Gelcoat void repairs -help- - SailNet Community
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post #1 of 6 Old 06-12-2009 Thread Starter
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Gelcoat void repairs -help-

Hi all,

So this week, at the suggestion of a friend, I rented a power-washer to remove the old flaky anti-foul coat. Doing so revealed what I believe to be gelcoat voids. There is absolutely no wetness, toxic / stinky fluids. I have revealed hundreds of them and fibers of what I believe to be the skin-up mat behind. I've decided to stop the power-washing for the moment, thinking perhaps I am causing more of a pain for myself than necessary…

I am curious of your thoughts on a couple of options:

Should I continue to power-wash and reveal all the “loose” voids and then repair? My thought here is to go ahead and get it over with.

Should I just scrape (by hand) the rest of the anti-foul coat off, sand, epoxy fill the current crop of voids, sand again, probably barrier coat (might as well, since there is some sort of void problem) and then anti-foul-coat, then sail.

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If you don’t mind looking closely at the last pic in the album, you will find “bubbles” that haven’t been removed. These are what makes me wonder if this is a sign that I should continue removing all the “bubbles” as some look to have hairline fractures on their edge that I wonder, if in time, will allow water inside, causing future damage. Or will a solid couple of coats of barrier (Interlux2000e) take care of it?

Finally, to those who have done epoxy filling under a boat -on a trailer- do you have recommendations as to how to make this process quick but effective? Don’t worry about the safety advice, I am very familiar with nasty chems and metals and take over-the-top precautions.

Thanks tons!

Last edited by BugsBunny; 06-13-2009 at 02:53 PM. Reason: Much better clarification in this version.
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post #2 of 6 Old 06-15-2009 Thread Starter
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decision so far...

I am leaning toward the rationale that continuing to powerwash will expose all the loose voids and, unfortunately, cause more work for me. My logic being "do it right one time instead of halfway 3 times". If they are popping out it's because it's their time to go.

My question now is practical: assuming I choose an appropriate epoxy (I can't remember what type is recommended on gelcoat, but I'll look again), how realistic is it to simply "spatula it on". Having never physically done this work is it really so simple? Simply squirt a bit on the affected area and then "Squeegee" it into the holes? I just want to know that (as I will be working against gravity under the boat) that the epoxy isn't going to just plop out of the holes once I fill them. Is the stuff so thick and pasty?

Do I really need to dremel them out first?

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Would it be better to get some syringes and squirt into holes; and then spatula; and then sand flush after cure? Or skip the syringe (sounds silly now that I ask)? I only ask because of the thought that air pockets could get trapped the voids as I spatula.

Thanks everyone for taking the time to help someone not so familiar with fiberglass repair...
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post #3 of 6 Old 06-15-2009
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Continue washing with the power washer. Apply one coat of epoxy with a roll, make sure it covers all the voids. Then apply epoxy with ground glass fiber to the voids with a spatula and apply a second layer of epoxy. If your hull is dry this will keep it dry from now on. If the hull is not dry (use a humidty meter.) Wash the hull with water and let it dry. This might take some time from a few weeks to two months. Apply the epoxy coatings after the boat is dry.
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post #4 of 6 Old 06-15-2009
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You need to fill the voids with Interlux Watertite or an epoxy paste such as West System epoxy mixed with colloidal silica. These adhere great and have the consistency of peanut butter and will not run or drip.

You need to do your filling first.

Your pictures show lots of little bumps which are voids-in-waiting. If you are going to repair this bottom you need to remove them also.

The right way to fix this bottom is to have a professional use a bottom peeling machine to remove the gelcoat and whatever underlying material have voids, following which someone (probably the pro) replaces same with new material, except your five coats of Interprotect substitues for the gelcoat. This type of fix is expensive...think $150-$200 per foot.

What you should do is just leave the bottom alone, repaint and enjoy the boat for a year or two. Then kick the problem down the road to the next owner. several regards...
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post #5 of 6 Old 06-15-2009
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Couldn't you pressure wash and then sand/grind to give the surface some "tooth" then wash down w/ sope and water , check for the proper moisture the a quick wipe w/ acetone , air dry and then start rolling or painting on the epoxy? I've seen this done. I haven't seen it come out after a year or two, but it looked decent.
I have a couple years experience using epoxy on different marine repair projects and it's important to note that you can get epoxy in different grades or thickness (vicosity ? ) I prefer the medium viscosity 50/50 variety as it makes mixing it alot simpler. I don't care for the west as it is difficult to get the mix correct. If you get it wrong it won't "go off" or get hard. and is a real treat to remove if this happens.
I bought 10 gallons a while back and use it on just about everything ! it is alot less obnoxious to work w/ and be around than polyester resin (fiberglass). And is 100% non permiable I believe. Although it doesn't like UV and needs to be covered/painted etc.
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post #6 of 6 Old 06-15-2009
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It depends on how much the boat is worth to you. If you like her and want to keep her, then invest in the bottom peel and sail worry free for the next 30years. If you don't want to spend a lot of money then just finish with the powerwashing and get everything opened up. Let it dry for a while then fill it and fair it with thickened epoxy and then give it 6 or 7 coats of unthickened medium viscosity stuff.

If you don't do anything the boat will get worse quite quickly.

Good luck.
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