Choosing Fly Tying Thread

Choosing the right thread will make tying easier and produce more durable and attractive flies. Modern fly tying threads are usually constructed of either nylon or polyester and have been waxed for ease of tying.

Ultra Thread is an extra strong waxed nylon thread with a slight twist that helps in securing materials to the hook. It wraps flat with minimal thread build up and comes off the bobbin very smoothly. It is an excellent thread for tyers of all skill levels and is available in 4 sizes to meet all fly tying needs.

Size – The textile industry standard for measuring thread is referred to as a denier. Denier is the measured mass in grams of 9,000 meters of thread. For example, if the mass of thread is 70 grams, it is considered a 70 denier thread. A 140 denier thread has twice the mass of the 70 and, therefore, is larger and stronger.

Color – Most color choice is a personal preference. Since the thread usually only shows up on the head of a finished fly, all you need to do is determine the color you would like the head to be. On thinly dressed flies, the thread color influences the color of the fly when wet. Use this to your advantage by choosing thread colors that give you the color hue you desire for the fly. When in doubt, stick to one of the 6 most popular colors: Black, White, Olive, Gray, Tan, and Red.
Ultra Thread is available in 4 sizes and and a wide range of colors.

UTC 70 label UTC 140 label UTC 210 label UTC 280 label
70 Denier
Ideal for dry flies, nymphs and midges. Best on size 14 – 32 hooks. Breaking strength is approximately 1 lb.
140 Denier
The ideal size for all but the smallest trout flies as well as small streamers and bass flies. Best on size 6 – 14 hooks. Breaking strength is approximately 2 lbs.
210 Denier
Designed specifically for the largest trout flies as well as bass and saltwater flies. Best on size 1/0 – 8 hooks. Breaking strength is approximately 3 lbs. Excellent for spinning deer hair.
280 Denier
Made for the largest bass and saltwater flies and any fly where you need to quicky build up a thread body. Best on size 6/0 – 2 hooks. Breaking strength is approximately 4 lbs.
70 Denier Fly 140 Denier Fly 210 Denier Fly 280 Denier Fly