Thanks for your encouragement and comments!

I'm working with a 12,000 psi dental plaster, and found that it doesn't "crumble" easily when I try to break away the corners with a plier.
So I'm thinking of either using a hammer and nail to chip away, or use a nipper.

@Andadas That was my first attempt at painting yellow, and I just can't seem to get a "cool" yellow color yet...

@darkitect I'm just starting out my 40K hobby with the "Assault on Black Reach" starter set, and I haven't decided on which Chapter I want to use yet. So I'm fooling around with various Chapter colors to see which I like best