Making a Bourdon pipe shouldn´t be very hard either, basically it´s just a somewhat flattened nearly circular copper pipe. Could be bent with Cerrobend or equivalent. The problems I think would be in the pointer mechanism. A Bourdon tube has only little movement, so "gearing" that small movement up into a long pointer swing, that will be +/- accurately repeatable, will call for some watchmaking skills. Somewhat similar to building a test dial indicator (if you´re willing to sacrifice one, then you´re over halfway there ;D ).
Another awkward thing is to get a +/- uniform scale when calibrating. Meaning there should be clear separation between the (meaningful) pressure readings, so they won´t be all in almost the same spot on the scale. That depends mostly on the tube dimensions, length, wall thickness, etc. Might need a bit of experimenting ???
If you build one, use it often, and calibrate it many times during the first year, the readings are likely to shift quite a bit when the tube slowly work hardens.
If you want a dependable small gauge, it´s likely to be expensive, either directly on your wallet, or in the time needed to build and test several before you get it right.
Being an electronics engineer, I'd do it with a solid state sensor and a meter. 
