Are you saying you're trying to make them hollow for a dewar effect? I'm not sure if they'll let you do a hollow wall as it's really annoying to get the excess

Are you saying you're trying to make them hollow for a dewar effect? I'm not sure if they'll let you do a hollow wall as it's really annoying to get the excess powder out from enclosed volumes (via a small hole usually). With 3D printing - you do get volume discounts, but Shapeways has always reached the max of these discounts. After this, the companies need to start dropping machine/material prices and engineering for less labor in the post-processing.