Fly Line Welded Loop Strength Test: Can You Trust Manufacturer Loops? | Tom Rowland Podcast Ep. 880

In Episode 880 of the Tom Rowland Podcast, Tom tests the strength and reliability of welded loops on fly lines, specifically examining whether anglers should trust the manufacturer's loop that comes pre-installed on modern fly lines like Cortland. Many experienced fly fishermen have never tested these welded loops and simply don't know how strong they are. In this How 2 Tuesday episode, Tom puts a brand new Cortland fly line to the test, measuring exactly how much force the welded loop can withstand and revealing whether it's stronger than the fly line itself. The results might surprise you and could change how you rig your fly fishing setup for tarpon, permit, and other saltwater species.

Why Fly Fishermen Don't Trust Welded Loops

For years, experienced fly anglers have approached the welded loops on modern fly lines with skepticism. These factory-installed loops have become standard on most quality fly lines, appearing on both the backing side and the leader side of lines from manufacturers like Cortland. Despite their convenience for creating loop-to-loop connections with leaders, many seasoned fishermen have simply never tested them to failure. They don't know if these welded loops will hold up to a charging tarpon or whether the connection point represents a weak link in their system. Tom addresses this exact concern by putting a brand new Cortland fly line through a systematic strength test. The welded loop wasn't fatigued or stressed before testing—it came straight out of the package. What Tom discovers about where the failure point actually occurs could change how you think about rigging your fly line. The complete welded loop strength test begins at 02:28.

The Loop-to-Loop Connection Method

Tom explains that there are many ways to attach your fly line to your leader, but the loop-to-loop connection has become one of the most popular methods among serious fly fishermen. This approach involves using the welded loop manufactured into the fly line and connecting it to a double overhand loop or surgeon's loop tied in the butt section of your leader. The beauty of this system is that it creates a relatively smooth connection that flows through your rod guides without hanging up, while also allowing you to quickly change leaders when needed. The question that haunts many anglers is whether they should trust that manufactured welded loop or cut it off and create their own connection. Tom's testing methodology is straightforward—he uses a brand new Cortland fly line with welded loops on both ends and applies increasing force until something breaks. The setup mimics real fishing conditions where your tippet might be anywhere from 12 to 40-pound test. Tom explains the loop-to-loop rigging method at 01:49.

The Test Results: 46.97 Pounds

When Tom finally pushes the Cortland fly line to its breaking point, the numbers tell a clear story. The welded loop held firm all the way to 46.97 pounds of force—and here's the critical detail—the actual welded loop didn't fail. Instead, the fly line itself broke. This reveals something important about the engineering of modern fly lines: the welded loop is actually stronger than the core material of the line. For practical fishing applications, this means if you're using 12, 16, 20, 30, or even 40-pound class tippet, the welded loop will never be your weak point. The tippet will break long before the welded loop fails. Tom notes one interesting limitation in fly line manufacturing—nowhere on the fly line packaging does it state what the breaking strength of the core actually is, which could vary between different models and manufacturers. He plans to test additional fly lines to see if this pattern holds across brands. The moment the fly line breaks and Tom analyzes the failure point starts at 03:15.

What This Means for Your Tarpon Setup

The practical implications of this test extend directly to how you should rig your fly fishing setup, especially for powerful saltwater species like tarpon. Tom specifically mentions tarpon fishing scenarios where anglers might be using heavier tippets—even up to 100-pound test in some extreme situations. For the vast majority of fly fishermen using standard tarpon class tippets, the welded loop on a quality fly line like Cortland will never be a concern. Your 16-pound tippet for smaller tarpon or your 20-pound class setup for larger fish will always break before the welded loop fails. This testing should give confidence to anglers who have been cutting off their welded loops and creating custom connections. Unless you're in that rare 100-pound test category, you can trust the manufacturer's loop. The smooth profile of the welded loop also means better flow through your guides during the cast, which can improve your presentation and distance. Tom emphasizes that he'll continue testing different fly line brands to build a more complete picture. Tom discusses the tippet strength implications at 03:35.

Final Thoughts from Tom

I've talked to countless fly fishermen over the years who have cut off their welded loops without ever knowing whether they needed to. There's this prevailing skepticism in the fly fishing community about trusting manufacturer connections, and I get it—when you're fighting a fish of a lifetime, you want to know every part of your system is solid. But data matters, and this test gives us real numbers to work with.

What surprised me most wasn't just that the welded loop held to almost 47 pounds, but that it outlasted the fly line itself. That tells me the engineering on these loops is sound. For the typical saltwater fly fisherman chasing tarpon, permit, or bonefish with standard class tippets, this should put the concern to rest. Your tippet is going to break before that welded loop ever fails.

I'm planning to test more fly lines from different manufacturers because I want to see if this pattern holds across the board. But based on this Cortland test, you can fish with confidence using those factory welded loops. This is practical information that can save you time on the water and give you peace of mind when a big fish takes off on you. Listen to the whole thing and see the test results for yourself.