I have been trying to use clamps instead the screws. My problems are i have tried two different clamps the first ones were the blue vise grip not the smallest but middle size the molds would blow out i clamp two at the same time. So the next ones i bought the heavy blue vise grip it works but still it will blow out sometimes. Was thinking if i need to block sand my molds to make them flat. Has anyone had a problem like this. Also just tried a microwave today. What do you use to stir your plastic with. I used a spoon but it would build up plastic on it. Cub48