vorhis Weighting_a_Nymph

weighted nymph 01__Lead_Weight_on_Hook_Shank
Lead Weight on Hook Shank

Guest Blogger: Michael Vorhis, Fly Fisher & Author, FreeFlight Publishing

We all know that key to nymphing for trout is getting the fly to the right depth; more often than not that means close to the bottom. It can be a challenge where depths vary, pocket to pocket and from the head of a run to its tail, and the method of suspending below some kind of floating indicator is not good at letting a fly hug bottom across varying depths. Weight works better for that, but it too has its drawbacks, especially in swift current where drifts can go a long distance before the desired depth is reached. So we add more of it, and we do that in a variety of ways.

Myself, I don’t care so much for bead heads on flies. I know people catch plenty of fish on bead-heads, but…well, I guess those flies may catch fish but don’t “catch” me. The beads are usually shiny little globes and I’ve never seen a larval insect with a shiny globe head. Trout seem to have the ability to ignore that unnatural feature, but my eccentric attitude is often that I’d rather not introduce any source of doubt at all. I use small lead shot on the leader, which I don’t love either but at least it doesn’t alter the look of a fly. What I like best is to add weight to a nymph’s body at the vise, via heavy wire of some kind. It usually introduces at least half the amount of weight I need (and more than a bead-head would), reducing my split shot to a very small amount.

weighted nymph 02__Lead_Weight_Tied_Down_on_Hook_Shank
Lead Weight Tied Down on Hook Shank

The smallest solid lead wire I can find (barring electronics solder which is usually hollow, so lighter) has a diameter of 0.010 inch. (By the way I may be wrong but I do NOT believe that lead wire is detrimental to our streams; like automotive battery terminals, the surface of fishing weights almost instantly becomes the non-toxic, inert substance known as lead oxide, which hurts nothing and no one. The overreactions against the use of lead are more knee-jerk and more ignorantly / social-activistically political than they are scientific. (I salute J.Stockard for not falling for the baseless hoopla and for continuing to provide lead wire for tying flies.) A 0.010 inch diameter is thin enough to wind around hook shanks as small as #18 for nymph thorax areas…and I can wrap in a thin straight bit of such lead wire linearly along the shank on hooks even smaller than that.

But recently I saw, and purchased, some of that new “Tungsten Thread,” to assess whether it’s a superior material for adding weight to any fly. It’s actually very thin tungsten wire, and appears exceedingly strong, so it can be wrapped and even tied in a knot like thread. There are several things I wanted to determine:

  • Workability as compared to lead wire
  • Weight by length as compared to lead wire
  • Weight by thickness (“build-up” on a hook shank) as compared to lead wire
  • Use case opportunities as compared to lead wire


I acquired and tested the larger of the two sizes, which is called “fine.” It’s practically invisible, so I cannot imagine ever in my life needing the smaller of the two sizes unless I were to tie up a size 60 fly, which isn’t going to happen. The size I tested already looks like a human hair. It’s much more “springy” than lead wire, which means you must take your thread and nail down the starting end, wrap onto the hook, and then nail down the other end as well. Lead, by contrast, is so malleable it can be wrapped with bare fingers and released on every turn; it will stay exactly where it’s at. It can be pinched off with a fingernail and it won’t damage the fine edge of my tying scissors either (whereas I’d NEVER cut the much harder tungsten wire with any scissors I didn’t want to ruin in short order). I find lead so joyfully easy to work with…but the tungsten wire is quite usable too if you keep it tensioned and wrap it down with thread, and if you use true wire nippers to cut it.

The tungsten wire’s forte is its incredible thinness, period. And that goes to the question of workability too; you can apply a layer so unobtrusive your fly’s shape won’t change at all. You can think of your weight-adding exercise as “doubling the thickness of the hook’s steel,” or even less. If an application calls for that tiny amount of added weight, this stuff lets you do it.

Relative Weight

This question addresses the “which is better to use if I could use either one?” question. Given that I’d bought some to use and keep, I didn’t want to unspool a bunch of the stuff and weigh it, because I might never get it back on the spool–again it’s fine as hair and has a “springiness” to it. So I made some estimates, measurements and calculations, like so:

  • “Fine” Tungsten wire:  0.0035″ diameter, per my micrometer
  • Soft 0.010″ Lead wire: 0.010″ diameter, (about 3x the tungsten’s thickness)
  • “Fine” Tungsten wire:  9.0 grams per 25yd spool, including the spool…per a fine scale I have access to at work
  • Soft 0.010″ Lead wire: 17.0 grams per spool of undisclosed length

…so I had to figure out the length of the lead wire. I looked up the specific weight and put a stake in the ground: 36 inches (one yard) of round lead wire has a volume = 0.00283 cubic inches. That volume, per accepted properties of pure lead, has a weight = 0.52599 grams. So a yard of my lead wire should weigh 0.52599 grams, if it were 100% pure.

