Hello, 
the cockpit of my Nelo racing kayak has broken off. I've attached some pictures. 

It needs to be quite strong as I pull myself up holding on to the broken part when getting out.

The appearance is not important.

What is the best way to fix this?

Thank you in advance, Jurgen

From the look of the original material it looks like a simple 2/2 twill around 200g so i would get something like this: Carbon Fibre 2/2 Twill 3k 200g 1m Wide You would also need a resin such as our XCR Epoxy Coating Resin  to laminate the repair.

You need to repair on both sides ideally. to build up some extra strength.  Sand out all the loose broken bits and give the area a good key.  Build up patches on one side and then  the other ensuring a good overlap with good material so that the repair is nice and strong.  You can change the patch size as you build up the repair to try and feather the edge in a bit smoother.  Also once done, a nice thick coating of the XCR can then be applied to smooth out the surface.  Once cured, the XCR can be sanded and smoothed to tidy up the overall appearance.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Hello,

I have finished the repair now but after the boat has been in the water for the first time the surface all went white. Please see picture.
Why did this happen? and how can I improve the surface appearance?

Thanks a lot, Jurgen

Doesn't look like you've attached a picture, but it sounds like the resin wasn't properly cured before being exposed to water. How many hours after laminating did you leave it before taking it into the water? 

+x

 

Hanaldo - 3/10/2018 11:36:06 PM

Doesn't look like you've attached a picture, but it sounds like the resin wasn't properly cured before being exposed to water. How many hours after laminating did you leave it before taking it into the water? 

Hello Hanaldo,

there should be a picture now showing the white areas (my repair) and the black areas of the original boat.
You might be right. We left it about 48 hours but it was quite cold so it might not have been enough.
Is it a case of rubbing down and applying another layer of XCR, or is it better to get some sort of top coat?
Thanks a lot for your help.

Yeh that would be it then, even once epoxy has gone hard, it is still susceptible to water ingress until it is actually fully cured. Generally I would tell people not to expose anything to water or chemicals before at least 72 hours at 25 degrees, so if it was colder than that then it certainly would have been a bit vulnerable. If you can, get it under a bit of heat for a day or so; this will ensure the resin is fully cured and may even help some of the water damage. A set of 500w halogen work lamps, or just a space heater will do the trick.

You can try rubbing it back and seeing how far the moisture has gone into the epoxy, if you can remove it just with sanding then you can just polish it back up again - I would recommend doing this dry! It does look like it is fairly affected though, so you may have to remove quite a lot of it, in which case you will probably need a new layer.

Agreed with the above. Epoxy needs a fair bit of time to fully cure at ambient temps. I've seen epoxy go milky like this and almost recover with heat and time.

As said above, way too soon for exposure to water, especially this time of year.  Although initially hard within 24-48hours, epoxies remain hydroscopic throughout the main cure which can be 7 days or more depending on ambient temperature, post cure etc.

In your case, try and get the boat somewhere as warm as possible to see if it is still green enough to drive out the moisture with warmth.  You might be lucky and get rid the whiteness that way.  Otherwise you will need to sand away the bad resin and add fresh.

Also bear in mind that you can get similar issues with poorly mixed  resins too as it won't fully cure  and remain vulnerable to moisture, so it is key to keep close eye you measuring and mixing accuracy.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant