Fibreglass Repairs

EZZ70

Well-Known Member
Hey,

If you own a fibreglass boat chances are sooner or later you will have to face a repair of some sort weather it be a chip, scratch, crack, delamination, hole in-fill or perhaps a full on restore project or projects much like I have done, which then, you will be faced with both cosmetic and structural challenges and decisions.

As I researched "what to do" and "when to do it" I have found many many conflicting opinions and methods, the biggest of all question was, What resin do I use? I have found that, like any topic, ppl will argue pro's and con's just for the sake of arguing, which can be frustrating to say the least. By reading thread after thread I just became more confused and doubtful that I could ever be confidant enough to get started on this massive undertaking, so as the days and weeks of research went on I decided to re-focus research specifically on successful individuals in the fibreglass business and what they had to say. Here is my findings...

TO GET SATRTED:

Q. Regardeless of the repair the question more often than not is, which type of resin do I use polyester, vinylester or epoxy?
A. The most "COMMON" repair will be made with polyester resin

With that being said, there is no "one resin fits all". each resin has its own properties and application for its intended use, several other factors must be considered such as, is it above or below water line, is it structural or cosmetic, what will be your finish material (paint or gelcoat or non), what materials (fibreglass cloth) will you be using and on what materials will it be applied/bonded to (existing polyester, vinylester or epoxy), just to mention a few determining factors for making your decision selection.

The advise that I received was, "not all resins are manufactured of equal quality" automotive differs from marine resin so when selecting a retailer please insure that it is one that has a high turnover of product because resin does have a recommended shelf life. Some resins have a longer shelf life than others but regardless, something to be aware of. You don't want to purchase expired resin as the chemical properties will have changed resulting in less than expected material performance or failure.

As the days and weeks go by I will try and keep adding to this topic in hopes that I can help individuals make the correct resin selection and/or at the very least provide me with another task, just what I needed! LOL

Thank you
Rob S
 
So if you're offering up the help I'll ask, for cosmetic holes (+-1/8") above the waterline in smooth visible areas what would your whole process involve? Could the filling be done to a point where someone else could do all the gel coat repairs after the fact? I'd like to fill a bunch of holes the previous idiot owner put around the boat adding junk solar lights and cheap rusted tool holders.

Hey Rain City, filling small holes from previous attachments is the most common repair, you don't need many tools or materials but are aesthetically satisfying when complete. :D

To answer your question, I would recommend, without having any fill material in the holes already, drill out the hole to the next biggest size thus removing any dirt and grim and exposing fresh material (wood/fibreglass) for the in-fill to bond to. If these holes are purely cosmetic go ahead and fill with a polyester based filler, try and squeeze/push as much as possible to fill the entire cavity to avoid bleed through or halo down the road. If the drilled hole goes all the way through to the other side I would place duct tape on the other side to create a stop for the filling material. After the hole/holes are filled and cured you can sand, I would suggest giving it a quick fairing to ensure all pin holes are filled then make paint ready, then apply gelcoat or paint. Make sure you clean the surface prior to applying the infill, gelcoat or paint with acetone or another cleaning agent to remove impurities that may affect final quality of finish....

Holes-2.jpg

I think I covered a bit of this process in one of my YouTube videos :) I used thickened epoxy as my filler as I will be painting and not gel coating.

Thank you
 
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Are you ordering your resins, epoxies, fairing compounds, and paint online? My town sucks for this stuff. I have two boats I'd like to do some work on.

Hey tubber, I purchased my materials primality from Industrial Paints and Plastic, I have also ordered from Jamestown Distributors... There are not many suppliers here in Red Deer and also challenging to get supplies, I have gone to CAPS, Central Alberta Paint Supplies, which is local, and purchased some supplies as well.

Post a few pics of the boats and lets see what you are thinking...? :)
 
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On the 1977 17' Whaler there are off-colour gelcoat patches, lots of fasteners and old holes that should be checked for strength and water proofness, needs new rub rail, there is tiny whaler water drip which I've attacked several times and patched with marine tex after drilling a hole and nothing comes out, and to top it off the whole boat was painted and it is flaking off, but the gelcoat beneath looks pretty good from what I can see. Mechanical and electrical are okay. Or I could use as is as per usual. She's never going back to pristine.

On the 1974 11'4" Whaler, just a few cosmetic things and I need to mount a different motor and the old holes don't match. Plus I'd like to figure out how to make it charge the battery for the electric motor and ff which the old one did and it does not.

Both trailers need a few things.

Fence and garden projects, and the pile of house things are standing in the way for now.
 
On the 1977 17' Whaler there are off-colour gelcoat patches, lots of fasteners and old holes that should be checked for strength and water proofness, needs new rub rail, there is tiny whaler water drip which I've attacked several times and patched with marine tex after drilling a hole and nothing comes out, and to top it off the whole boat was painted and it is flaking off, but the gelcoat beneath looks pretty good from what I can see. Mechanical and electrical are okay. Or I could use as is as per usual. She's never going back to pristine.

