Hello Nicola,
Invisible thread is usually like a nylon line and is not easy to sew with, you will have to fiddle around with the tensions until you get the stitches right.
ken
drivewithken
May 2009
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix sewing machines.