Originally Posted by loopywren
I was taught not to know but I do with quilting by hand, I use a fine cotton thread and find it doesn't bulk up at all, in fact doing several stitches on the spot to secure is more bulky. I pull the know through so it doesn't show. You should do what you are comfortable with. As for the blocks you have now, why don't you wash one and see how it goes.
Good suggestion -- I might try that. If the stitching comes loose, I can always sew it again.