What number is satin stitch on Piaf quilt expressions 4.0

https://www.performancesewing.com/partsdatabase/instruction-books/pfaff-2034-2046-manual.htm

For sale at link above.

Free online manuals for other models if you use Https://www.google.com to search.

If you are free motion quilting, you are manually moving the fabric while the machine stitches. You are either moving the fabric too slowly or the machine speed is too high. To get good FMQ results, you need to find the sweet spot where your hand movement equals the machine speed. FWIW, stitching with monofilament thread is difficult. You may try it with regular thread and see if the result is better.

Unable to locate a manual for the machine you listed. However, you can usually make your own basting stitch by setting the stitch length as long as possible, stitch width to zero, and loosen the top tension.

A satin stitch is a combination of a wide zig-zag and a short stitch length. Set the stitch width to the maximum. Then while stitching, shorten the stitch length until the threads lay next to each other so no fabric shows between the threads but the threads do not overlap. It would help if you have a satin stitch foot so there is space under the presser foot for the extra threads.

Sewing Perfect Satin Stitch Wildly Wonderful Wearables Patterns Notions...

Satin Stitch or Zig Zag Machine Applique stitch

Machine Appliqu Basics 1 Turning right angle corners with satin stitch

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Thread tension in this machine is set electronically to vary by type of stitch. There is also an alert light pertaining to the bobbin.

Getting The Quilt Expression 4 2 Ready For The Test Drive

Sewing

The first link also offers a further link to an online guide. That said, as the tension is electronically controlled and if any sort of fine tuning is required, that would likely require a trip to a service center. Hopefully, one of the videos provided by the links above will be helpful

A nice satin stitch is set when the zig-zag threads touch but do not overlap the previous stitch. It is a matter of finely manipulating the stitch length to accomplish this goal.

Sewing Perfect Satin Stitch Wildly Wonderful Wearables Patterns Notions...

How to Sew Satin Stitch

How to Do Satin Stitches on Regular Sewing Machine

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0ahUKEwiV_b7QwsLTAhVQ7WMKHRSfBbAQFghyMAc&url=http%3A%2F%2Fmachinequilting.mqumag.com%2Fwp-content%2Fuploads%2F2014%2F12%2FSatin-Stitch-Techniques-Part-1.pdf&usg=AFQjCNFXYKp2C-RJEAAUMWwApqZlU895uQ&cad=rja

You could use an applique (satin) stitch freehand on your machine. But, it takes some practice with steady hands to get it to look nice.

In the video, she uses a heat bonded stabilizer. If you don't use a bonded stabilizer, you'd want to put the fabric and stabilizer in a hoop to keep the fabric tight. If you are going to manipulate the fabric manually, you also would drop the feed dogs.

Machine Applique Tutorial

Tips for Machine Appliqu

Sewing Perfect Satin Stitch Wildly Wonderful Wearables Patterns Notions...

How to Monogram with Basic Sewing Machine (in this video, she turns the fabric while stitching but to get a nice letter, you can try not turning the fabric to go around curves)

How to embroider on home sewing machine (she manually manipulates the fabric, uses a free motion quilting foot, drops the feed dogs, and uses stabilizer and a hoop)

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have you tried changing the needle?
have you tried adjusting the top tension?

As a general rule of thumb, satin stitch is obtained by selecting zig-zag, turning stitch width up to 3 or 4 and stitch length to 0.5. If you have a clear plastic open toe sewing foot, put that on to help view the area.

If you are doing applique (attaching pieces of fabric to another surface) with a satin stitch, you may also need to use tear away stabiliser underneath or interface the fabric first, it depends on what/where you are doing the satin stitch onto.

And a nice machine embroidery thread will give you a much silkier appearance than plain thread.

Try using the zig-zag setting, but adjust the stitch length to .3 or .4 (very small).
good luck!