This rather depends on the environment the sculpture would be in because you will need to consider the UV stability of the resin you use. Also, it's not clear from your question whether you need the resin to be thick (like a filler) so that it can fill gaps or whether a normal liquid viscosity would be OK.
I'll assume that this is either an indoor or a semi-shaded environment (not permanent direct sunlight) in which case our XCR Coating Resin is a clear epoxy resin that would be liquid in its normal state, allowing you to direct it into cracks or gaps in the piece. It also has excellent UV stability (for an epoxy resin) so providing you're not looking at permanent direct sunlight then it should be fine.
If you need a thicker consistency then you'll find that anything you add to make the resin thicker will affect its clarity (making it milky) which may or may not be a problem. If you do want to make the resin thick (like a filler) then you could add Fumed Silica which is a white powder that can be added to resins to make them thick and self supporting.