The 17-gram spool I weighed includes both wire weight and spool weight. I VERY ROUGHLY estimated the spool’s weight at about 4.5 grams. If that was right, then the lead wire itself weighed about 12.5 grams. Assuming I was on track, this means a spool of lead wire is about [(12.5)/0.52599] yards long (i.e., about 24 yards long). So I assumed 25 yards, same as the tunsten wire’s one-spool length. Given how companies package and market things, I think that’s a fair assumption. (And it lends some credence to my calcs thus far.)

Then…must subtract the spool weight from the tungsten wire’s measured weight too…I went with the same rough guess of 4.5 grams. So I was left with:

  •  25 yards of 0.010 lead wire weighs about 12.5 grams
  • 25 yards of fine tungsten wire weighs about 4.5 grams

So the lead wire, per length, appeared to be about 2.75 times the weight of the tungsten. Given the roughness of my estimates and the fact that the tungsten’s spool looked just a smidge larger than the lead’s, I roughed my weight conclusions in as:

  •  By length, the lead’s weight is about 3x the tungsten’s weight

And remember that the lead wire’s diameter is 3x that of the tungsten’s. This means that the two materials, by volume (i.e., by “build-up” on a hook shank) will weigh ABOUT THE SAME. (I’m sure they’re both alloys rather than being 100% pure, so the weight similarity isn’t that hard to believe.) So: If I add lead wire to one fly and fine tungsten wire to another (wrapped to the same thickness around the shank), they should sink at very similar rates.

Use Cases

The above approximations suggest that the advantage of the fine tungsten wire is not so much the weight per volume, but the amount of volume that can be used. With the lead wire, you have no choice but to build up some amount of volume. 0.010 is small but it’s not like a human hair. Probably has little use on #22 flies unless they have 3x-long shanks, and probably can’t be used on the abdomen portion of most #20 or #18 flies either.

The fine tungsten wire can be used in those cases, to add a little more weight. Again, it might be akin to adding (up to) the weight of an extra hook to a fly.

 Sources of Error

My calculations are very rough! Sources of error include:

  1. I estimated the weight of the empty spools by weighing a full floss spool and cutting that weight by a third. Very rough estimate. And I assumed the spools of both wires were almost identical. (The spool weight estimate has the potential of being the biggest source of error in my calculations, depending on how accurate my guess was.)
  2. I could find no data on the length of the lead wire, so I calculated it ASSUMING it is pure lead. I calculated the volume per yard, weighed the spool, then rounded to 25 yards (that much is probably a good assumption).
  3. I did not apply a micrometer across a sampling of points on the wires; I just measure two or three times on a single piece of wire and assumed the diameters are consistent or average out to the measurements I took.
  4. I took for granted that the tungsten wire length was as labelled (probably a good assumption).
  5. My digital scale senses fractions of a gram, but I have no idea how much error is in those low-gram measurements; this scale is typically used to measure objects weighing 50 grams to 200 grams, so 5 or 10 grams might be well out of its sweet spot. Plus it’s a work device, used by a number of engineers and not guarded or regularly calibrated as far as I know. (This source of error could be substantial as well.)

I did put an inch of each wire on a tiny “teeter-totter” made from a very thin/light toothpick carefully balanced on the edge of a knife; I fastened the bits of wire to each end of the stick with a minuscule speck of glue. The balance point after the wire was applied roughly confirmed my assumptions about weight by length, which corroborates my weight by volume conclusions to the same degree.

Final Thoughts

I’ll use the tungsten wire for the very tiniest of needs. Given my eyes and clumsy fingers, that’s likely to be sparing use. Lead is so forgiving and so easy to work with, even down to #20 hooks that have longer shanks, that I’ll still tend to reach for it first. (And for #12 hooks I’ll add 0.015 lead.) But make no mistake: the tungsten thrTad is very interesting stuff, enables things the lead can’t do, and I’m glad I have a couple of spools of it.

NOTE from J. Stockard: Michael Vorhis is the author of ARCHANGEL suspense thriller…which has some fly fishing in it…and of adventure thriller OPEN DISTANCE, based on aviation and the deep sea.


