I have done a number of things.
Dope? Naaa that cracks and leaks but I have done it in repair situations, reluctantly.
Wrap the conduit with ice shield, buy a lead plumbling pipe flashing 1" larger in diamater than the electric pipe, split it, fit the lead around the conduit, caulk between the conduit and lead where the seam will be in the lead. Wrap and secure with hose clamps and if you're really really really good at soldering you can solder the solft lead closed.
Also try...
http://portalsplus.com/retrofit_flash2_110.htm