20/12/2023
Got an old, faded JKK kayak? We're not bagging them, many of them are excellent boats and still doing the job for you just nicely, so we're not saying to take it to the dump. BUT, we do get a lot of damaged ones through the workshop for repairs and upgrades so we need to manage expectations of what can be done to help you maintain it's lifespan.
Kevlar (the yellow fiber) is amazing stuff - almost untearable, which is why it's used in bulletproof vests... and kayaks. In the fabrics in this video it is interwoven with carbon (the black fiber) for increased stiffness. However, Kevlar degrades quickly in UV light and becomes brittle, losing it's strength which is an inherent problem for old JKK kayaks because they do not have a protective coating such as gelcoat. We recently installed a WatchMount into a "slightly" faded Total Eclipse and Rikki was curious to see how the strength of the cutout section compared to a cutout section from a Nautique kayak. The weights of the materials in the two samples are very similar, so it's a good comparison.
Firstly, the video shows the difference in colour of the Kevlar fiber between the two cutouts - you can see the faded-brownishness of the old JKK sample compared with the fresh, bright yellow of the Nautique sample (it will stay this way because it's protected from the UV by the gelcoat). Secondly, you'll see that the cutout from the Nautique kayak, when bent with the carbon/kevlar hybrid material on the outside of the radius (the way it's designed to bend around rocks etc) does not break. Admittedly, Rikki is no Hercules but, all the same, he simply cannot break it because the Kevlar won't tear. Thirdly, you'll see that despite his physical inadequacies Rikki can quite easily break the JKK sample, bending it in the same direction. The deteriorated Kevlar fiber tears quite easily and carbon is no help for this type of function.
So.... what does that mean for our repair-shop customers? If your old JKK kayak is faded and you want to give it a spruce-up, there are two option. The cheap and cheerful option is to give it a lick of epoxy resin which will return some of the gloss and make it look fresh again. However, this achieves nothing in the long term because the new epoxy will quickly fade and meanwhile the real problem of the degrading kevlar is still happening, with nothing to protect it from the UV. The second option is to apply a new, clear, UV protective coating which will slow down further degradation and also return the gloss to the kayak. This is pretty spendy but if your JKK kayak is not too degraded or damaged, could be worthwhile.
