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Approach to Small Bow Damage

Saltydog87

New Member
New/old Sunfish found to have a small crack near the bow - I suspect someone ran into a pier. The area overall feels solid, but it’s the bow, so I was thinking...
1. Feather out from the cracks to create a void into virgin material past the crack ends.
2. Fill in this void with 1708 glass and a laminating resin to reinforce the area
3. Polyester repair putty if needed to fill any remaining low spots...?
4. Top with waxed gelcoat for seal/cure
5. Sand/buff

Is this overkill? I was worried that trying to just fill it with polyester putty wouldn’t have enough strength for this part of the boat.
Worth the effort to try to colormatch the gelcoat of the hull, or just gelcoat the whole hull to keep things simpler? There are a couple other very minor dings typical of an old/used Sunfish I’m thinking to fill in while I’m at it.
 

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L&VW

Well-Known Member
My philosophy has been to make the area stronger than "before". (I also always use epoxy). What you propose isn't "overkill".

So, I'd cut out the damaged area--plus a margin for internal fractures I can't see.

Pull a cardboard or modeling plywood "backer" against the hole, and build up layers of cloth and mat. As you proceed,, remove the trapped bubbles with roller or Flux brush "pokes". I use a slow catalyst, so I'm not rushed.

Finish as you see fit. Members here say gelcoating is tricky business, so I use paint. (Rustoleum).
 

Saltydog87

New Member
I was debating resin vs epoxy, because I understand that epoxy and CAM matting or 1708 don’t mix, due to the binding agent. I’ve also been reading that epoxy can be stronger than resin though and possibly more waterproof? Anyone have tips of pros/cons for each?
The dent is not a hole - it’s still very solid, so I’m confident I can sand a bevel down so I can fill across the crack and build it back up.
 

Saltydog87

New Member
Is gelcoat a waste of time/effort on a used boat (ie not coming out of a mold)? Cost-wise, it appears similar to paint. Color matching seems more complex if I need to do that (or shell out for precolored gelcoat from a company like fibreglast). It has sounded like it should be more durable though...?
 

L&VW

Well-Known Member
As the lake is a fresh water resource for drinking water, the lake where I sail frowns on anti-fouling paints—which are designed for saltwater applications.

Capsized, I'd want to display white or orange bottom paint around the lake's high speed powerboats.

I was debating resin vs epoxy, because I understand that epoxy and CAM matting or 1708 don’t mix, due to the binding agent. I’ve also been reading that epoxy can be stronger than resin though and possibly more waterproof? Anyone have tips of pros/cons for each?
The dent is not a hole - it’s still very solid, so I’m confident I can sand a bevel down so I can fill across the crack and build it back up.
While it's strictly not a hole, IMO, a leak-test will show bubbles. Some tufts of the factory roving material are showing. It can be patched as you describe, but it will still be a weak point—where weak points pull the boat towards the edges of a dock. :oops:

It still amazes me how thin the Sunfish hull surfaces are! Seen from inside, the hull roving appears like a waffle. The thickest part is probably close to 5/32nds of an inch. The thin part, including the gelcoat, is closer to 1/8th. (Maybe—even less).

The weave in the below Sunfish hull photo shows about 1/4-inch-wide glass strands, with relatively large spaces between warp and woof.

Fullscreen capture 642017 70619 PM.bmp-001.jpg
 

shorefun

Active Member
Go at it with a sander and expose the area. See what the damage is.

After a lot of poking around the web and finally talking to a couple of people I feel are knowledgeable I have come to the conclusion there are many ways to properly fix the glass. With the sunfish it is not very thick and just about anything will work.

I believe it is not worth the expense for epoxy. Just use a quality resin. Get some matt and some cloth at the light end. You do not need much. If you were near me I would give you what you need.

Sand back good and use the 80 grit to make for better holding.

You may or may not need to take out the glass that is there and put a backer in place. You need to grind the surface off to see. It is pretty easy to do. The wide roving on the inside of the of the hull will not likely give you the best adhesion for great structure, my guess at least. But you will need a backer for the patch.

I find gel coat does fine on top.


In the end this is only a sunfish and does not have a lot of stress on these areas. I say keep it simple, make sure you have everything sanded properly for best adhesion and it seems just about anything works. Personally I have a problem with paints like Rustoleum working in the water long term, but I have no experience. I do know it is soft compared to gel coat.

Finally I will say I do not have a ton of experience with glasswork so take my advice with a that in mind. I will add I am a hands on kind of person with experience with building antique car patch panels from scratch. I have done some research on how glues bond and kind of understand the mechanics involved.
 

Saltydog87

New Member
As the lake is a fresh water resource for drinking water, the lake where I sail frowns on anti-fouling paints—which are designed for saltwater applications.

Capsized, I'd want to display white or orange bottom paint around the lake's high speed powerboats.


While it's strictly not a hole, IMO, a leak-test will show bubbles. Some tufts of the factory roving material are showing. It can be patched as you describe, but it will still be a weak point—where weak points pull the boat towards the edges of a dock. :oops:

It still amazes me how thin the Sunfish hull surfaces are! Seen from inside, the hull roving appears like a waffle. The thickest part is probably close to 5/32nds of an inch. The thin part, including the gelcoat, is closer to 1/8th. (Maybe—even less).

The weave in the below Sunfish hull photo shows about 1/4-inch-wide glass strands, with relatively large spaces between warp and woof.

View attachment 44872
Thanks for the great tips and input! I totally agree about the anti fouling paint - and it doesn’t make sense for a boat not stored on the ocean - but it so far has been the only bottom paint I could find besides gelcoat. Am I missing something?

I was worried about those tufts being what you described, which is why I checked for it to be a soft spot and was surprised that it had absolutely no give. I believe there is a block at this area of the hull to support the bow handle. So perhaps that is what is backing/supporting it? Not sure how I would get more backing up that far, but it has a bow access port put in so I’ll try to take a peak.

Are 1708 and laminating resin not going to provide enough repair strength?
 

L&VW

Well-Known Member
My last use of polyester resin was in 1962, and 1708 wasn't even a dream back then. :rolleyes:

About 15 years ago, I bought a gallon of expensive West epoxy locally, and had paid about $70. I'm still using it satisfactorily, but transferred the contents to glass jars when the West gallon container developed a slow leak.

The bow handle backing-block is tiny, as is the space available to bolt it on. :cool:

The tufts shown are supported by the other side of the fracture. Because of the "compound curve" in the hull, that part is going to be hard to press back in.

When the gelcoat is sanded away, it should be easier to push the tufted side back into alignment. Sand a little more, and a less aggressive repair can be completed using polyester components.

Even Bondo has entered the marine putty market! :eek:
 
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