It will work. But you have to use a ton of it. One of the reefers that I've had quite a bit of contact here with uses it to glue frags to rock, and to glue the small rocks to the larger reef. Because it's a liquid, and the rock is very porous, you're gonna have to use a lot of it. He often uses 3/4 of a bottle to glue a rock to the reef. Personally I'm not a big fan of the putty epoxy, I think it's ugly if you don't get it hidden well, and it's expensive, and you need to use it pretty liberally as well. I found the cheapest way to buy the superglue locally is at some of my local dollar stores, that sell a 12 card sheet of them for $1. If you're going with one of the name brands, or the thicker gel type, then the cheapest way is to hit craft stores and get the largest bottles they sell.
B