Make an array without separation/line showing between I need help figuring out how to model something and use an array with it on the Z axis so it repeats smoothly.. 
It doesn't seem to do what i want when I apply a glass material.
I can't seem to figure it out exactly but any help would be appreciated, thanks.
You can try enabling "merge" in the modifiers panel.



You can also try "first last", which will merge vertices from the first object and the last object in the array. (A circle for example.)

Make sure you set the merge distance.



Hope this helps you out.