Hi QSR,
It depends on a few things as to the best way to repair ,the cheapest is to get some sheet metal ,cut to the size
you want ,place sheet metal on both sides of the plastic that's cracked and drill holes then use alloy pop rivets
or just small nuts and bolts . I've used stainless sheet metal from an old dryer centre drum that way you don't
need to paint the sheet metal and it won't rust.
As long as the crack isn't all the way to the front opening and the crack is open a little you can get away with using araldite
but this doesn't always hold to polypropylene but I always use araldite on both sides and in the crack and it's like an I beam
type of repair so even if the glue eventually comes unstuck from the plastic the plastic still can' t move anywhere as the
araldite holds the plastic together.
You can use a more suitable glue for polypropylene but it can cost a little more if you go that way .
https://www.loctite-consumer.co.uk/...er-strength-adhesive-for-tough-jobs.htmlA plastic welder would do the best looking repair but probably the most time consuming.
https://forgeway.com/how-to-weld-polypropylene/A hot staple gun does a quick strong repair but you would still need to spend dollars for equipment instead of just
buying a good second hand catcher from a tip shop for $5.if you can find one.
I've seen the early seventies VC mowers and the catchers were described as Green 'Armorlite' grass catcher, but
thought some catchers were polypropylene .
Another crude type of repair would be fibreglass (or alloy ,plastic ,sheet metal ,etc) and using pop-rivets to secure that to the plastic.
So it just depends where the crack is how bad the crack is , how much time and money you want to spend repairing
and does the repair need to look like it hasn't been repaired.
Cheers
Max