ended up scraping all of that mess off, and redoing completely in poly. Finished just as the sun was coming up. Kicked myself for even starting with the watertite. Ate the 6 hours of prime billable hours it cost me.

And you accuse me of using straw man arguments.

For a busy man you sure spend a lot of time defending your views.

[ramblinrod]

Originally Posted by smj

So if I understand this correctly, a very well prepped hole in the boat or stern extension done by a good fiberglass professional in polyester can give results that are satisfactory. I'm guessing the only way you will find out if the prep was good enough or the fiberglass man was a true polyester wizard is if you stress the boat enough and she comes out unscathed. Now if for some reason the prep wasn't good enough or the glass guy wasn't a wizard you'll find out when the patch peels of the hull or the extension falls of, usually when the boat is being put through some serious stress? If it were my house or possibly a house boat on a benign lake I may take the chance as the results wouldn't be as catastrophic as this happening in the middle of the ocean. I do believe I will shell out a few more $'s for epoxy and feel better about my chances. This is coming from a guy who had a pro glass man do a patch on our keel that was hanging on by a thread the next time we hauled.

Nope, you don't understand correctly. Sound repairs with poly doesn't require
Magic or special expertise. Just the same sound prep and application methods as one would do with epoxy.

The proof in the pudding is the same. How is the test for effective epoxy repair any different than the test for effective poly repair?

[lateral]

Originally Posted by DeepFrz

And you accuse me of using straw man arguments.

For a busy man you sure spend a lot of time defending your views.

And some time "ramblin"....

[minaret]

It is, as usual, painful but entertaining (in a bad way, like the Trump administration) to watch a bunch of amateurs on the internet berate a professional who is trying to help them on matters of which they know little but think they know much.

[minaret]

Originally Posted by ramblinrod

Why not?

Many polyester boats were/are built in two halves, joined together with poly, right down the middle. If it can hold 2 halves of a boat together, certainly it can hold a hole patch of any size.

Now watch all of these people carefully ignore this question and refuse to answer it. These are the same people who appear to believe that poly production boats are all built in a single 24 hour period, therefore within the bond window for poly! Fact is, every poly boat out there is chock full of major secondary structural bonds, usually including a centerline seam glassing the two halves of the hull together, as you say. This is a secondary bond every single time, yet I've never seen a poly boat split down the middle. And usually they only glass the seam on the inside!


People who've built or fixed a boat or two and think they are pro's entertain me, they get so upset about the Holy Epoxy and it's supposed superiority in all things. It's funny! If they wanna waste the $$ and effort using epoxy where it's not called for, let them. Meanwhile I'll continue quietly helping the sane ones make OEM repairs in the half the time with half the materials cost, when they come to ask about it.


Good luck fellow Poly warrior, but if you look you'll find you haven't made a single argument I haven't made on this forum before, including this one. With the same people spouting the same nonsense in response.

[minaret]

Originally Posted by neilpride

Why not, here in the island is a regular job , hundreds of boats repaired in Poly and doing fine, even after years, if you can make a multi stern extensión in poly you can patch a big hole in poly, usually do it by Pro´s.

Hi Neil!

I know you guys do lots of multi extensions, but what about all the power boat extensions out there? I've done many on boats up to 120'. With that much displacement involved and under way at speed the loads involved are astronomical. Never done one in anything but poly, never seen one done in anything but poly. Currently repairing a 76' Hatteras which started life as a 68' Hatteras. It burned and sank in 100' water (engine room fire, boat scuttled to douse flames after six hours fire fighting). The extension is the least damaged part of the vessel, and the bond is fully intact after some time sitting on a rocky bottom at depth with substantial currents.

[lateral]

I'll tip my hat to you minaret but the RR is ramblin on the spontaneous combustion of epoxy in the presence of nothing combustible.
If I could have had a fire I would have...plenty of smokers.
Hatricks blew the kettle roof off cooking poly.
Somewhat irrelevant to subject.

Concurr on the efficacy of poly though, I've laid down a few thousand liters of it. And its adhesive qualities are underated.
Calling yourself a boat building professional doesn't necessary mean you don't make the odd F/U... like mixing epoxy filler powder with poly by mistake or forgetting to catalyize.

People have to be comfortable with there decisions.

[minaret]

Originally Posted by lateral

I'll tip my hat to you minaret but the RR is ramblin on the spontaneous combustion of epoxy in the presence of nothing combustible.
If I could have had a fire I would have...plenty of smokers.
Hatricks blew the kettle roof off cooking poly.
Somewhat irrelevant to subject.

Concurr on the efficacy of poly though, I've laid down a few thousand liters of it. And its adhesive qualities are underated.
Calling yourself a boat building professional doesn't necessary mean you don't make the odd F/U... like mixing epoxy filler powder with poly by mistake or forgetting to catalyize.

People have to be comfortable with there decisions.

Indeed they do, but it's arguments like those being presented here that cause people to be uncomfortable with something they should not be uncomfortable with.


For the record, never seen either poly or epoxy spontaneously combust, though I've melted many a pot, seen lots of cracking and smoking, even seen actual combustion in core material (ply) due to extreme exotherm. But no actual ignition. However, I'm not splitting hairs as I know exactly what RR means. It's clear to me he is a real industry pro of some standing in his area. You guys shouldn't bust his chops so bad, try paying attention to the general message instead of picking one single little thing he said you don't agree with and picking on it.

