How to repair this gel coat damage

b_arrington

b_arrington

Well-Known Member
GOLD Sponsor
Feb 21, 2007
3,479
Setauket, NY
Boat Info
Back Cove 37
AB Ventus 9VL
Engines
Cummins QSC 8.3 600
Last fall we had a major wind storm that caused my boat to yaw in the slip and the swim platform rubbed up against the dock. It cause the damage in the photo below. It obviously wore through the gel coat and rubbed away some of the fiberglass as well. What's the proper way to repair this?

I have a supply of color matched gelcoat that came with the boat. Do I just prep the surface and build up the gelcoat? Do I need to apply some new fiberglass and epoxy first? There's no structural damage evident; just the cosmetic damage.

As an enhancement I'm going to install some rub rail in the spring. It should cover the entire area but I don't want to leave that raw fiberglass.

upload_2020-2-24_12-58-20.png
 
Maybe. Grind it up/clean it out. Add a little resin to sand smooth. Then patch with gel coat.
 
If you're definitely going to add the rubrail (even a slip-on, vinyl style would work easily/well) and it will cover the area, you can actually skip doing the gelcoat all together if you want. Just paint the raw fiberglass with some poly or epoxy resin - a couple quick coats is all it needs. It will totally protected after that. If you want, a little white paint (or tint the resin) will help it blend in if some of it will show.

But, for the gelcoat - sand the area (including some of the existing white gelcoat) so everything is nice and fresh, then apply your gelcoat - ending up slightly higher than the surrounding area so you can sand smooth. But, you don't the gelcoat to be too thick - although you'll probably be fine in this case. Otherwise, build up the low spots with some resin, first. If you've worked with Bondo on cars, it's the same idea - except that the gelcoat is also the final product.
 
Lazy Daze said:
If you're definitely going to add the rubrail (even a slip-on, vinyl style would work easily/well) and it will cover the area, you can actually skip doing the gelcoat all together if you want. Just paint the raw fiberglass with some poly or epoxy resin - a couple quick coats is all it needs. It will totally protected after that. If you want, a little white paint (or tint the resin) will help it blend in if some of it will show.

But, for the gelcoat - sand the area (including some of the existing white gelcoat) so everything is nice and fresh, then apply your gelcoat - ending up slightly higher than the surrounding area so you can sand smooth. But, you don't the gelcoat to be too thick - although you'll probably be fine in this case. Otherwise, build up the low spots with some resin, first. If you've worked with Bondo on cars, it's the same idea - except that the gelcoat is also the final product.
Click to expand...

Thanks. I've done a bit of gelcoat work, mainly filling in nick and gouges. None were this deep but its not my first go-around. I have two types of gelcoat that came with my boat: a pure-white brushable type, and a hull-color matched "regular" type. I suppose I could use some of the brushable to build up a little then apply the color matched type? Doing a little research suggests that gelcoat doesn't like to be applied over epoxy resin and poly resin would be needed.

As far as the rub rail, this is 100% on my to-do list this spring. I just need to get measurements so I can place the order. I'm going to use Tessilmare Bino 40 2-piece rub rail. It's 1 5/8", so I think it will completely cover the damage. There might be a little that could show on the bottom, hence why I could want to effect a repair. It might not have to look pretty if the rail covers it; I have to get a measurement to confirm.

This is the rub rail I selected. The whole shebang should be under $150.

BINO40_G.jpg
 
Epoxy vs gelcoat... Actually, that is more of myth than truth. Or, at least, maybe it USED to be true with older formulations of epoxy or gelcoat. Heck, I always thought it was true, too. But nowadays, gelcoat sticks just as well to epoxy as it does polyester. I saw a REALLY good test done a number of years ago to disprove the myth. Since, I've tried it a few times with excellent results. Just an FYI.

Sounds like you're good to go with the methods. One suggestion on the rubrail... consider one that wraps down and over(under) the bottom edge - sort of like where the bottom edge of the rubrail has an "L" shape to it. That way the bottom edge of the fiberglass is also protected. Try Taco Marine for some ideas - although if you've been looking at rubrails, you probably already know about them.
 
Lazy Daze said:
Epoxy vs gelcoat... Actually, that is more of myth than truth. Or, at least, maybe it USED to be true with older formulations of epoxy or gelcoat. Heck, I always thought it was true, too. But nowadays, gelcoat sticks just as well to epoxy as it does polyester. I saw a REALLY good test done a number of years ago to disprove the myth. Since, I've tried it a few times with excellent results. Just an FYI.

Sounds like you're good to go with the methods. One suggestion on the rubrail... consider one that wraps down and over(under) the bottom edge - sort of like where the bottom edge of the rubrail has an "L" shape to it. That way the bottom edge of the fiberglass is also protected. Try Taco Marine for some ideas - although if you've been looking at rubrails, you probably already know about them.
Click to expand...

