I swear that we have discussed them here, but all that I found was this thread from 2013:
Making a Fiberglass Mold by some guy named Red Pointer?
I don't know.
He (or she! [judgmentally] I don't judge!) wasn't able to make it work.
I have looked into this from time to time, but I doubt that far back.
The only thing that Bob did that I hadn't done before (besides built-in outlets) is using white concrete.
I had never heard of white concrete!
They put a fiber mesh in their 11-foot island and it came out great!
I searched for white concrete and the first result that I saw was this video:
He said that he couldn't buy any white concrete mix locally, so he used white sand, white cement, and pea gravel, which confusingly, wasn't white.
The cross-section reminds me of a Big Hunk candy bar.
He used white aquarium gravel last, but it wasn't as strong. He felt the aquarium gravel was weaker.
Home Depot shows white pea gravel, but it would be vastly cheaper if you could buy it directly.