I use Aurifil monofilament thread on almost every quilt I do FMQ on. I have a Bernina Artista 200 and have never had any trouble. I use cotton Aurifil in the bobbin in a color that matches my backing. When I get better at FMQ, I may give up my monofilament thread; but, for now, it works great for me. I think Aurifil's monofilament is made from nylon.

I won't use it any more. I read on this board a long time ago that if it leaves a loop that a baby's toe or finger can get caught in it and cause problems. I have grandchildren so I will not take the chance.

Have you ever used Bottom Line? It is great! Blends into the fabric nicely. I always use it in the bobbin when machine quilting and often as the top thread if I don't want it to "show" as much. Wonderful thread!

I am using it on the top only..... with a buttonhole stitch to hold down applique.... I have moved my tension all over the place and still the bobbin thread show through... any more suggestions????

Have you tightened your bobbin tension and lowered your top tension? You may need to do both. What is your top tension setting at right now? Have you tried putting it down as far as it will go?

I don't like the feel of monofilament thread so I don't use it.

the only tension setting I have is on top and set at 1..... I have a Bernina activa 230.

You can still adjust the bobbin tension. Your bobbin case has a hole in the finger. If you thread your bobbin thread through that finger before placing the case in the machine, that will tighten the bobbin tension slightly. If that is not enough, you can use a tiny screwdriver to tighten the screw on the bobbin case spring. Here is a link to a Threads tutorial on how to adjust that screw, but there are others on the net:
http://www.threadsmagazine.com/item/...nsion/page/all

It's a good idea to do the adjustment while the bobbin case is inside a baggie. I have loosened the screw so much it fell out! This screw is tiny and hard to find if not inside a baggie. It is generally recommended to tighten or loosen this screw in just quarter-turn increments, as it does not take much to change the tension. It's still a good idea to Google "how to adjust bobbin tension in a sewing machine" and read several tutorials before doing this yourself. Some people are so afraid they will not be able to get the bobbin tension back to where it was when they started, they buy an extra bobbin case. One is used for regular sewing and never gets its tension changed; the other is for experimentation with different threads. A dot of fingernail polish on the extra case lets you tell them apart easily.

One more thing about your monofilament. What brand are you using? And how are you feeding it to your machine? Nowadays when I use monofilament for machine applique, I use my Superior Thread stand (along with a thread net) to provide very nice, even thread flow without resistance to my machine. Here's a link to the thread stand I love:
http://www.superiorthreads.com/shop/...thread-holder/

However, from your description of the issue, it seems much more likely that your bobbin thread needs more tension on it.

thanks ladies.....