How to choose the best slotted tungsten beads.

MOST popular slotted tungsten beads you tie with suck and you probably don’t even know it. Let’s get deep and nerdy into the world of tungsten beads. The beads easily taken for granted to get our nymphs down into the strike zone. You’re choosing Tungsten because you want the heaviest beads, right? So stick around to learn what to look for. You’ll never look at beads the same way again.

Okay. In order to know which beads are “good” and “bad” we first need to talk about what beads need to do. We’re trying to balance choosing a bead that fits your flies’ proportions and is as heavy as possible. That’s why we’re choosing Tungsten over brass. It’s heavier.

So here is what I’ve done. I've purchased slotted tungsten beads from most of the big suppliers.

In a perfect world, they'd all be the same size so I can directly compare them, but they don't all offer the same size. So I'm using their bead closest to 3.5mm without going over.

And to directly compare them I'm going to create two scores so we can fairly compare the different sized beads. More on that later.

To figure all of this out we're going to look at 3 major things:
#1 I’ll take accurate mass measurements using a gram scale and from there measure their volume and attempt to calculate how pure the tungsten is. AKA, how dense are they?

#2 I'm going to measure how wide the hook gaps are and see how that impacts overall mass.

#3 And last, I'm going to look at quality control and consistency. Are all the beads in a pack the same size? Do they have any sharp edges that cut thread?

Equipped with actual data, we can figure out which beads are worth your money! If you’d like the TLDR; jump to the end where I have all the beads sorted from best to worst. For those that like to get into the weeds, let’s go deeper.

Tungsten Purity

The most common thing people talk about is Tungsten purity. I’ve seen countless forum discussions talking about and speculating who has the purest tungsten and thus the heaviest beads. Using a magnet they’ll argue that if they contain iron and sticks to a magnet they’ll conclude that it’s not pure Tungsten and will be lighter than a bead that doesn’t react to a magnet. That is sound reasoning and purity is interesting to talk about in forums, so find out if magnetism actually matters.

The Test Setup

I’ve carefully weighed each bead using a gram scale. To account for margin of error and small bead inconsistencies, I’m weighing 10 beads at a time and using an average. Since they are all slightly different sizes, knowing their absolute mass isn’t enough to straight up compare them. So let’s build on that and figure out how dense they are. For that, I’ll need to know their volume.

Since they’re hollow, I can’t just measure their dimensions with a micrometer. I need to use water displacement to figure this out. So, I precisely filled a 5ml graduated cylinder with 2mls of distilled water. I added beads until the water was raised by 1/2ml. Taking that volume of water divided by the number of beads submerged, I can calculate the volume of each bead and determine the density.

The higher the density, generally speaking, the more pure the tungsten is. I worded that vaguely because I can't really say what metals are used. Most common metals like iron, nickel, copper, and lead are much less dense so any amount of non-tungsten metal will affect the overall density. There are metals like Iridium and Osmium that have greater density, but they're rare and unlikely to be present in any significant quantity. All of that to say, you want to have the greatest density possible, no matter what metals may actually be present.

So on my first round of measurement, I learned that the surface tension on the beads was holding bubbles inside the gaps. This is bad because the bubbles displace extra water and will skew the volume upward, making the beads appear more dense than they actually are.

To mitigate this, I tried swirling the graduated cylinder and that would release SOME bubbles. But I could still see more holding on. Next, I start lightly tapping the cylinder on my bench and hundreds of micro-bubbles would get released. This seemed to work, but with every single tap, more and more bubbles would escape. There was never a point where the bubbles would stop getting released. Unsure of what to do at this point, I figured the amount of air trapped after a number of taps was small because I couldn’t see bubbles on the beads anymore. So I ran the numbers on each brand after 10 taps.

Here’s what I found. Hanak and Aventik beads are the most dense.

Case closed right?

WELL, the density of pure tungsten is 19.2g/ml, so right off the bat, we know I wasn’t able to get all the air out. The Hanak and Aventik beads were both measured over 20g/ml.

Consulting with fellow fly fisherman and professional research lab manager, Rosin. He suggested I use a sonicator. It’s a piece of equipment that uses ultra-sonic sound to break up and release the trapped gasses. An actual Sonicator is super expensive, way outside the scope of this project. There are cheaper Ultrasonic baths, for cleaning things like jewelry. That might have got me close, but I don’t think any of this really matters. Let me explain.

Circling back to our goal. We want the heaviest bead for a given size. That’s why the industry has shifted away from brass beads and lead wire wraps to Tungsten beads. May I turn your attention to the next data point, the width of the hook gap.

Hook Gaps

Beads with wider gaps have less metal inside than beads that have narrow gaps. Less metal means they’re lighter. This may seem obvious, but NOBODY talks about this. I’ve had many conversations talking about using magnets to compare tungsten purity and almost no one mentions hook gaps.

Magnetism

Just a quick side note about magnetism. Only two packs of beads had no magnetic effect and I found no measurable correlation to how heavy they are. Ironically, one of the two bags of Wholesale Fly Company’s beads was magnetic. This is skipping ahead to bead consistency, but it was odd that one bag reacted and the other did not. I don’t know how much Iron, Nickel or Cobalt an alloy needs to react to a magnet, but it must be small. Magnetism played no significant effect on how heavy they are.

