I bought the 30" sheeter and received it last Weds. I have run a number of things through it on 24" premask, I am using Rtape Conform series premask. The things I have masked run from 3' to 10' long and everything that I have done has a lot of tunneling in it. I called the company and their suggestion to start with was to not use the crank and to pull the material out and up not letting it droop down at all, I did this and still have the exact same problem. I have it in my basement and it is a little cool and a little humid down here could that be my problem? I know that several of you have the sheeter and have made it past the learning curve, any suggestions to get me past it.