Bodyweight skull crushers on a bar at the squat rack right into close grip sissy pushups for tris and bis stsnding dumbbell curls for reps super set with hammercurls for reps great pump....i like alot of volume get the blood engorged in your arms than keep blasting them with moderate to light weight you gotta stretch that facia

Imo supersetting arms works pretty good if you like supersetting just keep in mind arms adapt pretty fast from what I have experienced.

Close Grip Bench Press supersetted with Seated db curls (on a 30 degree angle if you like)
Tricep weighted dips supersetted with preacher curls
Skullcrushers supersetted with hammer curls
Tricep pressdowns supersetted with reverse grip cable curls

Keep in mind that the tricep has three heads and you want to hit all three of them, same goes for the bicep wich has 2 heads. As for rep ranges I suggest
Triceps 3-6 MAX 8 hit them heavy
Biceps higher reps because they are more slow twitch dominant as where the triceps are more fast twitch dominant.

Fapping. Hits the biceps, forearms and if you really get at'r it'll work the delts too.

Well...to max out biceps you need to hit the bicep with different arm angles to work it completely. Preacher curls are good (elbows in front of shoulder), barbell curls -great for mass (elbows in line with shoulder) incline curls or drag curls (elbows behind shoulder). Swap in DB's also so you can supinate the wrist on the way up.

For tris I like skullcrushers and pressdowns.

For biceps - barbel curls when lying againt an incline, concentration curls.
Triceps - weighted bench dips.

bunch of liars! Masturbation, make sure you switch arms regularly....

My favorites are dips, ez bar curls, spider curls and reverse close grip pullups. Something I've incorporated lately is db skull crushers and the pump I get doing them is serious!

I like standing dumbbell curls and DB preacher curls.

I got the guns up to 22. Favorite arm exercise is (you're gonna laugh) - straight bar using the old arm blaster that Schwarzenegger used. But. this is strictly a bicep exercise. I'm 260-280 when not competing but recently I decided to balloon up to 310.

See pic at ebay:

http://www.ebay.com/itm/like/230864237585?lpid=82&chn=ps&ul_noapp=true

For me personally when I'm trying to make my arms grow I like high volume sets, more work for the muscle seems to be the ticket in my case. Try 21's and reverse grip curls with an ez bar as Darth stated and I also like hammer curls using a rope and cables

With 20" arms, I should be asking you for advice.

Think along the lines of volume rather than a specific type of exercise.

If your doing enough variation to hit the muscles from all angles it's probably just a question of volume now. Switch it up a bit, extra sets, extra reps, drop sets, run the rack on cable machines.

If your joints can handle it skull busters and nose breakers they are too hard on my elbows these days close grip dumbbell press I like keep the Dumbbells touching dips again if your joints can handle it kickbacks as well the main thing is to keep changing routine so muscles stay confused also weight is not quite as important as failure every set should be failure for reps you want if too light go up on weight failure works for me and I can use a weight that isn't hard on my joints