I have used only Aurifil invisible thread. It is on a very large cone and I have had no trouble with it. I do use cotton thread, to match the backing, in the bobbin. I really appreciated QuiltNama's comment. I have made several quilts for my 103 year old aunt in a nursing home. I don't think I used invisible thread in any of hers. I will certainly be careful not to use it in the next quilt I make for her.