  1. Michael,
    Interesting analysis, but begs the question: Is any one weighting method more or less effective when it comes to actually catching fish? All personal preferences aside, the case against lead as a toxin in the environmental seems to have been well made from the science standpoint. Of course, such is not the case for the bureaucrats who implement bans and other silly regulations. When I use wire for weight, I use lead-free wire in all my flies for the simple reason that any lead fishing tackle is banned in Yellowstone and Glacier National Parks. Even through lead isn’t banned, but merely recommended against by Montana Fish, Wildlife and Parks, the fly shops guys here in Bozeman tell me they sell non-lead wire at a 3:1 clip over lead wire. The reason is clearly Yellowstone. Although the ban on lead is completely unenforceable when it comes to flies, it would be silly to jeopardize your Yellowstone fishing rights for the minuscule marginal increased cost of non-lead wire and slightly less weight to density. I can just imagine an overzealous park ranger slashing open my flies, taking a sample of wire for laboratory analysis on the suspicion that my flies sank too fast. That’s not beyond the realm of possibility given some of the other things the NPS is doing to its fisheries.
    Mike Cline, Bozeman, MT

    1. Thanks for the input Mike. Yes, the case agaist lead has been made, although I’ve always believed that it’s mostly based on the fear of waterfowl scooping up and eating lead pellets. It’s not that lead dissolves into solution, since the inert compound lead oxide swiftly coats it. Political people are rarely astute enough to see the distinction.

      There is small fly fishing lead shot available with polymer coating. It’s supposed to address the waterfowl risk as well (and I can only assume the polymet won’t break down in digestive systems). So I’ve been figuring that as long as I coat the lead I wind with head cement, it should be safe enough. I think if I lose a fly and an animal eats it, coated lead would be the least of its worries.

      But the debates about real risk aside, you’re right that zealous lawmen may be the most tangible concern we have. Maybe you’re right that it’s safest to just use lead-free wire…although it will make the fly 30% bulkier for the same sink rate. I haven’t frequented lead-free waters a lot, but when they all go that direction I’d like to know that I don’t have to toss out all my flies.

      So if we’re comparing fine tungsten wire to lead-free “lead look-alike” wire, I believe the tungsten will be 50% heavier so will sink faster, for the same bulk. Or it will weigh the same as the lead-free at only 66% of the bulk applied to the hook.

  2. “By length, the lead’s weight is about 3x the tungsten’s weight….. And remember that the lead wire’s diameter is 3x that of the tungsten’s. This means that the two materials, by volume (i.e., by “build-up” on a hook shank) will weigh ABOUT THE SAME. ”

    Not so. Wire is a cylinder. So the relative volumes of the two wires is NOT the ratio of the wires diameter 3:1 but of the respective volumes which is actually 9:1.

    To calculate the volume of two cylinders of identical length but differing diameters, you multiply the cross sectional area of the wire (which is a circle) x the length. Since the lengths of the two wires are identical, the identical lengths cancel out; and the weights
    of the wires are proportional to their respective cross sectional areas.

    Cross sectional area varies with the SQUARE of the radius. Since the radius of the lead wire is 3X the radius of the tungsten wire, the volume of the lead wire is 9X the volume of the tungsten wire and NOT 3X the volume of the tungsten wire.

    This assumes both wires are solid and discounts the air gaps between the wires so it is an idealized calculation that assumes volumes of material will result from the wrapping of the wire.

    1. The question is not specific gravity, though, nor is it assumption of a consistent cylindrical shape, and it’s most definitely not the cross sectional area of a single strand. It’s packing density when wound on a hook shank…as such it is affected by nesting, stiffness, quality control of the diameter, and other aspects. You come back around to the truth when you acknowledge you’re ignoring air gaps. So the calculation was simplified but not idealized, really. I did say “by build-up” and I did measure the mass. If you wind both carefully and measure carefully, as I did, you’ll come back around to my practical conclusions.

  3. You can easily Google whether tungsten or lead is a heavier material. Tungsten is 1.74 times heavier than the same amount of weight.

    1. The question is more than just specific gravity, else there’d have been no reason to look into it further. But I do appreciate your interest in the tungsten wire. Everyone draws the conclusions they find ring true in practice.

  4. Its important to protect the environment. Lead should never be used. Period. Birds, fish and all creatures are harmed when they come in contact with human made, concentrated balls of lead.

    1. Of course it’s important to protect the wilds Linette; everyone already understands that. However there are actually many many many many many ways to do it. Lead can be used as safely as it can be in the battery posts of that car you drive, and in the battery posts of the truck that brings you whatever fishing items or TU magazines you order…and the dead batteries that then get rained on in storage and eventual transit to wherever they’re recycled.

