Here are some tips on repairing motorcycle saddle bags. This information was gleaned from various email newsgroups.
I don't know who posted this info; let me know and I'll give you credit! In the meantime, thanks for helping your fellow motorcyclists!
There is a very easy repair available at Home Depot or similar stores. Oates ABS plastic pipe glue. It is in the plumbing section. It is a very thick black plastic that dries without heat.
I have repaired several bags with cracks and even a melted hole and it is holding up great. For the cracks I used tape on the inside and forced the thick glue into the crack with a piece of flexible plastic. I didn't even have to sand the finished product and it is nearly invisible.
The bags are made from ABS plastic.
I've seen other recommendations to use fiberglass repair, Bondo, etc.
I would think permanent bonding to the plastic would be very difficult since ABS is actually a very hard and slippery substance. I have repaired cracks and small holes by buying dowel of ABS plastic [black in color - you can buy them from any industrial plastics store, there is one in NYC called "Industrial Plastics" on Canal St. in China town], shaving a section of the dowel -- to get "cheese grater" type shavings and then in an old glass jar mixing the shavings into some methyline chloride ["Weld on 3" is a good brand].
The ABS shavings will dissolve into the liquid, you can thicken the mixture by adding more shaving. It will take about 5-10 minutes for all the shaving to dissolve. Use a ice cream stick or chop stick to mix the contents.
Roughen up the surrounding repair area with some 220 grit sand paper; then spread the thick ABS mixture over and into the repair area. I usually do it from the inside of the bag and place some wax paper or foil on the other side to minimize the leak through.
Once the repair area cures, you can touch up the messy edges with finer wet/dry sandpaper. This type of repair will permanently fuse to the existing bag material. Lastly, make sure if you do this repair, that the room is ventilated or do it in the garage with the door open and a fan blowing the fumes away from you...
It is a pretty easy, low mess, repair job.
I have found a simple solution that works. I have been following the threads on repairing bags on a couple of the lists and one suggestion was to make up some liquid plastic by melting ABS in a solvent. I thought about that and remembered an ABS glue at Lowe's.
I went and got a can to try it out on a couple of bags with a cracks and 1 with a stress break at the back mount. It is a thick black plastic that holds in place well and cures without heat etc. Works Great. It fills and binds.
Look in the plumbing section with the plastic pipe glue. It is Oates Black ABS Cement in a blue can. No mixing, no heat!