While Coraffix is quite good and I use it at this time also, you can buy Lactite super glue gel. It is gel not a liquid like Coraffix and I like it better.
Another issue is if your zoa colony is located on a smaller piece of rock that can be removed from the tank or it is attached to the main rock in your tank. Cutting zoas off the rock in the tank is just a horrible experience. You most likely loose some of the polyps. If this is the case Don't try to cut all the polyps you intend to cut off. You may cut some of the polyps and release toxins to the tank that may stress other corals in the tank. Just do it over a longer period of time, several hours or days.