How to Splice Conveyor Belt

2. Splice Rubber Conveyor Belt

2.1 Rubber Conveyor Belt Types and Structural Differences

When I walk up to a belt that needs joining, my first step isn’t to grab the tools—it’s to figure out exactly what type of belt I’m dealing with. You can’t choose the right way to splice conveyor belts unless you know the belt’s internal structure. It’s like trying to fix an engine without knowing if it runs on diesel or gasoline.

EP fabric belts are the most common in heavy industry. The polyester warp gives them strength, while the nylon weft offers flexibility. This balance makes them excellent for applications where both load capacity and resistance to stretching matter. In practice, they handle hot vulcanizing very well, and if you follow the correct conveyor belt splicing procedure, the joint can reach 90–100% of the belt’s original strength. They can also be cold spliced in the field when speed and convenience are more important than ultimate tensile strength.

Then there are NN belts—nylon in both warp and weft. These belts absorb shock better than EP, which is why I see them in impact-heavy applications like mining or quarry work. The trade-off is that they stretch more under load, so splice alignment and tension calibration become critical. If you get lazy here, your splice will creep, and tracking will be a constant headache.

Steel cord belts, however, are in a league of their own. These belts have embedded steel cables running lengthwise, giving them extreme tensile strength. Splicing them isn’t just about bonding surfaces—it’s about aligning each cord individually, ensuring uniform load distribution, and using the exact temperature, pressure, and curing time during hot vulcanizing. I’ve seen more failures here than anywhere else, usually because someone tried to cut corners. Steel cord splicing is slow, meticulous work, but if you do it right, the splice is as strong as the belt itself.

Understanding these differences isn’t academic—it’s essential. Choosing the wrong method from the many conveyor belt splice types will shorten belt life, increase downtime, and cost far more in the long run. I’ve learned to respect each belt for what it is and to apply the method that matches its design and working conditions.

Next, I’ll walk you through each splicing method for these belts—hot vulcanizing, cold bonding, and mechanical fastening—so you can match the process to the belt type and keep your system running at its best.

2.2 Overview of Available Splicing Methods for Rubber Belts

Whenever someone asks me the “best” way to splice conveyor belts, I always give the same answer: It depends. I know, it’s not the magic bullet they were hoping for—but in this line of work, there is no single best. The right method depends on your belt’s structure, the load it carries, the speed it runs, and how much downtime you can afford before someone starts yelling about lost production.

For rubber belts, there are three main approaches: hot vulcanizing, cold bonding, and mechanical fastening. Each has its place, and each has its own set of pros, cons, and “if you do this wrong, you’ll regret it” moments.

Hot vulcanizing is my personal favorite when conditions allow. It’s the gold standard for achieving near-original belt strength—up to 100% if you follow the conveyor belt splicing procedure to the letter. The process uses heat, pressure, and uncured rubber to chemically bond the belt ends together. It’s not fast, it’s not portable, and it requires the right equipment, but when done properly, the splice is as smooth and durable as the rest of the belt. I’ve seen hot vulcanized joints outlast the belts themselves.

Cold bonding is the field-friendly cousin. Instead of heat, it uses a chemical adhesive to fuse the ends. It’s faster, doesn’t require heavy presses, and is perfect for emergency repairs in the middle of nowhere. The trade-off? You’ll get about 60–70% of the belt’s original strength, so it’s not ideal for high-tension, heavy-load applications. Think of it like a spare tire—it’ll get you moving, but you wouldn’t race on it.

Then there’s mechanical fastening, the speed demon of the group. With metal fasteners or clips, you can connect a belt in minutes. It’s perfect for temporary solutions, frequent belt changes, or systems where downtime costs a fortune. But, it’s also the noisiest and least smooth option—material can catch on the fasteners, and they can wear rollers faster. I use them when speed matters more than aesthetics or long-term durability.

Here’s the bottom line: each of these conveyor belt splice types has its place. The trick is knowing which tool to pull out of the box for which situation. That’s where experience comes in—because the difference between a good splice and a great splice often comes down to the judgment of the person holding the knife, adhesive, or vulcanizer controls.

Next, I’ll walk you through hot vulcanizing in detail, because while it’s the most demanding method, it’s also the one that can make your splice truly bulletproof.

2.3 Hot Vulcanization for EP / NN Belts

If there’s one method that makes me feel like a conveyor belt surgeon, it’s hot vulcanizing. When I want a splice conveyor belt job that’s rock-solid and nearly invisible in operation, this is my go-to. For EP (polyester/nylon) and NN (nylon/nylon) belts, it’s the closest thing to restoring the belt to its factory strength—up to 90–100% of the original tensile rating.

