are there anyways to stop a radiator leak like a sealent or something...i have this link on the bottom of my radiator...i dun't think there's any cracks but the paint is chipped..it's the size of a quater this is on my 91 integra

 

if it's metal, you can use metal epoxy like jb weld.
if it's plastic, you can use putty stuff.

if you cant clearly see where it is leaking and cant keep the area clean and dry for application, you are prob better off just getting a new radiator.