Remember when someone trashed my R1 a couple of years ago? I still have the fairing that goes under the seat. Insurance bought me new parts, but I kept the old fairing with a crack in it. I thought I’d repair it and sell it on eBay.
So what’s the best way to repair it? My first thought was epoxy and a fiberglass patch on the inside (the fairing is plastic), but I wonder if I should use some sort of glue in the crack itself. Maybe cyanoacrylate?
Assuming it’s ABS, this forum has some ideas.
I also remember reading (years ago) about someone who welded ABS with a stick of ABS and a propane torch in much the same manner as you weld metal.
Cyanoacrylate is mostly good for mating flat pieces together. Use epoxy and some fiberglass, you only need to fill the crack and put a small strip of glass on the back. You don’t even need that much backing strength, a piece of nylon cloth would do just as well to keep the crack from opening up again. If it PVC or ABS there are simpler 1 part glues that will work as well.
With fibreglass repairs any cracks should be entirely ground out. Even to the point of cutting out cracked sections if they go all the way through and then building them up again fresh with new fibreglass.
The reasons for this is if you fill the crack it will eventually come back out through the finished surface due to vibrations.
Of course this does depend if we are talking about lots of little cracks from a crushing type impact. If its one big crack between two pieces with no smaller cracks radiating from it you can probably just bridge across the gap with new fibreglass. I would just make sure a bridging fix is nice and thick on the back side as its still possible this crack could eventually show through the finished surface again after putting a few miles back on the bike.
These chaps recommend using a soldering iron and melting plastic into the gap, like runner pat mentioned above…
http://www.high-speed.ismysite.co.uk/phpBB3/viewtopic.php?f=26&t=15175
I haven’t read the other thread but if it’s abs (the type of plastic may be stamped on the piece somewhere) you can use abs glue. You should be able to find it in the hardware store in the plumbing section since ABS is commonly used for plastic plumbing pipes. ABS glue is a solvent cement, it will chemically melt the plastic together - you could even use some small pieces of abs plastic to brace it if necessary. ABS pipe and fittings are the black ones, the white ones are PVC plastic.
I had an abs motorcycle fairing that was damaged and ABS glue worked great on it.