Here's an alternative to cutting up a C02 cylinder for those that might not have access to a lathe or welder. This is sold as an oil catch can but, because it has a removable top, it could easily be converted to a vapor trap using the same method as above and at less than $30 it won't break the bank. These are available in Red, Blue, Black and natural aluminum.
http://www.amazon.com/Rev9Power-Rev9...B8N2W33ZJMQFFZ
