Well, the icebergs are done. That is a big step for this next image. The translucent greyish bluish parts are cast from resin in my custom molds. The whitish snowish looking parts are plaster that I left on the resin. The smaller berg was broken out yesterday and was relatively easy. The mold for the bigger one wasn’t sealed properly and so the resin soaked into the plaster. That meant it didn’t break out and I had to grind it down to the resin, which took forever.
These are two cutter bits that I bought for my rotary tool for this job. The one is unused and the other was used only to get larger iceberg out.
Gardner Art and Stuff 
These are amazing! I am researching icebergs and resin casting right now, as I’m beginning a diorama of Shackleton’s Endurance caught in the ice. Thank you for posting this info and lovely pics! Now I need to check out your finalized piece. Cheers!
Thanks! Somehow I missed your comment when you posted it. I hope your diorama turned out well!