Crochet thread
 

I have purchased number 3 crochet thread to tie the quilt I am making. Should I double the thread?

I think it is really your choice. I have a baby quilt that was made for my late DH. It is a GFG and was tied with very thin crochet thread. The fabric is beginning to fall apart, but the ties are still fine.

I would suggest trying it both ways and see what you like best.

I would'nt think you would need to, I have seen baby quilts tied with embroidery floss, and it worked great.

It just depends on the look you want. I saw a really cute one tied with red that looked like they used 3 strands. Gave it a sort of starburst type effect. Had not seen one done that way before. Usually it is just the single strand and it is sufficient, so however you want to do it.