Warning to silk fly line fishermen. Fishing or casting silk fly lines in temperatures near or below the freezing point will damage the finish of your silk fly line. The oil and varnish in the line will stiffen and crack under repeated flexing.

Understandably, I will no longer replace lines that are fished/cast and damaged under these conditions.

~ Olaf Borge

Breaking in, fishing, maintaining, and repairing the finish of silk fly lines

From Olaf Borge of

Silk fly lines were originally designed for bamboo fly rods and they still excel on those rods, but graphite and fiberglass rods can spring to life with the proper silk line as well. Natural silk lines have the Three S’s required of a fly line used on any great fly rod. They are: Soft, Supple, and Skinny.

To enjoy the benefits they provide the fly fisher for fooling selective trout, you'll need to follow a few rules to reap the distinct advantages they offer over synthetic fly lines. Below, I’ll give you some brief pointers on the preparation, care, and attention required for silk fly lines that will help make your silk fishing experience trouble free.

Initial preparation of a new silk fly line

Phoenix Silk Fly Lines; Oil, synthetic varnish finish.
No initial preparation is required except to dress it with Red Tin Mucilin to make it float.

J.P. Thebault Silk Fly Lines; Traditional oil finish
Unroll the line completely, stretch it with your fingers, take some dressing and rub the line so that the product can penetrate the finish. Apply a generous amount. Wind the line back onto the reel. This will surround the line with the rest of the greased line. This procedure is necessary for softening the line. It should be repeated at least 5 to 6 times, with a one-day break between each application, until the line is VERY supple. I provide a sample of a broken-in line with every Thebault I sell.

The coating quickly absorbs the grease; it will swell slightly, so keep a reserve amount of space on the spool. During the break-in of the line, vary the length of line cast. Cast the line gently for a half hour and then let it rest.

Avoid tight loops during false castings. Rather, use a rod with intermediate action and avoid double hauling, the lines profile will permit casting some distances simply by casting slowly and let the rod do the work. One should not, string up the rod by sharply bending the silk tip. Bend the leader butt. These rules are meant to obtain a supple line after polishing. The finish will have hardened, but will have the characteristics of a snake skin; with maximum suppleness and slickness.

Attaching the line to the backing
Attach a short piece soft mono, of the appropriate diameter, With a perfection loop to each end of the line and a loop on the backing large enough to pass the reel spool through will make turning the line around easy, or nail knot the backing to one end of the fly line.

Attaching and designing a leader for a silk fly line
Some people double over the tip of the silk fly line and make a loop. This like a braided loop leaves a big gob at the line leader connection. I attach the leader with a nail knot. The trick with this is using the appropriate diameter and softness monofilament. The diameter, rule of thumb, for all types of fly lines, is the butt of the leader is 2/3's the diameter of the tip of line. Silk lines are small both in the tip and the belly. A Phoenix DT 4 WT has a tip of 0.020 and the belly is less than 0.035. So the belly of this silk fly line is smaller than The tip of any PVC line. Using this rule of thumb, 2/3 the diameter 0.020/3 = 0.0066 x 2 = 0.013. The butt of the leader for the Phoenix Silk Fly Lines should be 0.013. The standard way of building a leader is starting with stiff Mono. ( e.g. Climax). then use softer mono. as you proceed to the tippet. A silk fly line is so supple that, if you use stiff mono at the butt it will, first, be very difficult to tie that nail knot and, second, when the energy of the cast reached the stiff mono in the leader, the casting loop would expand and dissipate some of the casting energy. If you build your own leaders I recommend softer mono like Dai-Riki Velvet, Orvis Super strong, Umpqua or Frog Hair. To adjust your leader to work with a silk fly line, make the diameter reductions similar to the original leader with an 0.019 or 0.021 but you may have to increase the length of each step down to get the length desired. Here is a 9’ modified for silk line George Harvey leader from the butt 0.013/20”; 0.011/20”; 0.009/20”; 0.008/12”; 0.007/18”; 0.006/22”-30”

I have used Dai-Riki Velvet knotless leaders. I buy 15’ leaders with a 3 or 4X tip, I measure the butt diameter until I have the proper size e.g. 0.013 cut the leader at that point and tie it onto my silk fly line. I end up with an 8’ or 9’ leader plus a 12”–20”, 5x or 6x tippet.

I have been experimenting with Frog Hair Knotless leaders. They have a “Soft Butt George Harvey” leader that seem to work well. The butt of the leader is 0.015, which is almost small enough to use with out trimming the leader to size.

Preparing a silk fly line to fish
Do not use any dressing/floatant, that contains silicone, on any silk fly line! First the silk fly line must be dry before applying either Red Mucilin or Thebaults dressing. It doesn’t require a lot of dressing but the dressing must cover the entire surface. I apply three light coats with my fingers or a felt pad. I run the line back and forth on and off the reel, then with the last coat I let the line dry for several minutes and then buff with a shop towel. The dressings are like car wax which Applied in a thin coat and buffed making water bead on the surface. Thebaults dressing and Red Mucilin are Hydrophobic.

Casting a silk fly line
Casting is the same process as casting a PVC line except it takes less energy and force. So relax and slow down your cast!

Maintenance while fishing
If or when your line begins to sink, wipe the line down with a shop towel or chamois. Do not apply dressing to a damp/wet fly line.

Maintenance at the end of the day of fishing.
Remove the wet portion of your line, from your reel, keep it in loose loops until it dries.

End of season care of silk lines.
Remove the line from the reel, clean the line first with paint thinner and then clean the line in soapy (not detergent) water, then in clear water. Let line dry completely, wind the line, in loose loops, and place it in a dry, dark, cool place (not the refrigerator).