Hey there! You can bulk with weight machines but free weights are my preference. Either way, it's all about working the muscle hard and then eating enough so that it rebuilds and gets bigger over time. That takes organization and consistency...if you don't have a plan, it's a LOT tougher to see results. I'm going to be doing a program this summer that's all about gaining mass in an efficient and effective way and could really help you out. (bunch of my friends have done it and gained b/w 15-20lbs of muscle) Let me know if you want to know more; happy to discuss.