Hi there. I'm sewing with heavy duty quilter thread and medium weight interfacing for the first time, making a basic tote. Tonight I tried sewing the side pieces (1 layer of regular weight cotton, 1 layer of interfacing) to the front (same, 1 layer of fabric, 1 layer of interface), so essentially I was sewing through four layers. The machine didn't burn out, the thread didn't break, I got through the whole seam...but then I took the piece out and the stitching was ridiculous. It looked fine, clean and neat on the front, and the back just looked like a row of loose loops. I was able to basically pull the seam apart with the slightest tug.
Has anyone seen this? Does this mean my machine can't handle this?
I'm ticked of because I wanted to finish this for work on monday. Shoot.