Sand casting (experiment)

I started my first sand casting as an experimant using sea sand. After making a simple pattern and using only half a flask it didn't really work out as you can see in my image. The best part about aluminum it could be remelted again and again, so I broke the casting and remelted it back into ingots.

This time I bought PETROBOND sand, I got one bag of 25kg it is a bit expensive but amazingly easy to work with and the results speak for them self.
My first proper obeject I made was a Star Trek federation insignia, the original pattern is made from plastic resin that I got a few years ago in a custom model kit box.
The first pour was very good but small part in the cavity didn't fill all the way so I tried again this time using only sprue hole without vent hole and it was perfect.