Not for Cake, but...
So I purchased this item to encase my dried bridal bouquet in epoxy resin. The size is absolutely perfect, and most resin-specific molds aren't large enough to fit something that size.
While it's still in process and I'm unable to take out the finished product, I test pulled away part of the mold from the already cured layers a bit and it pulled away super easily. The inside of the product is also shiny smooth, so I fully expect the completed resin to also be shiny and not need sanding/polishing.
As for the mold itself, it's not a solid rectangle of silicone; the "square" outside is connected at the top, but does not connect to the bottom of the hemisphere. This should allow for easier removal of your project (be it resin or cake!) but that also makes the mold more fragile and may tear over time.
By Kay, Florida on March 7, 2021