I learned the hard way that clear "invisible" thread does not play nicely in the bobbin. Having said that, I have no problems using it on top. The trick is to set the top tension to Zero or almost zero and to use a neutral in the bobbin. Also, set the spool of invisible thread upright and wind it off the spool that way, rather than let it come off the top of the spool. This keeps the thread from stretching too much before it goes through the rest of the threading process to the needle ( make sure you have a felt disk under the spool to prevent back spin). Good luck.