The nylon melts, the poly does not. The nylon is unruly, like fishing line, the poly is much softer and finer.

I bought some once and then read about it and never did not use it after reading bad reviews.

It can be snarly and unruly in the bobbin, but you can still use it on the top. I did not know you were not "supposed" to use it in the bobbin and I did when I was first learning to do FMQ and it was fine, well behaved even.

If you use poly invisible thread in the top, you have to use a very loose tension. No higher then a 3. Same with metallic threads. I use a 0 setting. If you can control the winding tension on your bobbin, wind it loose. The Sidewinder bobbin winder has a tension adjustment knob that is very handy.

I have used poly invisible thread and had no problems, but only on the top. I have never used it in the bobbin.

Invisafil may be an alternative. It's 100wt poly, and almost disappears. I've found it very well behaved and use it all the time for machine stitched bindings. I think it comes in about 15 colors, but it's so fine you just have to get close, not match.

--Heidi

http://www.hugstitches.com

http://www.flickr.com/photos/32113973@N05/

I have used YLI nylon filament thread (very fine, .003mm I think) in the bobbin of my Bernina with no problems. I do wind the bobbins slowly, with little tension, so it doesn't stretch. It is also advisable to use metal bobbins with it; plastic bobbins can distort. You never want to overfill a bobbin with this thread either; it's best to slightly underfill.

Right Rabbit2be! If you are looking for a new thread try the InvisaFil. It sews as nice as the YLI silk thread for a much better price. There are new ways to manufacture thread now, that poly isn't the old poly from years ago. The idea that only cotton thread is the best is not true anymore.

i've used it 2x. once very unsuccessfully and once it was okay. but in both cases wherever you stop and start, you end up with a tiny pokey end that itches like mad unless you manually leave a long tail and sew every end back through the top and batting. what a pain. i used top-quality ultra fine poly and it took forever to adjust the tension and then to get it back to normal. imo, not worth the trouble.

oh, (BIG OH!) it is IMPOSSIBLE to see it to thread it!

I had the same threading problems as butterfly wing. Neither of my rather aged machines like it and I iron everything (teatowels included) so I haven't persisted.