stupid question, do copoly's float or sink??

Some float, some sink slowly; depends on the amount of fluorocarbon in the compound. They're all more buoyant than pure fluorocarbon though.

Some float, some sink slowly; depends on the amount of fluorocarbon in the compound. They're all more buoyant than pure fluorocarbon though.

 

"Buoyant" is a better term. For example, Yo-Zuri appears to "float" due to surface tension, but once submerged it will NOT

float up. For fishing purpose this line will not draw down topwater lures nor raise any bottom contact bait.

Copolymers are a blend of 2 or more nylon polymers, melted together and extruded into a monofilament.  Most brands of monofilament sold today are actually copolymers whether or not they are advertised that way.  And practically speaking, all of them have fairly neutral buoyancy.