Did my F-1 steering wheel a few months ago. Had a few cracks which I touched up with the Dremel tool. Used PC-7 Epoxy (Amazon Prime) to fill the cracks/dents. Hardens and can be sanded/shaped as needed. Wiped it all down with Grease/Wax remover (paint prep, TCP Global) and painted with Rustoleum Gloss Black Engine Paint. Looks great and no dirty hands.
www.pcepoxy.com