Aurifil’s 100% Cotton 12wt thread is the heaviest weight thread made by Aurifil.  It's perfect for hand applique, hand embroidery, hand quilting, cross stitch, embellishment, handmade lace, machine applique, blanket stitch, machine embroidery (especially for designs that use a longer stitch length), machine art quilting, Sashiko, redwork, lower looper serging, and longarm quilting. 

Needle recommendation:  90/14 or 100/16.  Use a thinner weight thread like a 40wt in the bobbin.