After watching a DIY yourself video, where they used something called Amazing Putty...
...to make a simple mold, for chocolate, but it got me to to rethink part of my "Heavy from TF2" costume. I basically used chalk that was painted over to make the ammo belt, but after I made it, it turns out the thing is surprisingly heavy to wear and sags because of the weight distribution on it, so I was thinking using this mold idea, I could remake the chalk pieces out of something that is hopefully lighter if possible.
What would be a cheap filler to use that I could fill my mold up with that would work in this putty stuff and come out really light if possible, and be paintable.
Or if anyone has any other better ideas, I'm up for that also.