side mirror bumped - now have fiberglass cracks

[Randy Krohn]

My side mirror in my '72 got bumped hard a few years ago. I now have what looks like stress cracks above and below the mirror mount (mostly above). A little paint has flaked off above the mount and it looks like there is very slight cracking in a very small area of the fiberglass.

What's the best way to repair this?

Thanks in advance to all of you experts out there who are conducting my Continuing Education!

Randy Krohn

[Tracy C.]

Re: side mirror bumped - now have fiberglass crack

Randy,

If the door skin in the area of the surface cracking is still rigid and strong, you might get away with taper grinding the surface in the area of the crack and and backfilling with fiberglass mat & resin.

If the door skin feels at all spongy in the cracked area, the only way to repair and prevent the cracks from reappearing later is pretty labor intensive.

You need to remove the guts from the inside of the door and taper grind the back side of the door skin in the area of the crack. Start about 3 inches from the damage area and taper downward towards the crack. It gets pretty tricky because you want the door skin to be paper thin in the area directly under the crack.

When you have all the grinding done, clean the area with acetone and replace the removed door skin material with fiberglass mat and resin. After this cures, grind off the sharp edges from the repair and replace the window/door mechanisms.

Follow normal body shop repair techniques on the exterior of the door panel (paint removal, sanding, bondo, primer & paint) to finish up the repair.

If you don't like his approach, you can also replace the entire door skin.

good luck,
tc

[Randy Krohn]

Re: side mirror bumped - now have fiberglass crack

Thanks for the tips. I believe I got lucky - the skin feels the same in the cracked location as it does anywhere else on the door. Another winter project...