C-Forum

I'm converting my C-1 polyethelene boat back to K-1 to sell it to a kayaker. I have four 3/16" drill holes which I need to fill. So far I have tried Plummers Goop and GE clear silicone sealant. They're ok but I have seen better on other boats. Any suggestions?
Thanks,
LarryD

Perhaps you could try p-tex wax... I used to use it for my skiis, You light the stick and drip it into the gouge/hole... you might have to get creative w/ it not dripping through the hole, but that shouldnt be a big deal... once the hole is filled you can scrape off the excess and you're done...

Not sure if this would work, but i think ill try it on my boat, ill let you know how it goes.
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Ladder Day Saints - Mormonism Forum

How about using a nylon countersunk screw and nut? That's what I've used.




Do a search for 90241A572 on the McMaster Carr page. (mcmaster.com)

The counter sunk nylon bolt sounds like a good permanent fix and I may try the wax idea too. Thanks for the suggestions.
LarryD

I recently bought a plastic welder (cost about $130) to fix a kayak with some cracks etc. The welder is basically a glorified soldering iron, but it has a temperature control knob which sets the tip temperature correctly for melting the particular plastic (the proper temperature varies a lot between different plastics).

One of the supplied tips accepts plastic welding rods, which slide through a hole in the tip and work similarly to metal welding rods. The kit came with about 8 different kinds of rods, for polyethylene, ABS, urethane, and several other plastics.

To use the kit, you clean the plastic with soap and water, dry it thoroughly, then weld about halfway through. You finish the job by welding the other half from the other side, which may not be possible in all cases, in which case you do the whole weld from the front, after placing a temporary backer plate on the far side. By working carefully, you can fill the holes and make the job almost invisible. We fixed a kayak that had a two inch long, 1/4 inch wide split in the bow, hard to tell where the split was.

I do not recommend using flaming Ptex to fix your boat. At best, you will partially fill the hole, but you won't get good bond to the existing plastic. At worst, you will make the hole bigger, or fill the hole with charred Ptex, which will not look good. The problem with the flaming Ptex approach (I know from experience) is that the Ptex comes out too hot, and is difficult to place in a controlled manner.

Last alternative is to bring the boat over to my house with a sixpack of quality beer, that usually convinces me to get out the welder. Course you have to get to the Boston area....

I would certainly take you up on the 6 pak and one for me as well but, I just calculated the milage to Boston at 1653 miles looks like I'll have to pass on that generous offer.
I also have a badly cracked boat which is currently just a house ornament. I attempted to weld it with a propane torch and it did hold for several more trips but it cracked open again. I would love to get it back out on the water again.
Your welder sounds great, whats the name of it? Possibly one of the merchants here in town may have it or I could order it on-line. I appreciate the info. Thanks,
LarryD

Larry;
Have you tried 3M? They have a glue/plastic/hi-tech material to fit almost any situation. Also, how long is the crack on your other boat? I had great luck on a Gyromax by drilling a small hole at either end of the 6-7 inch crack (to keep the crack from spreading ) and then gluing a piece of raft material (I think it's called Hypalon?) over both inside and outside. I used a roller to get it on really tight and it lasted for 4 years of outside storage and use, up until I sold it.
Hope this helps,
Ric Taylor

This won't work for cracks, but for old drill holes this is fast, easy, and has lasted YEARS (10 and counting, I think) on some of my plastic boats-hot glue. As in arts-n-crafts hot glue gun. I usually put duct tape on the inside to keep it from running right through, then fill'er up, and once it's cooled remove the duct tape (or not, depending on your aesthetic preference).

I, too, want to know more about that Plastic Welder-that's something I would seriously think about purchasing and lending out at Armadas....

Ric,
Good to hear from you. The crack is a monster. About 15 inches long running along the cockpit rim in the thigh brace area. Putting pressure on the thigh brace makes it gape open. The hypalon idea sounds good. The plastic welder mentioned above certainly has my attention too. Many good ideas surfacing here. Thanks,
LarryD

Sir Adam,
Very good idea with the glue gun. Hard to beat 10 years and still holding. Lots of great suggestions coming in. Thanks.
LarryD

The model is the Miniweld Model 5 Airless 5500HT, available from Brady's Tools (www.bradystools.com). As I noted, this is basically a specialized soldering iron, but it seems to work quite well. For high performance (i.e. rapid) plastic welding done on a commercial scale, most folks seem to use hot air welders, with adjustable air temperature and flow, but a decent air welder is at least $350, compared with the Miniweld, which I got for about $130, including a bunch of rods.

So far, I have fixed one kayak, a plastic bumper with a hole the size of my fist, and a cracked plastic auto mirror housing.

The instruction book has a good tip for fixing a large crack. Enlarge the crack by cutting about 1/3 of the way through the plastic, using a dremel tool, router, or V-groove bit on a zip tool. Make the groove about 1 inch wide (half an inch on either side of the crack). Then cut a piece of stainless steel mesh (they supply a small piece with the tool, or you can get stainless cloth at the hardware store). Push the mesh into the groove, then plastic weld over the mesh until you are flush with the surface with the plastic. Apparently the weld is as strong, or stronger, than the original plastic. If you can get to it, do the same thing from the other side. If not, use duct tape on the back side as a backer for the plastic.

Good luck.

Thanks for the tip. I just got the exact plastic welder on ebay for $119 plus $8 shipping. Can't wait to get it, I'm sure it will take some practice. I have a 15 inch crack in a high stress area and some holes to fill. I'll report back on how every thing goes and how well it holds up.
LarryD

i found these things at home depot called hole plugs. these things fit perfect in the hole and have these little teeth which keep them secured in. added a little silicon and WABAMM. dry as a bone.

you'll want to make sure that the boat in question is not a cross linked type of plastic. Most kayaks nowadays are made from a thermoplastic material, meaning that under heat it flows, but sustains no damamge. Older cross linked boats are thermoset, meaning that they are heated just once in the fabrication process, setting them, and aditional heat will actually decompose the plastic.

There is another process to weld other boats (I had an New Wave Attitude fixed (FYI the attitude is a great beginner kayak, but a lousey beginner C1)), and there's at least one fellow in PA that can do it, and fairly cheap at that ($70 if I recall, for a 12" crack in the hull that was perpendicular to the boat (ie. went left-right across the boat).