Well.. Yes. Here in DK it is known as Lego-glue as Lego's have been around forever, every household which has ever seen children has some and their made of ABS plastic.
ABS has been used for just about everything since the 70's and fortunetly for us it is a chemically reactive polymer, several solvents will dissolve it but acetone is by far the most common.
I've before used aluminium mesh to strengthen the back of seams before, but you could add fiberglass fibers to your putty as I've seen this done in the industry before.
Chop up whatever ABS you have (the finer the quicker it will dissolve, shavings dissolve almost instantly) add to a non-reactive closed container (old jam jars are perfect) and pour over a douse of acetone and let it sit at least over night, ideally stirring every few hours. You want to make the putty as thick as you dare adding as little acetone as possible as this is what needs to evaporate for the glue to set, a thin body-filler like consistency works for me.
Chamfer the edges of the break you are applying it to ideally removing the surrounding inch of paint to let the surrounding plastic breathe out the acetone vapor. If repairing a crack drill a whole at the end to keep it from cracking further.
Let it set for at least 48 hours at room temperature (keep it out of the sun as the heat will make it bubble) and you are good to sand the seam down, leave the plastic free to breathe at least another 48 hours before painting it over.
Works great and is dirt cheap.