Activities The Great Outdoors Best Line Crimping Techniques Share PINTEREST Email Print Florida Fish and Wildlife/Flickr/CC BY-ND 2.0 The Great Outdoors Fishing Saltwater Fishing Freshwater Fishing Gear Fish Species Hiking Climbing Skiing Snowboarding Surfing Paddling Sailing Scuba Diving & Snorkeling Learn More By Tom Gatch Tom Gatch has over 20 years of experience as a writer focusing on saltwater fishing in Southern California and Baja. He authored the book "Hooked on Baja." our editorial process Tom Gatch Updated May 06, 2018 Most experienced saltwater anglers who pursue large gamefish like marlin, tuna and wahoo will agree that one of the most frustrating things that can happen is to have the connection between your line and leader fail during an intense battle with a trophy-sized adversary. This is a particularly common occurrence while using a wire leader unless that link has been reinforced with a metal crimp, sometimes referred to as a swag. Not using one could cost you the catch of a lifetime. Although making these types of connections may appear simple at first, learning how to consistently use a crimping tool to properly create a fail-safe bond between the line on your reel to your leader takes practice. It starts out with selecting the right type of crimp sleeve for the type of fishing that you plan to do. Crimping sleeves are generally made from aluminum, brass, copper or an alloy conglomerate. Aluminum sleeves are best used only for monofilament to monofilament connections because they will also instigate a corrosive reaction when joined with steel cable that can quickly compromise and weaken the connection as it oxidizes. The three types of crimp sleeves that are most commonly used by saltwater anglers are the double barrel sleeve, the oval sleeve, and the round sleeve. Types of Crimp Sleeves Double Barrel – These are the strongest and most reliable sleeves, but they cost a bit more than oval or round crimp sleeves. Double barrel sleeves are the go-to choice for commercial longliners and big game anglers aboard long-range sportfishing boats who are in search of huge tuna and marlin weighing several hundred pounds. Oval – This is probably the most popular sleeve with both inshore and offshore anglers because of its versatility in a number of configurations; when attaching a wire leader to your main line, or when connecting a wire leader to the hook at the terminal end of your rig. When compressed using the correct crimping tool, it makes a strong and reliable bond that can handle a wide variety of challenging situations. Round – Best suited for light tackle applications, the round sleeve is not particularly reliable when going after bigger fish. The soft brass that they are usually made from is too soft when subjected to the abuse that can be dished out by a serious gamester. It has been said by some that round sleeves are made for people who either do not want or know how to tie a good fishing knot. There are basically two types of crimping tools; point to cup and cup to cup. A point to cup crimper is relatively inexpensive and can be found at most well equipped sporting goods and tackle outlets. Similar in appearance to a sturdy pair of pliers or dikes, and have pointed interlocking teeth. They are designed to be used with round crimp sleeves, which are flattened against the line and leader without fully forming around them. On the other hand, the jaws of a cup-to-cup crimper have matching pairs of semicircular cups cut into them with 3 or 4 different sizes to accommodate a variety of sleeves. They are designed for use with either oval or double-barreled sleeves. Of these, there are three distinct levels of cup-to-cup crimping tools within the family. Types of Cup-to-Cup Crimping Tools A standard cup to cup crimper is generally all that will be needed by most recreational anglers. They are reasonably priced and can usually handle line diameters of up to 2 mm on monofilament line in the 400-pound class or 600-pound test wire. Heavy duty crimpers are available at a higher cost, but they are built tougher and last longer under heavy usage. They are the first choice of charter boat captains who consistently rely upon heavy duty sleeves to keep their client connected to a trophy-sized gamefish during a tough battle. Bench press tools are the most expensive cup to cup crimpers and are designed for use by commercial longline fishing operations, large tackle shops, and hardcore heavy tackle aficionados. These bench mounted tools are equipped with extended handles for added leverage and are not easily moved. They are best suited for industrial use. To make a simple loop with a crimp connection using monofilament line, select a suitable sleeve for the diameter of the line you plan to use. Pass the line through the sleeve and make a small loop then slide the tag end back through the sleeve in the opposite direction so that it extends an inch or two beyond the sleeve. Position the sleeve between the jaws of the crimper so that the concave faces of the cups push against the curved edges of the sleeve. Be careful not to go beyond to edge of the sleeve with your crimp or you risk damaging the line. At this point, take a small butane torch or a cigarette lighter and melt the tag end of monofilament until it balls up and the molten line can be pressed down over the end of the sleeve. Allowing that short tag end to remain on your rig may not seem like a big deal, but it will snag every bit of seagrass or kelp that it comes in contact with during your retrieve, so it is best to remove it. Hooks, swivels and other terminal accessories that are attached by using a crimped loop are infinitely stronger than if they were simply tied on; even when using the best fishing knots in the book. When joining mono to mono or mono to wire using the same method, a double barrel sleeve is highly recommended because it will link the two lines more snugly and provide maximum strength when the joint is properly crimped. The one error that is often made by those just learning to crimp occurs when they place the sleeve in the jaws sideways so that the teeth of the jaw presses down the central groove between the two barrels. Always be sure to place your sleeve in the crimper vertically so that fits inside the groove of the cups and the pressure is applied to the curved sides of the sleeve. A proper crimp deforms the metal of the sleeve in such a way that it wraps around your line and leader without damaging either end, as would simply squashing the sleeve down and flattening it. This is why it is absolutely essential that a crimping tool specifically designed for this purpose be used in making crimp connections. However convenient it might seem to try and use a pair of conventional pliers to perform the task, it is ill-advised to actually do so because your connection will be doomed to failure the first time it is truly put to the test. You can certainly purchase a suitable crimper and select the individual sleeves and accessories that you need separately. However, many anglers have found that spending a little extra on an all-inclusive crimping kit, which contains just about everything needed for a variety of situations, is a worthwhile investment. Remember that practice makes perfect, and it will take time to learn how to consistently make loop and line to leader connections with a crimping tool that stand up to the pressure. Taking the time to refine those skills at home in your free time will definitely pay off once you get out on the water. Professional sportfishing captains and their crews are expert in tying a variety of exceptionally strong knots to join the line to the leader that can withstand a heated battle with a large gamefish. These include the Double Uni, the Albright, the Bristol, the Seaguar and the Yucatan. But in the end, they would all have to admit that none of these knots can achieve the unfailing performance that can be delivered by a well-matched and properly executed crimp connection.