Stress cracks on bottom of kayak - best way to repair?

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Darkarcher159
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Stress cracks on bottom of kayak - best way to repair?

Post by Darkarcher159 »

On my last trip to Matagorda I developed a leak (a bad leak!!) in my Native Manta Ray kayak. Upon inspection I found 2 stress cracks (one about 1 1/2 half inches long and the other about 2 inches long) both are right next to the scupper holes in the middle of the kayak under the seat. I was thinking about fiberglassing the cracks to add strength, but for what I have been reading fiberglass and plastic don't mix. I was thinking just welding plastic would not be strong enough to keep the cracks from forming again.

Any ideas on how to fix these cracks?
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kickingback
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by kickingback »

First check your warranty and do contact the maker to ask if they have a particular warranty for that area having issues. You may get it repaired for free.
If no go on free, then YouTube is your friend. Lots of "welding" vids on fixing kayaks.
Good luck!
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Darkarcher159
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by Darkarcher159 »

I got the kayak used and I checked the website of the manufacturer and no such luck. I am afraid that the "plastic welding" I have seen on youtube will not keep the cracks from forming again. Long run I am getting a new kayak, but I need this one to last a little bit longer. Just looking for ideas.
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Neumie
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by Neumie »

What model year is the kayak?

I've heard of other manta rays developing cracks at the scuppers in the seat pan in the past. First thing I would do is drill stop the cracks to prevent them from getting longer. Plastic welding around scuppers is tricky. If you attempt it you can get some pieces of plastic from the inside lips of hatches so the color matches. Since there's access behind the seat I would silicone in closed cell foam blocks under the seat pan for support, too.
TG05
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by TG05 »

As suggested, drill a hole at the end of each crack to prevent further cracking. Slather in 3M Marine Sealant 5200 to fill the cracks. It's a polyurethane polymer so it adheres to plastic well, stays flexible and watertight, and is designed to form a permanent bond or seal below the waterline. It's used on through-hull fittings.
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kickingback
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by kickingback »

Darkarcher159 wrote:I got the kayak used and I checked the website of the manufacturer and no such luck. I am afraid that the "plastic welding" I have seen on youtube will not keep the cracks from forming again. Long run I am getting a new kayak, but I need this one to last a little bit longer. Just looking for ideas.
There are videos on people using wire mesh to weld over the cracks to give it more support. Look around YouTube. Do a thorough search with words that may be used to weld plastic of different kinds.
imaoldmanyoungsalt
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by imaoldmanyoungsalt »

I welded my Heritage redfish around the scupper holes in the seat pan and they are holding really well.
kayak weld 2.jpg
kayak weld 1.jpg
I used this from Lowes to weld it
https://www.lowes.com/pd/Weller-Electri ... it/3402984

and plastic from a lowes bucket
https://www.lowes.com/pd/Encore-Plastic ... et/3083565
imaoldmanyoungsalt
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by imaoldmanyoungsalt »

and as Neumie said, make sure to drill holes at the ends of the cracks so they don't get any longer
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by imaoldmanyoungsalt »

and I said seat pan but they are actually in the foot well near the seat pan
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Chubs
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by Chubs »

How is your redfish blue? Lol.
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Re: Stress cracks on bottom of kayak - best way to repair?

Post by yakattak_jake »

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Re: Stress cracks on bottom of kayak - best way to repair?

Post by yakattak_jake »

TG05 wrote:As suggested, drill a hole at the end of each crack to prevent further cracking. Slather in 3M Marine Sealant 5200 to fill the cracks. It's a polyurethane polymer so it adheres to plastic well, stays flexible and watertight, and is designed to form a permanent bond or seal below the waterline. It's used on through-hull fittings.
Yeah that’s a good to-do also to prevent the cracks from forming again. I’ve had to do the same thing on my KC on the top half.


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