I always sew mine together now.. I used to tie them with elastic, but it was hard to get them even and they could pull out easily.
I use regular thread but I double it so its strong. It's kinda hard to get through the second time around, but i just push the needle down with my hard wood table..lol.. and presto! a beautiful even korker bow!
I also hot glue the back where I finished the stitch anyway, so I know it's not going to come out.