Super versatile spider web pattern is available for free on my blog http://faerieringscrochet.blogspot.com
I used black crochet thread and silver crochet thread to make my webs. How much yarn you use depends on how big you make your web. Just keep adding more rows to make your spider web bigger and bigger.
Video tutorial is also available at https://www.youtube.com/watch?v=p6EdgKerW14