Q) Sometimes when I am tattooing an outline I notice the needle sometimes sticks in the skin of who I am tattooing. Am I not using the correct amount of power to outline the tattoo?
A) This is usually due to one of two reasons- too much needle, too slow of a stroke cycle (not enough pokes per minute). You are working faster than your machine can keep up, so it hangs up. Sometimes it's as simple as turning up your power a hair, but usually it takes a bit more than that. For lining you are looking for a shorter (therefore faster) machine stroke- that's why some limners are "cut back" with the machine frame altered to keep the contact point close to the hinge end of the armature bar, shortening the stroke length and speeding up the machine. Some machine frames have adjustable binding posts to allow the contact to be moved forward or back, lengthening or shortening the stroke.
A change in stroke length often will need to be accompanied by a change in spring tension... and if you are not experienced tuning machines, this can be a whole ordeal in itself. Be sure to have a few extra backsprings before making any tension adjustments, and if possible, only mess with your machines if you have backup ones in case things go wrong. You can find detailed instructions on adjusting spring tension in the technical chapters of my book Reinventing The Tattoo, available here at this website.
You may also find the hanging up problem to happen when using rotary machines. If you find it happening no matter where you set your power or how much needle you have hanging out, then the problem can only be fixed my going to a more powerful rotary machine, or in some cases a power unit capable of higher voltage. When in doubt, though, turning the power up more and more is not the answer, and can lead to damaged skin.