How to fix ground effects?

copied from MSTANG

Automotive Aftermarket
Truck Line EZ Sand Flexible Parts Repair
08276, 400 mL, 6 per case

Two-part epoxy used to repair most plastic parts, including bumper covers, and other plastic body panels (not for use on SMC/fiberglass). Use 3M™ Polyolefin Primer 05907 for system II plastics. 10 minute work time, 30 minute sand time, 4 hour cure time

Buyer's Part Number : 08276
GTIN(UPC/EAN) : 0 00 51135 08276 8
3M Id : 60-9800-3708-3

ADDITIONAL INFORMATION
Automatic mixing. Designed to be used as a filler and adhesive. Epoxy based for easy sanding. Formulated for excellent feather edge.Flexible through a wide range of temperatures.

CHARACTERISTICS
Clamp Time
1 Hour
Color
Gray
Cure or Dry Time
4 Hour
Work Time
10 Minute
3M 1995-2001
 
i had a 3 inch tear in my front fender extension on my GT. i used this black bumper repair kit... 2 step epoxy and resin type deal, it's flexible and STRONG. i sanded it down, primed it, painted, just like new. and its not expensive either $7 tops.