Here’s how I do it in the field, step by step:

1. 1. Cut and Square the Belt Ends
      I start by marking and cutting both ends perfectly square. If the cut’s off, everything else will be off. A crooked splice is like driving with misaligned wheels—you’ll feel it right away.
   2. Skive the Layers in Steps
      I skive the fabric plies into a step pattern. This increases bonding surface and ensures even load transfer across the splice. Skip this, and you’re basically asking the joint to fail early.
   3. Surface Preparation
      This is the messy but critical part: grinding to remove oxidized rubber, cleaning to get rid of dust, and making sure the surfaces are completely dry. Any contamination here will show up later as a weak spot.
   4. Apply Bonding Layers and Cover Rubber
      I brush on bonding cement in thin, even coats and place uncured cover rubber between each ply layer. Think of it like making a layered cake—except this one has to handle tons of tension.
   5. Assemble in the Vulcanizing Press
      Once stacked, I clamp the splice in the press. Heat and pressure are set according to belt specifications. Too hot and you’ll scorch the rubber; too cold and you’ll never get full adhesion.
   6. Curing Under Controlled Conditions
      I keep the splice under pressure for the exact time needed—no more, no less. It’s tempting to rush, but good vulcanizing is all about patience.
   7. Cool Down Under Pressure
      I always let the splice cool while still in the press. Releasing early can cause warping or delamination.
   8. Trim and Inspect
      Once cooled, I trim excess rubber, check alignment, and run a tension test. A good splice should be seamless in appearance and performance.

Hot vulcanizing isn’t the quickest method, but it’s the one I trust for long-term durability. When done right, you’ll forget where the splice even is—until someone asks why your belt is still running perfectly after years of service.

Next up, I’ll cover cold bonding—faster, more flexible, but with trade-offs you need to know.

2.4 Cold Vulcanization for EP / NN Belts

Cold vulcanizing is like the quick-response unit of the splice conveyor belt world. It’s the method I turn to when the clock is ticking, the line is down, and a hot press just isn’t practical. Instead of heat, we use chemical bonding agents—making it perfect for field repairs, remote sites, or emergency situations. For EP and NN belts, it’s fast and effective, though not quite as strong as hot vulcanizing (think 60–70% of original strength).

Here’s my field-proven process:

1. 1. Prepare and Square the Ends
      Just because it’s “cold” doesn’t mean it’s sloppy. I start by cutting both ends square. A crooked cut will haunt you later when you’re trying to align the splice.
   2. Grind the Surface
      Using a grinder, I remove the top layer of rubber to expose clean fabric plies. This increases the adhesive’s grip. If you skip this step, you’re basically gluing over dust—and it will fail.
   3. Clean Thoroughly
      I wipe both ends with a solvent to remove dust, oil, or moisture. Adhesive hates dirt. In high-humidity environments, I’ll even use a heat gun to ensure everything is bone-dry before moving on.
   4. Mix the Adhesive (if two-part)
      Some adhesives require mixing before application. I measure precisely—too much hardener and you get a brittle joint; too little and it never cures properly.
   5. Apply the Adhesive
      I brush adhesive onto both ends in thin, even coats. The first coat soaks into the fabric; the second creates the bonding layer. I wait until the surface is tacky—not wet—before joining.
   6. Join and Clamp
      Once ready, I bring the ends together carefully, making sure the plies align perfectly. Then I clamp them under steady pressure to ensure a uniform bond.
   7. Curing Time
      Cold vulcanizing isn’t “instant.” I let the joint cure for 24–48 hours depending on the adhesive. Trying to run the belt too soon is the fastest way to undo all your hard work.
   8. Inspect the Splice
      After curing, I inspect the bond visually and by hand, checking for gaps or soft spots. If it passes, it’s ready for service.

Cold vulcanizing is the rescue plan—not the long-term champion. But when you need the belt running again fast, this method can save the day (and your production schedule).

2.5 Mechanical Fasteners for Rubber Conveyor Belts — Materials, Styles, and Connection

When you need to splice conveyor belts quickly without a vulcanizing press, mechanical fasteners are the go-to solution. To get a strong, long-lasting connection, you need to choose the right material, the right fastener style, and install it correctly.

1. Fastener Materials

• • • Carbon Steel– Strong and economical for dry, non-corrosive conditions.If you use it in a humid environment or at a port, it is recommended that you do not use this type of steel as carbon steel is easily corroded.
    • Stainless Steel– Corrosion-resistant, ideal for wet or food-grade environments.The overall cost-effectiveness is the highest, and it can be used in a variety of conventional environments, but it is not recommended to be used in high temperature environments and acidic corrosive environments for a long time. Therefore, it is not recommended to use in acid and alkali resistant belts and conveying high-temperature coal ash.
    • Alloy Steel– High-strength option for extreme tension and heavy impact loading.It is not recommended to use it in strong acid and alkali environments, or in low temperature environments. When the temperature is below 40 degrees, its toughness will decrease, affecting its performance.

