SB,
As Jay noted, Delrin is a dense, hard plastic and a great material for machining parts that will experience loads and stress. It's terrific machining properties also make it more difficult to adhere it to other things using glues because the surface is very smooth.
Mechanical bonding (i.e. screws) is the preferred method when working with Delrin. If this is not possible, an epoxy (2-part - e.g. Devcon) would be a better choice. If the part is actually Delrin and it's possible to do this, try roughing up the surface that you plan to adhere. Like paint, epoxies like and need tiny ridges to dig their little claws into for better adhesion.
RTV might work. It's a silicone product and would be much more flexible than expoxy. However, RTV is going to be more difficult to apply in small amounts because it's more viscous (thicker) than epoxy.
Hope that helps...
Tom
