Restoration. The cheap answer is to get a dremel and hog out the cracks right to the metal and fill them in with a two part epoxy, then sand, use filler and smooth out and paint. I've been down this road and for a couple of minor cracks it works. You are dealing with 60+ year old plastic. I've found that 9 of 10 items the cracks come back, especially the high stress areas where the outside meets the center post. For big cracks near the hub, forget it. I've seen guys use bondo and show everyone how nice it looks painted. Put it on a car you drive and show me how it turned out in a few months.
The proper way to do it, is to have it recast in the color of your choice.