      Again, while the abrasion of explosively distributed lead shotgun pellets can temporarily do so, lead fishing weight actually does not expose lead to any of the critters you mention. It exposes nothing but a wholly inert compound that taints nothing because it is already inert–it’s non-reactive, to water, to O2 or Nitrogen of air, to rock particles and to vegetative matter. So why do they outlaw it in (some but not all) streams? It’s a rule that some adopt and others don’t, based on individual attitude–individual willingness to decide quickly–it’s a rule that is grounded in concern more than it is in real risk–and it’s a precaution that’s adopted because it’s easily enforceable as a one-sentence ban across all different sports and activities.

      So it is what it is; yes we ought to follow it to be safe. But where legal, use of lead weight wire on a fly, fully coated very well with a polymer or other reliable permanent coating like head cement or fingernail polish (just like split shot that’s coated in polymer and thus made legal by virtue of that coating), poses no known notable risk, any more than does dipping wading boots made of synthetic materials…or bare aluminum canoe paddle shafts…or royalex or kevlar boat sides…or epoxy-covered fly rod guide windings…into the water.

      By all means we should all hang onto our already-well-honed love of the wild. And I do…and I have for far longer than you can possibly know. It’s still admirable to be able to ascertain the difference between risk and rule…else where rules are not yet implemented we’ll lack the ability to know what still not to do.

      And anyway my article was mostly to compare the mechanical properties of the two products.

      Thank you for reading. Stay safe.

      – Mike

  5. It seems that ‘fly tying wire’, whether lead or non-toxic are not fully made of lead or non-toxic material (tungsten ?) – at least they do not measure as such. 12″ of Orivis’s .025 Non Toxic Fly Wire weighs .00254 lbs (11.12 grains), within tolerances for metal calculators on the web. If it was tungsten, it ought to weigh .0041 lbs (28.7 grains).

    I am awaiting delivery of several spools of other diameters of non toxic wire and assume that these will also show weight similarities to lead wire and that they are some kind of alloy to allow bending, etc., as tungsten itself is quite stiff.

  6. I appreciate the article, even though it’s 5 years on. The first comment is dated 2015. I wish it would become standard to include the publish date on all internet articles!

    Relative weight is the critical issue. Tungsten has an atomic weight of 184 while lead checks in at 207. So tungsten is about 10% lighter than lead. If you build up a layer around your hook shank with the same diameter, tungsten would be 10% lighter. And it would take a lot of wraps. For small nymphs where you care about body shape it seems that tungsten would be awesome. I think I’m going to try a beadless perdigon with tungsten underwrap. Lead free wire just isn’t dense enough.

    1. Thanks BlueWingOlive, for your thoughts. Yes, if wraps of pure tungsten wire had about the same volume of wrap-to-wrap air gaps as pure lead wraps, it should be a little lighter than the pure lead wire. My mass measurements showed that the air gap difference in the products I compared brought them around to approximate parity. As I said in a later comment, what matters is “packing density when wound on a hook shank…as such it is affected by nesting, stiffness, quality control of the diameter, and other aspects.”

      I chose to measure the mass of the wire products at my disposal rather than to base conclusions on specific gravity, mostly because I was not comparing tungsten with lead but instead a tungsten wire product with a lead wire product. I had no way of knowing what other materials were part of those products for workability or manufacturability or other reasons. So I compared products without pretending to precisely compare elements.

      The tungsten wire I tried was stiff and springy and not so easy to work with, I found, making smooth shape build-up at least a minor challenge. It has its place of course, but when it eventually unwinds it can be come a needle-thin, very sharp hazard to organisms that may contact or ingest it. Nothing is perfect, thus fine lead oxide wire wrapped and then completely encapsulated in a durable synthetic coating (like what I use), since such coatings have already been approved as safe in the form of reusable split shot, is even more safe than split shot when we make a fly that way and never bend it again.

      I have both types of wire, but I confess it has been years since I’ve found a need to use the tungsten. But that could be largely due to the kinds of flies I tend to tie (and the size…I rarely try to tie 18 or smaller). So go for it and I hope it works well for you–it is by any account a useful material.

      The article was submitted around January 2015, by the way. Thanks again. (Another article of quasi-similar intent that I submitted some time back was one that tested the strength and utility of UV-curable resin as an “instant” angling field adhesive; now and then I wonder about something and just put it to the test, and share what I learned.)

      – Mike

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