Plastic Kayak repair???

[timh]

Anyone ever repaired a plastic kayak. I have a Malibu sit on top two seater and the top side of the hull has some cracks where the carry handles mount. They are at worst 2-3 inches long and 1/16 wide. I bought the kayak from a tour company in La Jolla so all the hardware is corroded from the salt water. I plan to take the nutserts out and come up with a new system.

I want to fill the old nutsert holes and start from scratch. I don't want to go spend the money on a plastic welding kit right now. Can I use my 40w soldering iron effectively and does anyone have any pointers for me here?

 

[DesertBoater]

A soldering iron will generally be way too hot. Whatever you do, you don't want the plastic to smoke. Once it starts to smoke, you've gone above the working temperature of the plastic, and the repair will be very brittle. Also, UV light has a lot to do with the lifespan of the material, and for a boat that has lived its whole life in the sun, you'll notice significant fading of color and weakening of the plastic.

It sounds like you want to completely overhaul the hardware on the boat. If you've got your heart set on doing that you're probably better off buying a plastic welding kit. That said, the way that I've seen plastic repair done (for small cracks) is with a heat gun, a piece of filler plastic (they sell it in thin rods), and a putty knife. You'll want to clean the area around the cracks, and then bevel both edges so that there's a bit of a gouge that you will then fill with the filler plastic. You want to get the filler plastic soft enough that it will stick into the gouge and melt in with the original material. Stir the filler plastic in with the original stuff with the plastic rod until you get nice swirling patterns. The first round of this won't fill the entire crack, you'll take multiple (2-3) runs at it until the surface of the repair is as high or higher than the original. At this point, wait for it to cool, and trim it down so that it's flush with the rest of the boat.

Generally speaking, on a plastic boat, the hardware is at least half of the original manufacturing cost. The plastic/molding process is relatively cheap compared to stainless steel, bungee cord, and fittings. I'm not absolutely sure that the Malibu fittings are stainless steel, but I would certainly hope so. If they are, could you just replace the external bits? That would save you a lot of time, effort, and money. Also, you probably already know this, but stainless steel is just that...stain less steel. It isn't rust-proof, just more rust resistant.

You say that you want to remove the nut-serts and start from scratch. The reason that most companies are doing nut-serts instead of regular external/sandwich nuts and bolts is because it's damn near impossible to get a wrench up and inside of the hulls of most SOT kayaks...

I hope that all this helps...I guess it's kinda a lot.

Cheers,
West

 

[timh]

That helps a great deal. Thank you.

What about the 3/8" or so holes where the nutserts have been pulled out? Can those be filled or should I just put rubber plugs in them?

Also, is there a source that would have multiple colors of polyethelyne rod? Such as ACE hardware, Home Depot, etc.

Won't a heat gun heat up too much of the surface area? Seems like you would need something that would concentrate the heat to a more direct area. Or are you only applying the heat to the rod and not the kayak surface?

 

[kerry]

This plastic welder is pretty cheap and I think well worth the investment. I have a similar design plastic welder and I have welded a lot of stuff with it that has held up for many years.

http://www.harborfreight.com/welding/plastic-welders/plastic-welding-kit-80-watt-iron-67102.html

Harbor Freight also has other more sophisticated plastic welders which aren't that much more expensive.

 

[Hazzard]

I haven't personally done this but I had friends that patched their boats with plastic from orange traffic cones.

 

[squatch]

base welders for skis work also. maybe some p tex and a candle would too?

 

[\\'anderer]

I used the harbor freight kit, but I used colored rods to match my kayak.

http://urethanesupply.com/storepolyethylene.php

 

[Nullifier]

Usually the manufacturer will send you some pieces the right color for your boat if you call them. They have lots of scraps. I have always used a pair of vice grips locked onto a large drill bit with the tip in the jaws. Then heat the shank with a propane torch and to get it hot. Then work the plastic strip by placing it on the crack and pressing it with the hot bit melting both the strip and hull together.

It is very imprtant to remember that you have to drill out the ends of the cracks first or they will continue travel once repaired. As for filling in a large hole like the nutsert for get it. Just drill a new fresh hole there and put in a rubber plug.

 

[timh]

I tried some plastic welding rod with a pencil torch but the polyethylene rod didn't want to bond for some reason. I found what worked best was to simply heat up the cracked area and work it back together with the backside of a spoon. It did seem that using the boats own material is the best bet.

 

[refried]

to get material for patching plastic boats, shave some small pieces from the raw edge inside the cockpit rim. that way you know your using the correct plastic and it will match.

Duct tape also works great and holds up very well.
1 clean the boat as good as possible inside and out
2 apply duct tape over crack and rub with a spoon to warm tape and make it stick better.
3 add several layers inside and out and rub with spoon to make flat.

duct tape patches are very durable if done right and may last for years (even on whitewater boats)

 

[corbin8or]

I did exactly that! I had a couple holes in my boat and I shaved off some material from around the cockpit and the cargo opening. I used that to patch up the holes. same color so you can't even tell where the hole was...