I was in a similar situation as you before. I felt my arms were not being worked enough so I ended up over training them by doing them 2x week and going nuts every time. I shit you not I started training arms once every 10 days and boy did they start exploding, I kept adding LBS or reps with this routine. That being said, You have to experiment and find what works for you.
My current routine is such
Mon; Back/traps
Tues

ff
Wed:Chest/shoulders/abs
Thur

ff
Friday:Legs/calves
sat

ff
sun:bis/tris/abs
off
Its one day on one day off rotation: I do 12 to 14 sets Bis and 12-14 for tris. Super-sets heavy 6-8 reps only.
Hope that helps.