I was wondering how to fix a crack in the rear of my tarpon 120 the back wore out from dragging it and it now has a crack and some reinforcment needs to be done do you know of any way to fix this problem?
We have found JB weld actually works well on the keels of poly boats as well. Also in a pinch on Mothership trips ive used MarineTex and Splashzone Epoxy.
Most of the time however I will do a weld for customers and also build up the area while I am at it. It just takes a little practice and you will achieve good looking welds. All you need is a Benzomatic torch or heat gun and you can weld these boats just fine. You dont need any special equipment such as a welder. Actually most welders will not work because they are designed for Metal use and a Gas Welder burns too hot and will quickly rob the Polyethylene of its oils causing it to dry out and become brittle.
in the field repair: Gutter Repair tape. available at Home Depot or Lowes. It's a thick aluminum foil bonded to a thick black tar that REALLY sticks to the plastic. You need to get 'er dry and warm BUT the repair really works on cracks and such. Paint thinners takes off the tar once you scrape off the foil for a decent repair.
The welders I'm talking about are NOT metal welding units but welders made specifically for plastic. we use 'em at the plant where Confluence boats are made. In R/D we have to weld tons of things on prototype boats. The welders are a heating unit hooked to compressed air. The airflow can be adjusted and plastic welding rod feeds into the unit and you can lay down a sweeeet bead. we weld cockpit rims and hatches on boats and even have to weld scupper holes on SOT prototypes. I'll get the brand name of one of the models. Think they run about a grand!
If DIY'ers weld use heat w/o flame. The flame will 'burn' the plastic, causing impurities and a bad weld. A heatgun or soldering iron will work.
Ahh the Plastic Welder. The phrase Welder being directed to people on the board might be confusing for other as It was for me. Thanks for clearing that up Steve. Plastic Welders are definitely not cheap.
I use a Torch when i weld to Preheat the plastic to a pliable form however the final amounts of heat used in the weld are applied with a Heat gun and Soldering Iron to avoid the scorching/ Burns caused by flame. Works very well for me.
I would like to echo what Pamlico 140 typed. I have tried welding on my own, and it went poorly. I have paid someone to do it, and each time it held and outlasted my ownership of the kayak.
As far as dragging, I advocate it, but not by lifting the front grab handle and starting off. This wears on one spot, making for short work of creating a hole. I drag using the strap I wrote about in the recently posted article. Separating the kayak from yourself with a 6 to 8 foot rope spreads the wear out over the entire hull as opposed to concentrating it on one spot. I've worn through under a seat where most of the abuse of scraping over a mostly exposed ledge rock occurs. I believe that the holes I wore in the two kayaks were a result of fishing Mid Atlantic rivers during drought periods and NOT getting out of the kayak when I should have, opting to just heave my weight back and forth until I was free of running aground. Throwing your weight into wearing down a kayak rubs it down much quicker than routine drags with a strap.
I weld my boats and rebuild this area for a lot of fellow anglers. I use a variable heat gun with scrap plastic and use a glass rod or wooden rod dowel that I dip into water to prevent sticking while shaping it. I build the area up thicker than required, then use a Dremel tool to shape it and then smooth it and bring the oils back to the surface with the heat gun. Once I am done the area is better than new and actually a little thicker. Next time I do one, I will photo the process and post the step by step here!!
I recently wore a hole in the back of my plastic kayak from dragging it with the front handle all the time. It was a smaller hole. I used marine bondo with fiberglass to fill the hole. I also think it thickened the area nicelely. Took my kayak out a couple days ago. (stayed very close to shore at first) ;) the repair work and it floated like a dream. Let me know if anyone has any questions.