Also for the record, no such thing as "epoxy filler powder". All of the fillers I'm familiar with can be used with any resin system and often are. And poly resin changes color when you catalyze it, if you "forget to catalyze" on my crew you are out. Only takes one of these, because if you do this you've just proved you are either totally color blind or a moron. someone else on the crew would spot this and stop it immediately before applying if a rank amateur did such a thing, because it's visible.

[lateral]

Originally Posted by minaret

Indeed they do, but it's arguments like those being presented here that cause people to be uncomfortable with something they should not be uncomfortable with.

Also for the record, no such thing as "epoxy filler powder". All of the fillers I'm familiar with can be used with any resin system and often are. And poly resin changes color when you catalyze it, if you "forget to catalyze" on my crew you are out. Only takes one of these, because if you do this you've just proved you are either totally color blind or a moron. someone else on the crew would spot this and stop it immediately before applying if a rank amateur did such a thing, because it's visible.

Well, if you regard sticking to manufacturers specs read on a bag of 410.
Try mixing west 410 with Poly you can end up with a goop that wont cure. Colin at ATI said it was owing to the styrene dissolving the powder inhibiting the free radical process, the combination taking the O off the MEKP. You can get away with over catalysizing. As said,its on the west bag. Never tried it again as its in black and white. Also beige ain't the colour of PU. (White)
411 works and is more the colour of PU, as its silica based.

WARNING! Do not mix with polyester or vinylester resins. 410 Microlight mixed with WEST SYSTEM may be used over cured and properly prepared polyester and vinylester surfaces.

When you are mixing minute brews for repairs of CLEAR polyester it aint that hard. Didn't happen often. Never sacked any of my crew for it, but then ramifications weren't there as the job was small.
Our resin also didn't have the colour change additive so prominent, came out the kettle sooner, much clearer........thats showing my age.
Although, for my industry the finished laminate had to be completely clear, even with fins at 10mm thick. It did lose the accelerator colour slightly but if you waited for that you would not get the laps down and with half a doz repeat processes happening one after another it was inevitable at some stage.

[lateral]

If you only think its a ploy to get people to buy more epoxy....have at it. I will stick to the mineral fillers with poly.

[ramblinrod]

Originally Posted by lateral

I'll tip my hat to you minaret but the RR is ramblin on the spontaneous combustion of epoxy in the presence of nothing combustible.
If I could have had a fire I would have...plenty of smokers.
Hatricks blew the kettle roof off cooking poly.
Somewhat irrelevant to subject.

Concurr on the efficacy of poly though, I've laid down a few thousand liters of it. And its adhesive qualities are underated.
Calling yourself a boat building professional doesn't necessary mean you don't make the odd F/U... like mixing epoxy filler powder with poly by mistake or forgetting to catalyize.

People have to be comfortable with there decisions.

You are taking the "spontaneous combustion" comment more literally than intended.

When curing, properly mixed epoxy can get hotter than a witches T%$Y and start smoking. It can get far too hot to handle.

If it is near something combustible it can ignite it (like an internet acquaintances boat that burned to the ground in a yard when he left a pot of epoxy curing inside).

Mix a batch of epoxy properly and let it kick in a plastic cup filled to the top on a hot day.

Hint: Keep it away from combustibles or you will see a first hand example of spontaneous combustion.

Meanwhile poly, mixed properly, under the same conditions, doesn't get nearly so hot. (Though one can over-catalyze and do the same.)

[minaret]

Originally Posted by lateral

Well, if you regard sticking to manufacturers specs read on a bag of 410.
Try mixing west 410 with Poly you can end up with a goop that wont cure. Colin at ATI said it was owing to the styrene dissolving the powder inhibiting the free radical process, the combination taking the O off the MEKP. You can get away with over catalysizing. As said,its on the west bag. Never tried it again as its in black and white. Also beige ain't the colour of PU. (White)
411 works and is more the colour of PU, as its silica based.

WARNING! Do not mix with polyester or vinylester resins. 410 Microlight mixed with WEST SYSTEM may be used over cured and properly prepared polyester and vinylester surfaces.

When you are mixing minute brews for repairs of CLEAR polyester it aint that hard. Didn't happen often. Never sacked any of my crew for it, but then ramifications weren't there as the job was small.
Our resin also didn't have the colour change additive so prominent, came out the kettle sooner, much clearer........thats showing my age.
Although, for my industry the finished laminate had to be completely clear, even with fins at 10mm thick. It did lose the accelerator colour slightly but if you waited for that you would not get the laps down and with half a doz repeat processes happening one after another it was inevitable at some stage.

Yeah, that could be the one exception to the rule. I never ever use 410 with anything as I've seen it fail far too often. You gotta stop focusing on the one exception to the rule, you can't see the forest for the trees like that.


There is no color change additive, poly resin simply gets darker after catalyzing. It always has. Anyone with any experience can tell the difference between catalyzed and uncatalyzed at a glance.


Where I'm from if we want clear resin we go to a clear casting resin with a special catalyst. Most outfits also use catalyst with red dye in it for regular laminating (many come this way), but I hate that stuff. For the aforementioned reasons, it's redundant.

[smj]

Originally Posted by minaret

It is, as usual, painful but entertaining (in a bad way, like the Trump administration) to watch a bunch of amateurs on the internet berate a professional who is trying to help them on matters of which they know little but think they know much.

As usual, if someone doesn't agree with you they are amateurs, yet the man that calls polyester secondary bonds as strong or stronger than original you call a professional. Laughable.