I have no immediate access to Aramid (Kevlar) tape or cloth. Nor do I need it in minimum quantities being offered online. I do have plenty of e-glass tape, mat and cloth and G-Flex.
I want to patch a 2 inch thin (but through) hull crack near the apex of the “V” shaped keel inside a CD Kestrel 140 aft storage compartment.
Am I going to regret using e-glass for a standard practice 3 layer patch repair to a Current Designs hybrid hull material?
There is nothing wrong with E fiberglass. Fiberglass fibers are actually much stronger in compression than aramid fibers of the same thickness and they incorporate in resin better.
S fiberglass is roughly 20% stronger than E 'glass but you can make up for that by adding an extra layer of E 'glass if you are concerned about it. S 'glass also has somewhat better abrasion resistance but that should not be a factor in your repair if you can do it from the interior of the hull. If you have to patch the hull from the exterior, fiberglass would be preferable to aramid.
Fiberglass is really pretty amazing stuff with an excellent balance of strength in tension, strength in compression, and bond strength to vinylester and epoxy resins. The only real advantage aramid has over it is a higher strength to weight ratio in tensile strength only. Since you are probably not going to be applying that much weight in terms of fabric, the difference in weight would be trivial.
Thank you for answering, pblanc. Your excellent advice is always appreciated. It is an inside patch - so I’ll proceed with what I already have on-hand.
I couldn’t pass up the opportunity to purchase this Kestrel 140. It was spoken for - but then the purchaser ‘passed’ on it.
It has everything I have been looking for in my first kayak.
The good thing about glass is that you can feather the edges and make it smooth. Aramid doesn’t sand well.
If you can find a piece of Nida Core, you could put it on the inside and glass over it. It will strengthen the area. If not, be careful, that section will be a little weaker than the areas around it.
You can easily feather the edges of Kevlar (aramid) patches using a carbide scraper, which also works really well for shaping and feathering fiberglass.