How to paint a detached arm

For one reason or another I have started to paint a few of the arms separately from my Chaos Space Marines. Some of the arms are posed holding a weapon across their chest - this makes it very difficult to paint behind it - and I have also started magnetizing a few of my troops arms.

The easiest way I have found to paint a detached arm is as follows -
  • Lay the arm on a sheet of cardboard and prime one side
  • Let the arm dry and then flip it over and prime the other side
  • Take a cork and place a piece to poster tacky on it
  • Stick the arm to the tacky and paint as normal
  • When you are done remove the arm and affix it to your model
This is one of the arms I am going to be magnetizing for my special weapons selections. It is a comb-flamer that I pieced together out a hand flamer and a bolter.