I rethread for a few local jewelers in my area. I have a string of black diamonds to rethread and they are already on a cotton strand. I normally use Silkon but the #1 is too thick. Do you have a #0 or a different thread small enough to fit through? Thank you.
A good alternative may be Berkley® FireLine® 1- or 2-pound test thread. This thread is extremely thin and can be used with a very fine beading needle. It's very strong, resists abrasion and is UV protected, so holds up well to sun damage. This type of thread is slightly stiffer than the Silkon® you've been using, however it still creates a nice drape with strung beads.