Having tried similar things, I cannot stress enough how much you want to be printing molds like this in TPU unless you really really want your mold to be permanently embedded in the concrete
The advice on sex toys (not cement!) I’ve read suggests using beeswax. I wonder if this would work as well🤔
Pla and a heatgun works but its not ideal. Definitely takes a while to melt off from more complex geometries akd isnt reusable.
In theory ABS is acetone soluable but ive been having a hard time coming up with a usecase where acetone is preferable to anything else
@RegalPotoo @Wilshire good point. Release agents are used for casting concrete. They look to be oil and water mix so I’m guessing most plastics would be compatible.
Also has to be a clear path out for the print/concrete.