Whether you own one kayak or 100 at some point along the life of your kayak you might have to repair a crack or puncture. I have seen and tried plastic welding and first off I am not very good at it. I have gotten better over the years, but still not great. Secondly I feel the plastic welding is not a great option. If its a crack on the top side of the kayak, welding works wonderful. But if its a crack or tear around a scupper hole or somewhere else I am not completely convinced that plastic welding is the best repair. And so what we use at the shop is a modified kevlar skid plate kit patch.
So the first thing to do is determine where the kayak is leaking from. In most cases check around the scupper holes or the back 8 inches of the bottom of the kayak. These two areas usually see the most wear and tear.
Next you will want to cut out a piece of the kevlar material that fully covers the damaged area. In these photos we are repairing a kayak with a leaking scupper hole. I have found it best to just cut a large patch out and completely cover the hole. After cutting out the patch piece, place it in the boat and trace or dot around the patch leaving a 1/4 to 1/2 inch border from the patch itself.
Next take some masking tape and newspaper and tape off the area around the trace marks you made earlier. The epoxy tends to run and this step helps keep it in place as well as from getting everywhere.
At this point you are just about ready to start patching. You need to get a few things ready though. Go ahead and mix the hardener and resin and stir them well. Next grab a propane welder or hot air gun and very carefully flame the area you are going to patch. This causes the oil in the plastic to evaporate and is a must in this type of repair.
Now let the patch sit for 24 hours and the next day you can lightly sand off any rough edges. At this point you are done.
Few tips and suggestions. These kits can be bought off the internet. Northwest Canoe sells a great kit. Make sure you really rough up the kayak with the sandpaper and don’t forget to flame to area. The epoxy will not stick if you don’t flame the boat.
I have used this process for many years and it works great on just about all kayaks. Pelican kayaks are the exception. Nothing will stick very well to a Pelican, so if you damage one, toss it and go buy a decent kayak.
Hope this helps and if you have any questions, please feel free to call the shop.