what is the best way to put cab corners in an 87 ford ext cab. what to use to cut the old ones out.

 

I put a peice of masking tape level around the corner and used a die grinder with cutoff wheel to cut at the edge of the tape.
Then from what I cut off I cut a 2' peice grind paint off and bonded it to the inside of the cab. Then cut cabcorners and used Fusor (glue) and bonded cabcorner to the peice I just bonded in. Grind all paint off mating surfaces .
I drilled holes and used sheet metal screws to hold peices together till bonded.
I done it this way because I didnt have clamps big enough.
Then removed screws and skimmed with putty. Sanded and painted with primer.
ZZ