I have a pentium 4 1.7ghz and a nice aluminum thermaltake indigo orb:
thermaltake's spec page

so i want to make a combination of watercooled/heatpipe technology to cool my beast, heres a paint of the the holes drilled so far (attached), the fan is gone and the bottom has been lapped.
i plan on having my friend take some small aluminum piping and weilding it into the holes drilled and then having them go though a small radiator and back down into the heatsink all sealed.
But i dont have 1) money 2) space to put in a pump or a res, hence heatpipe.
So i ask::
1) what liquid has a low enough boiling point to be use instead of water in a heatpipe? (including refrigerants)
thanks, tux