.Here is the "Cheap & Dirty Plastic Crack Repair" topic By Wheelman-111...
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Greetings:
Like many owners, the stress of repeatedly removing 22 year-old ABS had caused some cracks to appear in my well-worn skins. Here's an easy repair method pictorial.
Prep the area inside the crack with a dab of Acetone. You must be over 18 to purchase this legally. Kids, don't huff this stuff.
Takes the pain off the plastic, which is not tinted through-and-through.
Next you really need only 3 things:
THe black stuff is 6-oz. Gen-you-wine low modulus carbon cloth. If anyone builds or repairs sailboards in your area, the scraps will last a lifetime of scootership. Don't use Mom's good scissors. There will be consequences...
Cut a couple of patches the size to bridge the crack - some photos are of my other cover, but the process is the same.
The stuff is slippery and wants to unweave itself, leaving annoying "hairs" all over. The GF will get suspicious. Handle as little as possible.
Next take the handy "All Purpose" cement and DAB, do not stroke it on. Place the patch over the crack and keep dabbing until it sits down. It follows contours pretty well If it tries to lift off, see below. BTW there was no specific "ABS" cement at Home Depot, just this stuff and PVC Cement No experience with that, but smells - and may work - the same.
Dabbing what's on the little round sponge at a time seemed to work best.
Let it dry completely without going back in the can to re-wet. That seems to be as much quantity of cement as can be applied in one "Coat".
If you're trying to get it into a groove on the plastic and the carbon cloth keeps "bowing" up, you can use plastic wrap to mold it down until it sticks. Of course that delays drying time considerably... Peel it off very carefully, pulling nearly parallel to the repair to avoid lifting the cloth off with the plastic wrap.
You can add layers of woven fiberglass for a more flexible repair. That carbon cloth is extremely strong, and 2 layers is plenty stiff. More and you risk having the plastic crack at the edges of the patch.
Anyway, sorry for poor phone-quality pictures, hopefully they get the method across. Happy Patching!