It is a 40 wt thread so may be a littler heavier than what you are used to. Also it has a tendency to be pretty slippery so your seams may come apart easily at the beginning and end of a unit. Personally, I would only recommend it for quilting or machine embroidery or machine applique where you want the stitches to stand out. Additionally I don't know how hot your iron is. The thread is not intended to be exposed to the high heats that some people press at so you could possibly melt it if you press your blocks with uber high heat and steam. That said, I piece with Superior bottom line in my bobbin all the time (also a poly) and have never had an issue but I do not use steam, only a dry iron when piecing. If it is a nice neutral color I would save it for quilting only.
Last edited by feline fanatic; 06-21-2015 at 09:19 AM.