hot glue injection mold (feet)

i made this as an fun experiment.i chose feet cause hot glue seems like a good grippy 
material.  unfortunately I have not had success so far. 

-fill both halves with mold release or similar product

-clamp them together 

-put the hot hot glue gun in the opening

-squeeze until you get squeeze out from the exit holes

I would love to experiment further, any suggestments are more than welcome. 

ironing really helps for a smooth surface and easy release (I think).