Buy yourself a cheap glass vase, like this: Cylinder Glass Vase 5x16 and its Dimensions are 5" x 16" (plenty of length, you can get shorter if you want) for 10 $ plus shipping. Then get yourself some yarn, and some lighter fluid, and some ice. Then follow this videos instructions and use the yarn to cut the glass end off the vase and presto...you got yourself a sweet cooltube [ame=http://www.youtube.com/watch?v=Y9etHD9F90E]YouTube - Part 2 DIY cool tube[/ame]
Thanks for the science lesson! This is something i will be doing in the next few weeks to fit my conversion bulb. Girlfriend could use a little work on her camera skills though +rep
they sell pyrex round bread baking dishes on ebay pyrex will handle the heat and no cutting the end off as you will with the vase