Listen to Vince - he is right on. I use 3M fine line to mask off where I am going to shoot paint - it leaves a razor sharp line like exactly like Vince says. I just sprayed a 1/3 scale with dope over koverall - you would expect bleeding with cloth but not with the 3M fine line. I did red/white/blue and did not have anything but sharp lines. Once the fine line is on, I use 3M blue paper to for all the rest of my masking - I run it down the middle of the fine line and then attach my paper to that - and again using 3M blue to seal everything. After spending hour and $$ to get to this point, there is no sense in saving a few $$ to only have to fix it.

Dan