THat big one is a combination of thingys.. I got desperate at the end.. it was the last one in the top waterfall series and I didnt think I could tote one more bucket of cement and rocks up there for filler sooooo what I did was take foam cartoons, you can get them free at any pet store, they ship fish in them and I had some huge pieces of foam that refrigerators, furniture etc come packed in.. they are 3" thick huge sheets of foam.. also free and I cut it in blocks and stacked it up to get a basical shape. Then I used the great stuff to cover it.. I did that whole big rock with just one can casue there is so much filler inside and I can move it very easily. I did put two rocks in the back of good size cause I didnt want it blowing away up on that bank.
If you experiement with great stuff, there is really no reason to cover with concrete. YOu can put pits in it when its it semi wet, its very nice to sand it. Most of that is sanded worked with a sander and leaving small pits, bumps and ridges. Then I took some admin mix, which you can buy it lowes in a bottle. I mixed two parts cement and one part of that liquid and painted the whole thing.. it gave the color of cement and though it waterproofs cement, I do not know if it waterproofs the great stuff or not but it did give me the color of a cement rock to start with. I dont know though that I would have to have done that as I could have painted the great stuff.
I am so unconventional I hesitate to tell poeple how I do it in case it dont work for them.... Some things I do work and some dont and none are proven in time yet
but that rock is on its 2nd year now and looks the same.
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