Yep I looked at Taco, good suggestion. I didn't see a profile that I particularly liked. The methods in which most of their rails are sold were a little difficult for this project. Taco rails seemed to be sold in lengths of 50 or 65 feet. I need about 20 feet, and the Tessilmare product line is pretty much all sold by the foot that's a good match. I like the extra cushion of the Bino rails as well. It also seems to install very easily.

I just looked up West Systems Epoxy project guide. They indicate that gelcoat goes over their epoxy so that's extra confirmation of your experience. I have some West epoxy in the garage so I'm good to go.

Thanks for the advice!
 
b_arrington said:
I just looked up West Systems Epoxy project guide. They indicate that gelcoat goes over their epoxy so that's extra confirmation of your experience. I have some West epoxy in the garage so I'm good to go.
Click to expand...
You know why? 'Cause the person that did all of that testing I was referring to worked hand in hand with West Systems - well, basically, he reached out to them to supply the product and because they knew of him and his accomplishments in the social media world, they sent him the product to use.

Looking for some good videos to watch? Andy Miller owns a glass repair shop in Wisconsin. I don't know him personally, but he sure seems like a really nice, down to Earth kind of guy. His media webpage is boatworkstoday.com. You can find his video links there and/or search on his website for "gelocat epoxy" and you'll find the videos I mentioned earlier.

If you start watching his videos... be forewarned... you will need a big pot of coffee to watch all of his videos. Not because they are boring or uninteresting - far from it - but because you WILL binge watch ALL of them!!! They're addicting!
 
Lazy Daze said:
You know why? 'Cause the person that did all of that testing I was referring to worked hand in hand with West Systems - well, basically, he reached out to them to supply the product and because they knew of him and his accomplishments in the social media world, they sent him the product to use.

Looking for some good videos to watch? Andy Miller owns a glass repair shop in Wisconsin. I don't know him personally, but he sure seems like a really nice, down to Earth kind of guy. His media webpage is boatworkstoday.com. You can find his video links there and/or search on his website for "gelocat epoxy" and you'll find the videos I mentioned earlier.

If you start watching his videos... be forewarned... you will need a big pot of coffee to watch all of his videos. Not because they are boring or uninteresting - far from it - but because you WILL binge watch ALL of them!!! They're addicting!
Click to expand...

Oh yeah, I burned an hour plus last week watching him. Rabbit hole city right there, in a good way.
 
+1 for Andy. I try to watch his Sunday drops each week. Makes it easier than devoting hours to a binge watching.

-Kevin
 
If you can't find a 'wrap under' rub rail maybe try attaching it slightly low so it sticks just a little lower than the bottom edge? Not really enough to be noticeable but enough to protect it?

Sounds like you have your plan of action but another option might be Spectrum Gelcoat paste. I bought some for our 1986 250DA for a few spots and will be ordering some soon for some touchup on our Crownline. It's color matched paste to touch up small gouges or scrapes. Just apply it then sand and buff when you are done.
 
boatman37 said:
If you can't find a 'wrap under' rub rail maybe try attaching it slightly low so it sticks just a little lower than the bottom edge? Not really enough to be noticeable but enough to protect it?

Sounds like you have your plan of action but another option might be Spectrum Gelcoat paste. I bought some for our 1986 250DA for a few spots and will be ordering some soon for some touchup on our Crownline. It's color matched paste to touch up small gouges or scrapes. Just apply it then sand and buff when you are done.
Click to expand...

I’ve used the Spectrum stuff in the past and it’s been good. Luckily I won’t need it this time. As part of the standard equipment, Back Cove provides a quart of every color gelcoat used on the boat. So I have a quart each of flag blue, grey stone (for my non-skid), White for the decks, and brushable white for the bilges. It’s a great thing to have and not worry about matching.
 
IMG_4230.JPG
The damage to your swim platform is the sort that can be easily repaired by spraying new gel coat over the damaged area and featheriing the thickness beyond the damage. Properly done, the repair will be invisible. This is a very forgiving location so it would be a good place to learn how to do this type of work if you are handy.
 
sbw1 said:
View attachment 80227 The damage to your swim platform is the sort that can be easily repaired by spraying new gel coat over the damaged area and featheriing the thickness beyond the damage. Properly done, the repair will be invisible. This is a very forgiving location so it would be a good place to learn how to do this type of work if you are handy.
Click to expand...

Thanks. I am pretty handy. I repaired a bunch of dings in the Amberjack, and also a number of voids in her hull that appeared after the bottom was blasted. If I may say so, they turned out darn nice. I also repaired some cracks in the bottom of my RIB last year. It's not my first time working with gelcoat but I haven't had an issue that was down to the glass before so wanted a little guidance. I think I'll not spray it though; if for no other reason that cleaning a sprayer always seems to take 5x longer than the actual spraying. And it's a small area.

As always, the folks here are some of the most helpful around.
 
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