repair suggestions needed

[yangjianhunt]

Hello Fellow yakkers,

I've been trying to repair the deep ding and gash on my hobie kona using marine 5200 fast cure.

I sanded (with 200 grade sandpaper) the gash/ding down around the area and also on the gash/ding and then dry wiped the area just to get all the find plastic powder off. Then I applied marine 5200 fast cure. It hardened after 24 hours and feels flexible to the touch but kind of solid.

but when I took the kayak to the bay yesterday, I noticed that the marine 5200 patches were coming off.

So my question is : Do I need to prepare the plastic differently (such as ethanol wipe and touch dry) to get 5200 to work? Or it's just that 5200 may not work?

I've also found many people say that G-flex epoxy is very good. There is even a video (commercial) showing a guy saw a kayak in half and glue it back up (http://www.westsystem.com/ss/g-flex-torture-demo/" onclick="window.open(this.href);return false;)

Of course there is the option of weld-repair the damages..Do you guys think this is a better /more permanant option?

Thanks very much!
Jian

[Tallgrass07]

A photo of what you're trying to fix would be helpful. Plastic welding is probably the best option for the gash.

[jfraymond]

Melted polytarp....cut tarp into strips.get a putty knife hot with torch or heatgun and melt it down over effected area just like you would tape and float a sheetrock seam.

http://neptunesrangers.blogspot.com/201 ... r.html?m=1

[Yak'Razy]

Melted polytarp....cut tarp into strips.get a putty knife hot with torch or heatgun and melt it down over effected area just like you would tape and float a sheetrock seam.

I saw a video on this... Talk about crafty...!!

[yangjianhunt]

Thanks guys for the very informative responses-
If anybody has any experience with west systems G-flex, it'll be nice to know how it works-

The welding and the polytarp method both look appealing-

I think I will try welding first after I get some matching color plastics from hobie.

But I can see the polytarp method is better than welding in a situation where it's fast to repair large areas of scratches, possiblly due to that polytarp melts faster than polyethylene. If it really sticks well, we can even apply a layer to both ends of kayak as a protection.

[preacher]

I use the welding method.
I just use a basic stick type soldering iron.
I use the plastic electric wire straps for welding rods and you can just about get any color you want from Depot. I use the 11 inch straps (or cables or zip ties) what ever you may call them.

Watch as much plastic welding as you can find then practice on your crate or something else until you learn how to puddle and weld. I found that my brazing experience came in handy.

I also use a 1 inch metal putty knife for smoothing. I use my heat gun to heat up the putty knife so it melts the plastic on contact and carefully smooth the welded area.

Then use different grades of good sandpaper to further smooth and blend.

Use a mask, the wire ties smoke up a storm.

[yangjianhunt]

Just to follow up on my repair trials:

G-flex:
Bought it at west marine for 30$--you can get it at amazon for a few bucks cheaper.
It's easy to use-but need to follow instruction to clean and prep the plastic (heat gun or torch)
After curing, the G-flex is hard to the touch, a little flexible.
It held up really well in water. It didn't soften or tear up like marine 5200 did.
I think marine 5200 is too soft for repair surface damages.
Also when I used 5200 I didn't torch flame treat the surface, which might be a reason for not bonding well.

Welding:
harbor freight sell the welding kit for 15$ and works well.
Welding of course worked well in repairs and doesn't crack or come off.

All in all, I recommend both G-flex and welding. Welding is better in strength and bonding.
But G-flex is quicker.