"Hail, Hydra! Immortal Hydra! We shall never be destroyed! Cut off a limb, and two more shall take its place! We serve none but the Master—as the world shall soon serve us! Hail Hydra!"
Coming to wider prominence during World War II as party of the Nazi war machine Hydra has long been a thorn in the side of global security and stability. The group has been involved in numerous plots and schemes over the years, but none as great as their covert take over of SHIELD.
-=Design=- I really loved MAKOTOKAMUI's Shield Badge (http://www.thingiverse.com/thing:1462288) but couldn't find a Hydra badge I liked to go along with it, so I modeled this in Blender in the same style. I also included a small tab on the back so you can more easily attach a fastener.
-=Finishing=- I printed mine in ABS, then used hot acetone to smooth after a thorough sanding. I then primed the pin black. For the red pin I carefully painted the top layer red, and then sealed. For the silver version I used a heavy dry brush of silver acrylic paint and then sealed. I attached a rectangular pin backing I purchased at a craft shop on the back.
Print in any material. I recommend sticking with a default 20% fill. The pin will look fine up to a .2mm layer height. There's no need to print with support.