craftgrrl | Best method for customizing a stainless steel flask (Reply)

I checked the memories and the closest thing I found was altoid/aol tins, so I apologize if this is repeat in any way.

Anyhow, I'm in the market for a hipflask and have seen some really cool ones, but they either aren't affordable, or take weeks to be mailed. My boyfriend suggested customizing one myself.

I'm looking at probably painting it because I want it to do a brightly colored geometric design. Has anyone done this? What type of paint did you use and were there any problems with condensation or temperature affecting the paint?
An alternative that may be easier in terms of execution of a design would be making the design on paper and then decoupaging it on. My concern is that this could be even less stable than the paint if wet or cold from the contents. Anyone tried this method?

Any suggestions are appreciated. Thanks!