I've been shopping for a PA12 or project and have come upon a finished fuselage, unfinished wings with a flap kit & STC. How hard is it to add the pulleys and hardware to the fuselage after it's been finished?
When you say "finished" does that mean covered ???? There is a bit of welding involved---uncovered ---no sweat--covered--ya gotta problem---however fabric is patchable. Best ask your inspector.
I am in the process of putting flaps on and recovering my -12. If you do decide to do this project, I can fabricate the pulley mounts and various other pieces when I do mine. I planned on doing a couple of sets anyway. There are a couple of assemblies that need to be welded on and you shoud consider moving the turnbuckles in the cockpit if it has greenhouse glass. I assume this is the Day/Night PA-18 flap conversion.
keep in mind also to add flaps you will need mod your seat frame for the flap handle if you are not into recovering your fuse don't do it. it isn't hard but think of how many hours it will take you to do the job then times by 2 and that will be closer to what it will take.
things to remember, pulley mounts need an extra 'plate' or such that rear one in the 'vee' rips off tube.... so I make all mine as a 2 small .050" 4130 plates with the bolt/mount tube welded between them, and then you just weld(tig) the plate edges/unit to the tubes( easier when accessing through a hole in fabric) and many times stronger mount... wish I had a picture easy to find...
maybe I'll do a quick drawing.....
but its very easy this way and much better than just the tube welded to a tube....have fixed many of those.....