Foam/glue for stones for waterfall?

[Vermilion]

I am going to build a waterfall and I'm watching videos from youtube. Many use some kind of foam to seal/glue with and I wonder what foam it is and where I can buy it?

Check the video around 5:30.

 

[useless]

Stone adhesive.

 

[Vermilion]

Thank you, do you know where to find the ones that are gray/black, the ones I've found are foam colored or pink like the ones Biltema has.

 

[useless]

The foam does not tolerate UV light and therefore must not be visible, so the color is a non-issue.

 

[Peter2400]

Thanks, do you know where one can get the color gray/black, the ones I've found are foam colored or pink like the ones Biltema has.

https://www.dammbutiken.se/touch-foam-polyuretanskum-svart

 

[Hallerudsbo]

I have bought almost everything on dammtrivsel.se
Stig is very nice and helpful there