Does anyone know if theres a trick to sewing thick elastic with an industrial sewing machine?

Question

I can sew anything with my machine, leather canvas, nylon webbing, but when it comes to elastic the stitching puckers at the back, I have tried everything it puckers everytime. I regularly have to sew thick elastic inside two layers af nylon webbing or leather, the machine will sew the two layers perfectly until i put the elastic between them.

Answer 1

The rubber in the elastic is not moving correctly through the feed dogs.  One idea is not to PULL the elastic too hard when sewing, and I put tissue paper over and under the elastic when I sew, then it moves smoothly through the machine. After sewing simply tear away the paper... GENTLY.

Answer 2

I'm thinking there might be an issue with the thickness of the elastic, that the change in the thickness might be throwing the needle tension off a bit. I'm sure you've tried all these already, but here are a few things i try when my machine and what it's sewing get into arguments. Can you use a longer stitch?  Sometimes a longer stitch is needed to go through thicker layers.  can you reduce the pressure on the presser foot?  Sometimes reducing the pressure helps to feed difficult fabrics, you might need to loosen it when stitching the elastic.  Are you using a thick enough needle?  Changing to a thicker needle might help.  Are you using a cutting point needle or a sharp?  Perhaps a different needle point might help.  Is the stitch balanced, is the lock in the middle of the fabric layers or is the bobbin being pulled too far up, causing the puckers?  You might need to adjust the needle tension when you stitch the elastic.  You might need to adjust the tension in the bobbin case for when elastic is sewn.  Or you might need to switch to an elastic with a thinner profile.  I realize that some heavy duty applications need the thicker elastics for durability, so I understand that might not be an option.   It could simply be the spongieness of the fibers the elastic is made of, some elastics are quite thick and spongy and made of soft wooly nylons and polyesters for maximum softness and stretch, while others are made with firmly woven and knit  fibers to prevent rolling and to add firmness to locations such as waist bands and upper edges of some bags.  Perhaps a different elastic might work better.

That's the best i can come up with, perhaps searching Yahoo groups for a group for user and repair people of machines might also help. There are a few groups with sewing machine specialists who might have a few more ideas.