If you could GET pure isopropanol, that would be fine, but the drug store variety is ALWAYS cut with water.

It is, as others have said, the water that interferes with the cure. Sometimes you can make rubbing alcohol work, and sometimes you just end up with a gloppy mess, so it's just not worth it, especially when you realize that denatured is cheaper anyway.

Last I checked, denatured alcohol was 2.50 a quart at the paint store, and isopropanol was 3.25 for a PINT at the drugstore. So, there is no cost savings in buying rubbing alcohol.

Oh and by the way, I do keep isopropanol on hand because it does a great job of cleaning up my hands when i get epoxy on them, and is not as toxic as methyl hydrate.