I am having problem with my left arm being a lot weaker then my right. When I do dumbbell bench press, I have no problem, but when I do curls, there is. I'll do 25 reps with a 45lb dumbbell, but then when I do my left arm, I can only get 15-20. Then the next set, I'll get 20 reps with my right, and 10 with my left. I don't want my right arm to become noticable bigger then my left. How do I fix this? I have a curl bar, I guess that can help control it, but I'd rather use dumbbells. Also, when during a workout should I do dips? I have been working out for about 4 weeks and I just got a place to do dips. I tried doing them at the end, but my arms were dead from all the other lifting. When I do it first, I can't finish everything else in my workout, because my arms are dead.