I asked about this, David said I should test it,… me and my big mouth…
Silnylon, hem it (fold 1/4 inch twice and 1 row of stitches), 1/2 inch grosgrain, on one side do a zigzag with 1 mm stitch length so there was about 2 mm between holes in the silnylon:
on the other side do a bar tack with about 1/4 mm stitch length so there was about 1/2 mm between holes in the silnylon:
suspend 25 pound lead brick. didn't break so put a little more weight, maybe 30 pounds, ripped:
The fabric ripped where the bottom edge of the zigzag seam was. I would have expected that the bar tack ripped at that location, not the looser zigzag.
Maybe the fabric just happened to be weaker there?
Maybe with the bar tack, there are more threads that distributed the load.
The close needle holes of the bar tack didn't seem to weaken the fabric which is what I thought.
I guess I'll do bar tacks from now on.
I don't think it made any difference that I sewed through three layers of fabric in the hem, could just as easily have sewed to the fabric through one layer above the hem.
