I just redid my grilles... if you have any questions let me know. I'm going to do a rundown of what I did.
I used a product called PC-7 for plastics/abs. Worked great.
1) First clean area of work
2) File edges of repair work to create a V in the plastic.
3) Have some sorte of backing, I used thin strips of metal and used them as a brace.
4) Take some clamps or such to make the jig or such as sturdy as possible, don't want the grille to move around.
5) Use the PC-7 And glue the backing piece behind the broken area.
6) Use the PC-7 and cover the V you made earlier in it, don't worry about it being smooth.
Let dry for 24 hours.
9) The two pieces should be joined together now, take some sandpaper and start sanding down the PC-7 overflow to make is conform to the grille shape.
10) Once sanded down, paint with whatever color you would like, black, argent, purple?...
I've also used this to make pieces I was missing in the front of the grille and on the back. I have a few pictures I'll throw up here in a bit to show you some of what I did. I left my camera at school the week I did the grille repair, and only have the first part covered.
Here are a few good links too....
http://www.automedia.com/Plastic_Grille_Repair/res20011101gp/http://www.moparmusclemagazine.com/howto/40625_plastic_working_techniques/Ryan
