Your best bet is buying the stuff they sell at the LFS (its the gel). Its $7 bucks, but the tube is huge and lasts forever. Much bigger tube than the stuff you buy at Home Depot, Valu, etc. But you should be safe using it. However, its not as good as the gel. The gel works much better for gluing to rocks. Good luck using the other stuff unless you have two perfectly flat surfaces. I've used the gel and the regular thin/watery stuff, the gel is way better.