Quote Originally Posted by Sewbee View Post
Invisible thread has its pros and cons. I would use only POLYESTER invisible thread, not nylon for the reasons already mentioned. Nylon tends to be more brittle, yellows and will melt when pressed with high heat. Poly is more durable and flexible and can withstand the heat of pressing. If you are having trouble staying in the "ditch" try using an Edge Joining Foot which is what Cathy F described above. Here is a pic:

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Just keep the middle blade in the ditch as you stitch and the needle will follow along right behind that line.

stead.

Invisible thread usually comes in clear or smoke colored thread. Use the smoke for dark background fabrics and the clear for lighter fabrics. It is very hard to handle and wind on the bobbin but it does have some uses. As you get better at doing stitch in the ditch you may find it is easier and looks just as good to use a finer weight neutral color thread like Bottomline 60WT thread on the top. This thread is great in both the bobbin and top needle and comes in both neutral and many colors to coordinate with your fabrics so it blends in very well even if you get out of the ditch from time to time.
I have that foot and used it today...and with all the negative possibilities...I think I'll just skip the invisible thread and stick with this foot. I have many places that I STID with this foot, that literally I had to pull the seam apart to see the stitching so it does work well....just needs practice!