How to reshape a bent kayak nose??

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bignoseplant
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How to reshape a bent kayak nose??

Post by bignoseplant »

Hello guys,

I went for a swim today and my boat (and bum) suffered the consequence.

Does anyone know how to reshape a bent kayak nose? Of have any advice?

Cheers in advance guys!!
Chris

no9ismine
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Re: How to reshape a bent kayak nose??

Post by no9ismine »

Never had to try it but had a few people tell me hot water poured into the nose whilst the boat's vertical and the plastic will 'pop' back into shape. That's assuming it's not split - will need welding if that's the case.

Oh and invest in some bow airbags if you didn't have them already

bignoseplant
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Re: How to reshape a bent kayak nose??

Post by bignoseplant »

Thanks for the response. I'll give it a try. There are no cracks or creases.

I'll let you know how it goes.

MikeVeal
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Re: How to reshape a bent kayak nose??

Post by MikeVeal »

I'm not convinced that boiling water helps.
Have tried it to get the oil canning out of a boat and it didn't work.

When welding boats with a digital temperature controlled hot air gun, I've observed that the plastic doesn't soften until 240C and melts between 280C and 320C (two different boats).

So boiling water at 100C isn't anywhere near hot enough to soften the plastic, and certainly isn't hot enough to convince those thermoset plastic molecules to accept their new form.

I have never tried to get a nose dent out, but this is how I'd try.

Personally I'd apply a Black and Decker hot air gun to the area. Move it around a lot until the whole area appears shiny. Heat the area up slowly as you want to soften the plastic all the way through, not just the surface. Going slowly will also help avoid over doing it, you really don't want that.

When it's warm it needs to be gently pushed out from the inside. Depends on the dent how you go about it. Maybe stuff the end with rags and use a long pokey thing to apply pressure.

That said, if it's above the water line, is it really worth bothering with?

Oh, small disclaimer, will not work with cross linked poly boats.

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Xan
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Re: How to reshape a bent kayak nose??

Post by Xan »

Hot water works. Used it a few times. Hang it from a tree from handle/broach loops and poor in lots of boiling water. Make sure you use remove foorplate and step out pillar. Ones the boat is warm enough use a brush handle or bit of wood to prise it out. Last time i did it with our club boat had to fill boat leave it, empty, then refill. The cold plastic meant water cooled too much the first time

Garry
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Re: How to reshape a bent kayak nose??

Post by Garry »

Depends how bad the damage is but have also used the hot water and broom handle approach outlined above to good effect with dents in the nose. would advise EXTREME caution before using the hot air gun approach though as they are very fierce heat if used on plastic and if you dont know what you are doing you could easily do more damage than you already have, whereas with the hot water approach you are unlikely to make it worse.

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Jim
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Re: How to reshape a bent kayak nose??

Post by Jim »

Hot water works well on dents, it allows the plastic to return close to it's original set position (I never even needed to use a broom handle on my spud) to relieve the internal stresses that have been applied. Best done sooner rather than later.

It has little or no effect on oil canning though (even on the spud) because the deflection from the original position is so small and there is little internal stress as a result. I got most of the oil canning (from long term storage in the conservatory) out by using a wide flame on my blowtorch, same basic technique I used to squash the stern all those years ago.

If you have to use a blowtorch or heat gun take extreme care if you also need to use something to push the boat back to shape, you can easily end up with broom handle shaped indentations as the plastic stretches when pushed - this has never been a problem for me using boiling water with PE, but I have had it when using boiling water with royalex because the ABS softens at a lower temperature than PE.

Compare the vicat softening and heat deflection temperatures of ABS and HDPE in this link (there is no definiteve melting temperature which is more relevant to welding):
http://www.toolcraft.co.uk/vacuum-formi ... pp-pvc.htm

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Adrian Cooper
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Re: How to reshape a bent kayak nose??

Post by Adrian Cooper »

Please, people, be very cautious about Mike's advice. If you need to "convince those thermoset plastic molecules to accept their new form" then, sure or especially when welding. But usually you are trying to get the boat to return itself to its original form and the last thing you want is to get the plastic 'shiney' from the heat.

MikeVeal
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Re: How to reshape a bent kayak nose??

Post by MikeVeal »

Looks like I'm in the minority!

But I certainly agree with Adrian, you have to be very careful with a hot air gun.
He's also right about my spelling. :(

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Adrian Cooper
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Re: How to reshape a bent kayak nose??

Post by Adrian Cooper »

Sorry Mike, I hadn't spotted the spelling error. Indeed, I had to go back to look for it. :-)

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Oat
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Re: How to reshape a bent kayak nose??

Post by Oat »

Tip for the future.... Kayak noses usually get stowed in as when waterlogged that will be the deepest / lowest part of the kayak (assuming you have air bags in the rear). Put a cheap lightweight football or other similar buoyancy behind your full plate footrest and in future that will help it sit higher in the water rather than hit and dig in rocks.

dpround
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Re: How to reshape a bent kayak nose??

Post by dpround »

I have fixed a dent in a plastic kayak by leaving it in the summer sun - might be a bit tricky at the moment though! I should think boiling water would be plenty hot enough to do the same.

All the best

David

Ian5
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Re: How to reshape a bent kayak nose??

Post by Ian5 »

I have removed several significant dents using the hot water method described.

I would say use lots of boiling water and be patient, it takes time but gets there in the end.

If you see white lines marks its permanently damaged I think.

Good luck.

bignoseplant
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Re: How to reshape a bent kayak nose??

Post by bignoseplant »

Thank you all for the responses.

I have it somewhere near the original shape. I tried the boiling water trick and it didn't seem to work on its own. I ended up hanging my boat, and leaving it in front of a halogen heater for a while.

I wasn't too sure about a heat gun, if you had seen my "decorating" you would know why.

Thanks again guys!!

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