George, To add my suggestions to the others,,
I bought a small cutter wheel for a Dremel tool and chucked it into my air drill. I used that to vee out the cracked areas. I mixed up some PC-7 Epoxy, (it is sold in hardware stores in my area) and filled in the cracks. I hand sanded the epoxy to get the original shape back, that was the most time consuming part. I primed and painted with lacquer. It had been done about a year, so far it still looks great.
