DD,

My wife has made three silnylon tarps for me, two 10X10 and one 8X10. The center seams are about 3/8 to 1/2 inch flat felled and the edges are about 3/8 inch rolled. The seams are not taped. The tie outs are 5/8 or 3/4 inch grosgrain ribbon sandwiched between the tarp body and small tabs of silnylon to reinforce the stitching. I bought nylon thread, but it was too heavy for her machine, so she used cotton coated polyester thread. To seal the stitching, I dissolved 100 percent silicone windshield sealant in Coleman fuel and painted it on until the threads were saturated. When the solvent evaporates the silicone is left behind in the thread and needle holes. They have not leaked yet. I don't think you can have too many tie outs so she put on a lot of them. I have even had her add more along the center seam that were not originally there.  They have stood up to those crazy prolonged winds in Quetico on several trips now with no signs of weakness. The attached picture was taken July 2008 on McAree during one of those two day blows. 

Pat

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