Knotting monofilament has always been beset with problems and, as the success of the day relies on secure knots, we’ve got to know what we’re doing when forming our joints.

The construction and tightening of any knot in any monofilament creates a large quantity of friction and because nylon monofilament is a poor conductor of heat, the destructive high temperatures produced are restricted to the immediate area around the knot. The molecular structure is severely attacked, reducing the breaking strain.

The age-old advice to wet the monofilament with saliva is still the best counsel. Well moistened monofilament, when knotted, should be secure against critical strength loss.

Although fluorocarbon is UV light resistant, it’s no bad thing to get into the habit of storing all your leader material in cool, dry and dark conditions.

There is a belief that mono-filament which has become wet will, even if dried out, suffer a catastrophic reduction in strength. Bog-standard monofilament, due to its water absorption properties can suffer loss in strength, but modern co-polymers and fluorocarbons do not absorb water at all and can be safely soaked and dried out without compromising strength.

Fluorocarbon is so resistant to destruction that the stuff we throw away today will still be about when we are all gone. So, we should take great care in the disposal of it.
Without going into the highly complicated technical detail, co-polymer nylon is prone to twist and, after the capture of a few fish, will be altered to such an extent that it may become visible to fish. It is advisable to change co-polymer leaders throughout the day, especially if reduction in sport is noticed after a number of fish have been taken. Mind you, it is good practice to change your leader, regardless of type, if for no other apparent reason catch rates drop.

Strategic use of monofilament types
Although it is common practice for anglers to use one type for all techniques, this is not advisable. One of the best things that choice in monofilament types can do for modern fly fishermen is to allow them to tailor leaders to perfectly suit tactics.

Nylon monofilament is still the leader material of choice for the bulk of salmon anglers and wet fly pullers for wild trout. It has a high stretch capacity, has only slightly negative buoyancy and suits shallow water fishing for feisty fish held on a short line. However, low knot strength and susceptibility to abrasion can have anglers searching for alternatives.

Co-polymer monofilament is very suitable for Nymph and Buzzer fishing in shallow water, but excels as dry fly leader material. Dry flies which sit well down in the surface film require little encouragement to sink entirely. In such a situation the mere effect of ripple acting on the leader material will sink the fly, so it makes sense to use a material which has a slow sink rate.

The high knot-strength and supple qualities of co-polymer monofilament also allow finer leader materials to be used, either for ‘educated fish’ or when very small flies are required.

Top quality co-polymers are now the choice of cost conscious anglers wanting a leader material which has all-round compatibility.

Fishing is a very subjective sport and one man’s meat can definitely be another’s poison. Just as we have favourite flies in which we invest magical properties, our choice of monofilament may well transcend logic. My personal favourites (at the moment) are Stroft GTM in co-polymer, and Riverge Grande Max and Sightfree G3 in fluorocarbon.

As regards colour, you will find that most well-informed pundits will advise clear monofilament. Most monofilaments have a low refractive index (fluorocarbon the lowest of all) which simply means they are virtually invisible in water. To add colour to a monofilament simply raises the refractive index and, by the same token, visibility. Similarly, matt finished mono is a ridiculous concept dreamt up by someone who didn’t know Shrove Tuesday from Sheffield Wednesday. Glad to see that that one has at last fallen by the wayside.