Sunday, February 21, 2010
Restoring the A Pillar Fiberglass
Now that the left front A pillar is fully repaired it's time to restore the fiberglass. In 1963 Chevrolet engineers were not willing to bond the fiberglass body directly to the metal birdcage. Their solution was to rivet fiberglass bonding strips to the birdcage then bond the fiberglass body to these fiberglass bonding strips. In this picture I have riveted two original bonding strips onto the birdcage and added one home made strip, the black one, using bonding agent. These strips create a bed for the body panel. In this side view the two pieces of fiberglass you see were originally one piece. These will be repaired with fiberglass.
Bonding agent is black in color and has a toothpaste consistency. It was applied to the top of the bonding strips then the body panel was placed on top of the bonding agent, aligned, tabbed (using rivets), clamped, and allowed to cure over night.
The next day the clamps were removed and rivets were drilled out.
The side panel requires a fiberglass repair. Ideally, fiberglass repairs are performed from both sides, however, there isn't access to the back side of this repair. A backing strip will be required to hold the fiberglass in place.
Bondo was applied on the upper body panel to fill in surface irregularities and to temporarily fill the holes. Because I prefer repairing holes with fiberglass I drilled out most of the Bondo creating a pocket.
Cut up pieces of fiberglass were mixed with resin then used to fill in the holes.
Excess material was removed making a very strong fiberglass repair.
On the side panel I folded over a length of duct tape so there was no sticky side. Using needle nose pliers I pulled the duct tape behind the fiberglass creating a backing strip. The duct tape can be easily removed later because fiberglass doesn't stick to duct tape.
Multiple layers of fiberglass matt were used in this repair. If you look close you can see the duct tape on the backside.
The duct tape was removed and the fiberglass was sanded smooth. The bonding agent, Bondo and fiberglass resin received a final sanding then the area was masked off for paint.