Thumb mould riser volume

[JonathanRaines]

As the thumb grip pad is casting, bubbles in the Urethane rise to the top. These escape out the riser but reduce the volume taken up by the urethane in the mould. The surface level of the urethane, therefore, descends through the riser and down the model. As a result, the thumb tip is missing.

This can be fixed by increasing the volume of the riser. Any reduction of the level will happen in the riser and not affect the part.