2' lengths of copper tubing? "Are brass compression fittings and brass flare fittings sized to fit the same size corresponding copper tubing?"A. Compression fittings and flare fittings are sized to fit the outside diameter (OD) of the copper tubing, so no conversion is needed. For example, if you have 3/8"OD copper tubing, then you would need to use a 3/8" c...