what can be fixed to pvc pipe to heat water?

[cptbahama]

Couple questions:
I am making a 8 foot section of 4" pvc pipe into a waterer. I bought some of the yellow nipples on ebay.
What can I apply to the pvc to heat the water and be safe for the pvc plastic material?
Would it be better to get a bird bath de-icer and make a reservoir attached to the top of the pvc tube with a 4" pvc "cleanout" piece?
In order for the water nipples to work, does there need to be a sealed vacuum in the water tank?? I mean does the water tank need to be closed or can it have an open top (in which to drop in a bird bath de-icer)?

 

[Chris09]

You could make something like this,

Chris

 

[southerndesert]

Here is another option...

sold here, but can be found at most hardware stores http://homesupply.tk/div-15979089-Heating_Tapes.html

 

[Quack-a-DoodleDo]

The heating tape works really great for keeping our house water pipes from freezing in the winter. Im sure it would do the trick for your waterer.

 

[TroutsChicks]

theres also aquarium heaters. those heat tapes come in 3 ft to 30 ft sections..and they cant touch the ground.