Movie: http://youtu.be/LktZsegiSIU

This is an analog heated bed for an Ultimaker [or every other 3D printer]. No extra hardware and electronics needed. Heated beds allow the user to print without warping the object. PLA doesn't warp that much, but ABS is known for warping.
One candle [waxiine lichtje] can bring the aluminium 3mm plate to 50 degrees. A double candle can go up to 60 degrees. I haven't tried a tripple candle. Other possibilities are a oil-lamp or a spirit burner[?!]
[Maybe with some electronics so you can change the flame power with a servo.]

cheers\joris
www.rooiejoris.nl
www.facebook.com/europerminutedesign

From idea to working concept: 34 minutes during the Utlimaker Meetup at ProtoSpace, FabLab Utrecht....

For the candle you can cut out a circle in the Z-stage. [I already made the hole in advance when lasercutting the parts...]
Make something that hold the candle, I used some metal wire.
Use a Aluminium sheet, tape the kapton tape on it.
Turn on the candle [wax light].
Place the aluminium sheet on top.
Wait till the platform is hot.
Start printing.

For a double candle i just made 2 hole in the canlde and put two wicks in one candle. Should works for 3 wicks as well.

Improvements:
maybe use a thicker aluminium piece above the flame... maybe use brass...
maybe put a thin sheet of glass on the aluminium to get rid of the kapton tape...
maybe use some oil between the glass en the hot plate to transfer the heat better...

Movie: http://youtu.be/LktZsegiSIU

To be continued...!

cheers\joris
www.rooiejoris.nl
www.facebook.com/europerminutedesign