thank you very much,
First I bent an open top box on my aluminum brake the size I wanted it.
Then I line the box in tin foil and dropped a peace of plexiglass so I had a backing I could dill into, and gurrila taped it off.
Then I filled the box with expansion foam and let it dry and expand.
The I pulled it out of the box and cut out the tunnels until I got it the way I wanted it
Then threw on a couple of layers of grout
it was the first thing I made for the tank and then when I got to a point were I started trying to match stuff in place I found out that it needed to be much more squered off on the side that was going to butt up against the glass.
So I made a new box and sprayed the edges with foam to fill the gaps around the edges
Then I put 2 more layers of grout on it smoothing them them out to match the edges of the box with one of those concrete flat spade things, and let it dry
then I had to make a brace to lift it to the glass and hold it in place, out of 1x2s and 1x1s
hope that makes sense I don't always explain things so coherently, it all makes sense when I'm typing cause I can picture it in my head but sometimes it gets lost in translation. here's a few other pictures for reference.
I cant find any from before I covered it in grout
Thanks again for the great complement
-Matt