As of 3/13/16, I am sad to report that the restoration did not hold up. I do NOT recommend using the KBS Coatings epoxy putty. After 2 years of storage in a box at normal temperature, all the epoxy putty had separated from the steering wheel and was beginning to fall out. I will need to find another solution. If you used this as a guide to restore your steering wheel then I am sorry if you have bad results. My intentions were good.
Here is a video showing how I grind into the crack. Keep a steady hand and you will do fine.
Cutting grooves in all the cracks took about an hour. A few times I accidently let the grinding tool wander and I nicked the wheel. So I had to cut grooves in places where I nicked the wheel. Of course, the numbers are taped onto the wheel for teaching purposes only. That way I can keep track of my before and after pictures and show you the process.
I'm sure other epoxy products might work well too, but I have had good success with KBS Coatings NuMetal Epoxy Putty. Wearing nitrile gloves is recommended. Mix in small amounts because a little goes a long way and it might begin to harden before you use it all if you mix a large amount.
Using latex or nitrile gloves, I pushed the soft epoxy into each groove. Be careful not to underfill the groove or you will have to grind out any low areas and fill again. Then wait 24 hours for the epoxy to harden. I know what you're thinking . . . "How's he gonna make the crack invisible when it looks like THAT now."
This video shows some epoxy putty being pushed into a few cracks in the steering wheel.
The epoxy will now be sanded down using the same multitool I used to widen the cracks. Just for fun, let's take a look at some pics of the early results. Next I will describe how I sand the epoxy using the multitool (I use a Ryobi, but a Dremel Tool will do the same thing).
The technique used to sand with the multitool is rather easy. You must use a light touch and work slowly and carefully. You MUST keep the multitool moving constantly and in a random pattern. I even suggest that you buy an old junkyard steering wheel and practice sanding a few repairs until you get the hang of it. The good news is that if you make a mistake and create a valley by sanding too deep, it's not the end of the world because you can still repair it later. Here are some more tips.
I just shot these 3 videos this evening, 12/31/12. They show the technique I use to sand off the epoxy. The 1st video is a bit long but the next 2 are much shorter.
Tight corner areas cannot be reached with the multitool. They need to be sanded by hand. Additional tools like small files and a sharp blade can help remove the excess epoxy.
The final sanding is complete. I missed a few places that will still need repair. Just a few dents. The next step will be applying an epoxy primer which might reveal a few more flaws. Perfection isn't my goal. Invisible repairs will be good enough for me. Just a few more samples of the final results before applying epoxy primer.