Various reasons I haven't fished much. But I made a floating leader out of Coats and Clark green thread from Wal-Mart.

I soaked it in a silicone liquid. There is a spray can with an orange top at Wal-Mart in the sporting goods section. It is for spraying and waterproofing leather boots and shoes and such. I sprayed it into a contaier until I got enough liquid to soak the leader. Let it set overnight. Hung it out to dry the next day. The fellow I sent it to said he fished a very rough raging river....or something like that....Anyway he said it floated all day.
Jim