I use Superior Poly Invisible Thread a lot on my table runners. I also use it in my bobbin. I have ironed with a hot iron and have never had it melt. I wind the bobbin very slowly and have no problems using it both in the top thread and bobbin thread. My needle threader does not work, like Rhonda K says, but I just hand thread the needle like she does. I love this thread. I use 2 colors - I use the darker one on darker fabrics and the clear or lighter one on light fabrics. If I have both light and dark fabrics, I have found that the clear works best.