I bought this foam sealant to patch up previously foamed areas in my waterfall that were in need of repair. Before using I had turned the waterfall off and let the old seals dry out, cut away seals that were decayed -- in other words did a lot of prep work. I gave this product three stars because it's an average good product. What I found in using this product was the following: 1) filling in cracks where some of the old product is still present is not advisable. This sealant for what ever reason did not form a nice adhesion to the old seals. 2) this product as mentioned in the directions (which by the way the font on the can needs to be enlarged so one does not need to take out a magnifying glass to read them) does expand tremendously. After using to fill in a crack or two, you will get the hang of how much to apply. 3) trimming the foam was easy and it tended to cut cleanly. I used an utility knife and hacksaw blade. However, what you will notice is that due to the nature of the foam, there are little air pockets that get exposed. This is not a problem for me, but beware if you are looking for a very smooth finished surface. 4) as I was trimming the foam in a side wall crack (where one rock is on the bottom and the other rock makes the side wall), the foam adhesion to the side wall rock was poor. In fact, in most cases I know there is not a good bond. This could be because I did not mold the foam right after applying but rather relied on the foams natural expansion to do so -- lesson learned. 5), the foam color is a deep purple even after letting it dry over night. So if you are looking for a true black, beware of this. 6) I was surprised how quickly the can emptied. I have a fairly small four tier water fall and reading how much the product should cover and the nature of my repairs, I truly expected one can to do the job. However, that was not the case. Hope this all helps.

Only after I used it did I see that if it is exposed to sunlight you must paint or stain it. That may be my bad, but are you serious? This is for rocks outside. The sun is going to shine on them at some point! How do you make a product for outside that can't be exposed to sun. We're supposed to paint crevices? Paint wears off. And as far as dispensing flat black - it isn't black. It's graphite. When it dries it's glossy unless you sand or cut it. You have to make sure the dispensing trigger doesn't unscrew all the time, because it will. It isn't an immediate expansion. It continued to expand over the course of an hour. And it works best under 80º, so if it's summertime in the south.... Wear gloves. Try not to touch it. With these products, not just this one, if you touch it it's hard to get off your gloves so it will end up everywhere you DON'T want it, too. Make certain your entire project is ready to be sprayed. This isn't like a can of paint. Do a little, now, then a little later.

Foam in a can...that's what i ordered, that's what i got ;)

Foam does not go as far as other brands I've used but did the job it was intended for. Easy to use and blended in well.

This was our first attempt using any Waterfall Foam, and we were able to get our waterfall flowing just the way we wanted using one can. If you follow the directions, this product won't disappoint. Just be sure to wear old clothes and use gloves because it can be messy.