I use Superior MonoPoly but from various 820/830 forums many of these specialty threads need special (of course) settings to work properly. Here are some tips that worked for me. I don't use monofilament in the bobbin--yet.
I am using a 60wt thread in the bobbin. Thread the bobbin as for embroidery. Since the 820 doesn't have an embroidery module, I suppose that mean tighter than "normal." Otherwise the top tension, no matter how loose it is set, will bring the bobbin thread to the top. This is especially apparent as one turns curves and corners during free motion.
Slow your speed. It seems that works for monopoly as well as metallics.
I find that a titanium needle does reduce shredding and breaking significantly.
Use a thread net on a cone. I personally find that my 830 sensors do not "like" threads that are springy as they enter into the machine. I use a free standing guide for cones, then the set up for bobbin winding (the two guides linked together) and then into the threading channel.
As you thread, hold the monofilament (or metallic) with your right hand to put a little tension on the thread and guide the thread along the channel onto the auto threader and into the cutter. The object is to get the thread as straight as possible. It will probably spring out of the needle during auto thread but just thread the needle manually.
It sounds pretty complicated as written, but once you get the motion down, it becomes 2nd nature.
Hope these tips work for you too. Libbi
PS: Join the Yahoo Group Bernina Series 8, lots and lots of good info
Looking out the window at Lake Leman in beautiful Switzerland
I've seen the end result of using Invisifil thread (100 wt.) for quilting and it can be beautiful. However, my Bernina 820 doesn't like any of the combinations of needle size, needle type, or top tension that I have used; and I've tried a bunch. My thread breaks and/or shreads. Sometimes the stitching puckers. Has anyone been successful with this thread (used in the bobbin and on top), on the Bernina 820 or 830?
Thanks for any help - Bonnie