On the 1974 11'4" Whaler, just a few cosmetic things and I need to mount a different motor and the old holes don't match. Plus I'd like to figure out how to make it charge the battery for the electric motor and ff which the old one did and it does not.

Both trailers need a few things.

Fence and garden projects, and the pile of house things are standing in the way for now.

Hey, thank you for the background info, they sound like nice projects, not to complicated in nature but totally doable without major expense. Let me know if I can help you out and look forward to you getting the "to do" list completed!

Thank you
 
Tubber,Boston whaler boats are notorious for leaking and having saturated foam inside.They used very thin layups on the exterior hull because of the sandwich foam construction.Coast Guard used to buy new whalers and grind the bottoms and add a few more layers of glass so that they could beach them at lighthouses etc. ,believe it or not at the crazy Whaler new prices.You should be able to tell if saturated just by the weight of the hulls. The only fix is to separate the hull and deck and remove the saturated foam,not easy to do.
 
- Polyester resins or aka PE

Polyester resin, as mentioned is by far the most common resin in boat construction. This is due to cost and availability but mostly cost dependant.

Polyester resins are unsaturated synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Maleic Anhydride is a commonly used raw material with diacid functionality. Simply put, poly based resins are made from polyester solids dissolved in Styrene Monomer and activated with MEK (Methyl Ethyl Keytone) for curing.

Polyesters offer ease of handling, low cost, dimensional stability, as well as good mechanical, chemical-resistance and electrical properties. Polyester resins and, again, are the least expensive of the resin options, providing the most economical way to incorporate resin, filler and reinforcement.

You will find polyester the bases for both gelcoat and laminating resin although very different in usefulness and application. Simply, Gelcoat is the outer most surface of a fiberglass boat. Gelcoat has very little to no structural value and increases in brittleness the thicker its applied. The underlying laminates of resin-saturated glass fabric provide the structure and support required for integrity. The gelcoat's purpose is to protect the hull and provides its pigmented color and shine. AGAIN, gelcoat is NOT used for wetting out matting! Gelcoat is strictly cosmetic with some UV properties that protect the underlining material.

In addition, in order for polyester resin to fully cure it requires a sealant of sorts to be separated form the atmosphere. This is done in a few different ways, either by introducing wax (aka air dry) to the laminating resin at final layup or by the use of gelcoat. Please keep in mind because gelcoat is poly based as mentioned it to needs an additive to asset in its final cure so you can purchase gelcoat either waxed or non-waxed. Personally I purchase gelcoat and resin non-waxed and add styrene based wax at final.

If a mistake is made and waxed gelcoat is used you can easily remedy this by sanding the surface with sandpaper to remove the layer of wax, clean with acetone, then you are ready to reapply if need be. The same can be said for waxed polyester laminating resin. As long as the last coat of resin or gelcoat used was un-waxed you can apply over it within an appropriate amount of time.

The wax additive to styrene based solution allows for compatibility mixing in polyester based products. Once mixed and applied the wax floats to the top creating the barrier mention above, again allowing material beneath the wax to cure to a non tacky surface otherwise the material will stay kinda sticky.

Another way for poly based materials to cure would be the use of PVA (Poly Vinyl Alcohol). PVA serves the same purpose and principle as a waxed additive. Both PVA and Styrene Wax comes as a liquid and is usually measured approximately 2-3oz to one gallon of either gelcoat or resin based on humidity and temperature of your local. In contrast to wax (solute) and styrene (solvent), PVA's solvents evaporate leaving a layer of plastic which allows for all materials beneath to cure.

MEKP.jpg

Hope this is making sense, please like these posts if it is...

Thank you
Rob S
 
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There is a channel on YouTube called Boatworks Today. He has many, many video's on how to fiberglass. Check it out.

Yes, Andy is awesome, he is my go to guy. I subscribe to his Patreon channel as well... Andy uses allot of Jamestown products due to his local. He has helped me a great deal over FaceTime, I mentioned him in my earlier videos as a resource.

Andy has complimented on my work quality a few times now during the rebuilds, he has pretty high standards. :eek:

https://www.boatworkstoday.com
https://www.youtube.com/user/boatworkstoday
https://www.jamestowndistributors.com/userportal/main.do
 
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Tubber,Boston whaler boats are notorious for leaking and having saturated foam inside.They used very thin layups on the exterior hull because of the sandwich foam construction.Coast Guard used to buy new whalers and grind the bottoms and add a few more layers of glass so that they could beach them at lighthouses etc. ,believe it or not at the crazy Whaler new prices.You should be able to tell if saturated just by the weight of the hulls. The only fix is to separate the hull and deck and remove the saturated foam,not easy to do.

Mine is not saturated, but there is some moisture, like almost all Whalers of that vintage. I'm not really worried about it. No plans to take the deck off. Thickening the keel was one of my first repairs. Mine is a red dot hull, meaning slightly heavier layup. I'm prioritizing keeping more water out before trying to get any exiting moisture out.
 
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