first a proper HOME repair might not be possible economically due to equipment costs and materials.
we use 3M plastic repair system at our shop.they are dual cartridge tubes with special mixing tips. they also require the use a special applicator gun to use also.
i think the cartridges are in the $75 range and 2 tips are included.
don't know what the gun costs, we got ours for free when we bought a starter repair pack.
the first test is cut a SMALL strip of plastic, put in in a small amount of water. push it to the bottom. if it floats you will need adhesion promoter before the epoxy.
adhesion promoter is also around $40.
sou might need a reinforcement mesh to support the repair also, depending on where the crack is.. i don't know what that costs.
after it's glued you will need plastic body filler material, plastic primer, them paint.

this is the cost to chemical repair. now if you find a body shop with a plastic welder the crack could probably be repaired in 15 min and the rod is $5.
them plastic body filler and primer. then paint.

our shop rarely uses glue to repair plastic anymore, depending on the plastic being repaired. most of it is welded. better repair, faster repair, stronger repair and cheaper repair.

SEE MY FIRST POST.