One other thing that I forgot above, polyether blanks (Walker) don’t have the same density gradient as polyester (Clark) blanks do. In other words they tend to be more the same cell structure all the way through so there’s less chance of overshaping. One of the reasons Clark has so many molds is that they are stronger if you shape less off them. With Walker you have a bit more freedom to go at the blank and really just shape away. This creates yet another advantage/disadvantage balance between the two.
So does that mean Clark Foam Delams easier
I think it does per weight of foam although per foam weight Clark will finish lighter because the cell structure is smaller. The higher the density the less delam your going to encounter with either one. Walker foam takes a bit more resin which helps the bond but adds weight. This is a pretty nebulous question and much even depends on how your shaping the blank. If you stay close to the blank shape with Clark it makes a pretty strong board for a polyester. If you overshape a Clark you’ll definatly have delam problems. With Walker, you can’t really overshape. A lot just depends on what your doing. Again percentage differences.
are you talking about home depot light weight spackle?