So back to hook gaps. Using a digital micrometer, I made accurate measurements of the gaps and the results speak for themselves.

I created a score relating the gap to its diameter so we can easily compare the different bead sizes. A higher score means the slots are narrower. Sorting the results by this score, you can see that the beads with the higher gap score are the heaviest. More metal makes them heavier, go figure.

Another interesting way to look at this is to compare the diameter of the bead with its mass. This score is a proxy for volume, something I was trying to calculate earlier to measure their density. Adding these mass scores to the mix, you can see they also directly correlate to the hook gap. A lower score is better here.

Hook gaps are clearly the biggest factor in affecting how heavy your beads are. Simply put, the beads with the narrowest gaps are the heaviest. Full stop.

Fly Tying

Narrow gaps don’t just make your fly sink faster. They also make the beads much faster to lock in using fewer thread wraps. If the beads are sloppy, it can take 15-20 wraps to lock them in. You are wasting a bit of thread, but most importantly you’re wasting your time. With tight gaps, you can lock a bead in with about 5 wraps. That’s it. This is great for patterns where thread build up behind the bead can be a problem. Less build up gives you more room to tie in bulky things like soft hackles or a dubbed collar.

So you get a faster and higher quality tie.

Consistency

There are any number of things that can go wrong when you pick up a bag of beads and I don’t think any manufacturer is immune from this. Sometimes imperfections get through. Much of what you hear about is anecdotal and even with my research, I have just a single bag of some of these brands so it’s a pretty small sample size.

Early in my tying days, I picked up several bags of Wholesale Fly Company beads on several recommendations from tyers. They’re cheap, almost absurdly cheap. But I quickly found many of their beads have sharp burrs on them and I was cutting thread, a lot. So even though the price is right, they’re not worth it. They also have some of the widest gaps, so I’d probably keep shoping.

Fulling Mill was another big surprise for me. The actual size of the beads was super inconsistent. The package said they were 3.2mm, but I measured everything between 3.3-3.65mm. That’s pretty bad. Many of the brands varied slightly between their measured diameter and the package size, but they were consistent bead to bead. I don’t know if this bag was a fluke, but do keep an eye out for this with Fulling Mill beads. Anecdotely, I read a post where someone complained their Fulling Mill beads had thread cutting burrs like Wholesale Flyco does. So YMMV.

Conclusion

When you’re shopping, hook gap is something that’s easy to see when you’re comparing brands on the shelf. But your local fly shop might only carry a brand or two. To see how everyone stacks up, you can read through the chart at the end. That’s a resource I plan to update with time adding different sizes, brands and colors. It will be a living document, so be sure to bookmark it.

You may notice Driftstone beads are at the top of that list. When my friend and YouTuber Troutflies first shed light on hook gaps for me, I went on the hunt to find the best beads. At the time, I found Firehole and Aventik were decent, but it frustrated me that 90% of the beads out there have wide gaps and worse yet, no one was talking about it. I wanted to help the tying community out, so I sought out a manufacturer that would make beads with the narrowest gaps.

So, I’ve found what I think are the best beads you can buy, anywhere. I have them in popular colors (like copper, gold, silver black nickel and matte black) at very competitive prices because there’s no middle man. If you’re a fly tyer who ties with beads, check out the shop and pick up some up. You won’t be able to tie on sloppy beads again.

Oh and one more thing. If you know a fly tyer, it would mean a ton to me if you share this article with them. Bringing these beads to market has been very time consuming and took some financial investment, so spreading the word helps a ton. Buying products in the shop is the best way to support me and the channel. As I said above, they’re probably the best beads on the market and they’re very affordable. So thank you and good luck on the water. Goodspeed everyone!

The Results

Brand	Color, Size	Diameter (mm)	Gap (mm)	Mass (g)	Gap Score (bigger is better)	Mass Score (lower is better)	Magnetic
Driftstone	Matte Black 3.5mm	3.6	.78	.32	4.6	11.3	Y
Driftstone	Copper 3.5mm	3.45	.78	.30	4.4	11.5	Y
Munn	Gold 3.5mm	3.45	.81	.30	4.3	11.5	Y
Firehole	Copper 3.5	3.56	1.1	.33	3.2	10.8	Y
Hanak	Gold 3.5mm	3.5	1.09	.32	3.2	10.9	Y
Tactical Fly Fisher	Matte Olive 3.3mm	3.55	1.11	.31	3.2	11.5	Y
Aventik	Gold 3.5mm	3.46	1.15	.31	3.0	11.2	Y
Fulling Mill	Gold 3.2mm	3.3-3.65	1.21	.28	2.9	12.4	N
Wholesale Fly Co	Black 3.5mm	3.5	1.26	.28	2.8	12.5	Y
Wholesale Fly Co	Gold 3.5mm	3.47	1.31	.28	2.6	12.4	N
Hareline	Gold 3.3mm	3.23	1.35	.22	2.4	14.7	Y