Looking to combine two lengths (3x9) of PU Coated Ripstop to create a 6x9 tarp. Concern is the best way to maximize the center seam strength with the strongest sewing technique. I've heard of a "felled seam" (http://sewing.about.com/od/techniques/ss/flatfelled.htm), but it looks a bit involved, and I'm not sure the machine will tolerate the thickness of the coated material. how do the DIY'ers solve the strength issue?
Looking forward to hearing various successes!