puckering seams

[lizzieb]

I am working on patio furniture cushions with sunbrella fabric.  Horrible pickers seams I have tried increasing/decreasing pressure, lengthening stitches, and tension adjustments.  Could it be my needle size?  How do you determine what size to use? What do all those numbers /mean?

[sofadoc]

Acrylics can be a little cantankerous with puckers. Steaming the seams can help.

What size thread are you using? What model machine?

For outdoor cushions, I use 92 or 138 poly thread with a 20 ga. needle.

[lizzieb]

I have a Juki 1541s.  Needle size is 18 - I was thinking of going to a 14.  When you look at the holes left from the stitches, they are HUGE. I usually sew vinyl and use 18 or 20.  Not sure what the thread size is.  I can check tomorrow.  I started sewing these with a Chandler which was a lot worse.  I was thinking it might be too much pressure on the presser foot.

[Tejas]

 Here are two links on seam puckering that might help.

http://www.amefird.com/wp-content/uploads/2010/01/Minimizing-Seam-Puckering-2-5-10.pdf

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&sqi=2&ved=0CDMQFjAG&url=http%3A%2F%2Fwww.amann.com%2Ffileadmin%2Fdownload%2Fnaehfaden%2Fb_nahtkraeuseln_EN.pdf&ei=apW2VLmCKYSRyQTVlYDwAQ&usg=AFQjCNGe3qnyYZVuNHJiKuOf6ndJPMtJSA&bvm=bv.83640239,d.aWw

[lizzieb]

Thank you so much for your help.  I will definitely be taking a look to see if I can find the source of the problem.

[bobbin]

Try a #16 needle and #69 or #46 thread (lighter than #69).  Loosen your tensions and check to see of the tensions are still in synch. by stitching through one layer of fabric along the true bias.  Hope this helps.

[Mojo]

I sew 100's of yards of acrylic every week. Puckering on acrylic is most times caused by the sewer. I have puckered my fair share of seams and it was
caused by my feeding technique. Puckering can also be caused by what Bobbin stated, tension. I would start with looking at how your feeding
the fabric. If you have a walking foot or compound machine then allow the machine to do the work. Simply guide the material and be careful how you guide it.

90 % of my puckering problems I created myself by being tired, not paying attention and sewing too fast. In other words I got lazy with my feeding
technique and caused the puckering. If your using polyester thread then steaming will remove the puckering. if your sewing with Solarfix or Tenara, forget it.
It is nearly impossible to remove the puckering with steam or anything else. I have junked my fair share of awnings because of this.

For the record, I use 18 ga needles with 2000 Solarfix ( 138 thread ).

Chris