On Mon, 19 Mar 2018 12:11:08 -0700 (PDT), TimR
wrote:

Short piece of tape to hold it in place, then cover both sides with the fiberglas cloth from an autobody repair kit. These come with fiberglas reinforcement and the binder (either polyester or epoxy depending on how cheap you are). The repair is pretty sure to be stronger than the original.

+1

The fiber glass placed behind the grill, fast drying resin (add more
harder if wanted for faster cure). Easier than metal,, bolts, screws
or rivets IMHO.