Plastic Grill Housing Repair

Deltatech said
The trick to using zip ties as filler is puddeling enough original plastic and mixing it really well with the Zip plastic, when I shape it I use a body dolly, get the plastic just the right temp(juuuuuust enough where it will compress) and mush it flat with the dolly.
You can just push hot staples in the plastic to hold a bad crack together enough to fill it.
PLastic welding isn't common knowledge and a lost art.

This is what I got from harbor freight to fix a badly cracked bumper cover on my Dodge Journey. It worked great. I drove it in bad weather conditions and it hasn't cracked again. First time I used it and it worked easy. I bought some extra plastic welding rods and I don't think I even had to use them. It doesn't take much!
80 Watt Iron Plastic Welding Kit