I'm working on some pullover nylon windbreakers and 'coaches' jackets. Image is 6.75" Maltese cross for firedept. I've got 1 layer 2 oz cutaway underneath, and started out at 6 on MT, have moved it gradually up to 10. Problem is that the stitching seems to be 'separating' or splitting the nylon-worse inbetween the upright 'bars' on the fire hydrant, and around letters-you can see the nylon has separated and the white liner is showing through. If I go to higher (11) MT, it almost is gone, but then phantom 'bobbin' breaks occur frequently even though it doesn't break. Trying one now with solvy on top to see if that helps prevent it-have 9 more to go. Then we have to add names on front. Already did front left with a 3" maltese cross, and this problem didn't show at all! Help! Roland