Unless the lens is rated for welding (or solar) viewing--Don't do it. A lens that lets through IR does not mean that it blocks UV--And between the IR and UV frying your eyes, blocking just visible light is not enough.
One of the fun things is look for shadows on the ground (particularly through trees and bushes). They act like pin-hole cameras and protect lots if images of the partial eclipse on the ground. I found it to be more interesting than looking through a (proper) filter at the sun.
-Bill