zski wrote on Apr 3^rd, 2012 at 7:40pm:

In an attempt to be thrify I once tried to backfill a spool of Fireline with a cheaper line but couldn't get a blood knot to work so gave up...

I consider backfilling about two layers of mono onto the spool a necessity to prevent fireline and similar lines from spinning on a smooth metal spool. More than once I have had to perform "field repairs" on other peoples reels to correct this problem. Use back to back uni knots or blood knots to connect dissimilar fishing line. They are tricky to tie correctly the first time but help yourself by doing it in a well lit spot at a desk or work bench not in the field.