One possible use of 3d printer, printed plug from PLA, treated with spray filler, sanded down, spray again, paint this time, polished and ready for mould making.
Nice Work!!
My english is not perfect: So what kind of plug is this? I think “electricity” when I hear plug, but this seems not to be one of those.
What product did you use as as spray filler? Looks really nice.
@Testa_Atset plug is the prototype of the object you want to produce, but these guys explain it way better: https://www.fiberglasswarehouse.com/fiberglass_mold_making.php
This is going to be stern fitting for sailboats to attach our gangways
@Michael_Audette we used polyester spray filler on this one, acrillic fillers also works on PLA, as also direct coloring with acrillic paints. PLA is very easy to work as far as painting concern, basically everything sticks to it pretty good and nothing does any harm to it, with ABS on the other hand you need to be a little more carefull with chemistry choices
looks like porcelain finish 
… it must have taken 3-4 grades of sanding?
something like that, 500, 800, 1200, 1500 then buff. Human hands still the ultimate tool 
freaking amazing