Good advice from Wes, running the rack. Start with 5 pound'ers and work your way up to what ever pair stops you at zero reps and than back down again. Remembering , no rest. Those 5 pounder'ers will feel like 100lbs. One of the few exceptions where you want to go to failure. Not to mention the unbearable pain along the way. Maybe once every 2 or 3 weeks should do it. No other curling exercise done that day. If your gym has 5lb advancement with the DB's, so much the better.
Also works with DB presses or lateral raises, very well. With any of these exercises you will be cheating for those last few reps. Pump is beyond belief if doing the set full throttle.
Alternate or together, might try incline DB curls, keeping the back of the head touching the incline bench at all times. Start with the thumbs facing forward, at bottom position. Twist the DB's as you curl them up. Thumbs should be facing out sideways top position, DB's touching the delts and elbows up high. One of the few curling exercise that follows the natural contraction of the biceps. Good Luck.