2. Common Fastener Styles for Rubber Belts

1.Clipper Fastener
With aggressive serrated teeth, this fastener grips deep into the belt cover and carcass, making it perfect for heavy-duty EP or NN belts in mining, cement, and bulk handling.

• • • • Best for:Long-term, high-strength splices where downtime is critical.

2.Hinged Fastener
Recognized by its wing-like flanges, it’s quick to install and works well with smaller pulley diameters, making it a favorite for medium-duty belts in quarries, agriculture, and on-site maintenance.

• • • • Best for:Temporary to semi-permanent splices that need flexibility and speed.

3.Flat Plate Fastener
A solid plate clamping design that spreads load evenly across the belt end, suitable for a variety of fabric-based rubber belts.

• • • • Best for:General-purpose splicing where space and pulley size aren’t restrictive.

3. Step-by-Step Connection Procedure

1.Prepare and Square the Belt Ends – Use a belt cutter or straight edge to achieve perfectly square ends. Misalignment will cause uneven tension and shorten splice life.

2.Mark Hole Positions – Align the fastener template with the belt centerline. Mark each hole for precision grip.

3.Punch the Holes – Use the correct punch size. Avoid tearing fabric plies; clean cuts maximize holding power.

• • • • Clipperand Hinged fasteners often need deeper penetration to seat teeth or wings.
      • Flat plates require evenly spaced bolt/rivet holes for uniform clamping.

4.Install the Fastener –

• • • • Clipper:Tap serrated section so teeth embed into the belt cover.
      • Hinged:Align wings flush with the belt surface.
      • Flat Plate:Position plates on both sides for full overlap.

5.Secure the Fastener – Tighten bolts or rivets gradually from the center outward. For hinged designs, leave slight movement for pulley passage.

6.Insert Connecting Pin (if required) – Ensure smooth movement. Nylon-coated pins reduce noise and wear.

7.Test Run at Low Speed – Observe for lifting edges, misalignment, or unusual noise. Stop to adjust if necessary.

8.Final Tightening & Inspection – Once aligned, fully tighten and verify all components are seated correctly.

9.Routine Maintenance – Inspect weekly for heavy loads or monthly for light duty. Replace worn parts before failure.

Pro Tip: Even the strongest Clipper fastener will fail early if installed poorly, while a Hinged or flat plate can last surprisingly long with proper technique. In mechanical splicing, precision matters more than the type of fastener.

2.6 Splicing Steel Cord Conveyor Belts — My Field-Tested Approach

If you’ve ever worked with steel cord conveyor belts, you know they don’t forgive mistakes. These belts carry massive loads over long distances, and every splice is under constant stress. I’ve seen perfectly good belts scrapped early because the splice wasn’t done right. So here’s how I approach it when I want the splice to last for years, not months.

1. Understanding the Challenge

Steel cords aren’t just reinforcement—they are the backbone of the belt. Each cord must line up exactly with its original position so the tension is evenly shared. One misaligned cord can throw off the load balance and start tearing the splice apart from the inside. That’s why I stick to hot vulcanizing for every steel cord job. It’s the only method that restores the belt’s original strength.

2. My Step-by-Step Process

1.Tag Every Cord
Before cutting, I mark and number every steel cord. This isn’t optional—mixing them up will create uneven pull across the belt.

2.Cut in a Stepped Pattern
I never cut cords straight across. A staggered, step-like cut spreads the stress and prevents a “hard break” at one point.

3.Rust Protection First
The moment those cords are exposed, I coat them with rust inhibitor. Even a little moisture can start corrosion that keeps eating away after the splice is done.

4.Fill Between the Cords
I use uncured rubber to restore the belt’s profile and cushion between cords. The filler has to bond completely—no voids allowed.

5.Cover Layers Matter
Top and bottom covers are laid so there’s a smooth, even thickness. Any trapped air is trouble waiting to happen, so I work methodically to press it out.

6.Precise Vulcanizer Setup
In the press, I double-check alignment and settings. I control temperature and pressure like a recipe—too hot, too cold, too quick, too slow, all can ruin the splice.

7.Full Cooling
I don’t rush cooling. Pulling the belt out warm is asking for internal separation. I let it cool naturally in the press.

8.Final Inspection and Record
Once done, I measure splice length, check cord alignment, and note every detail for the maintenance log. This record saves headaches later.

3. My Key Advice

• • • Keep the work area dry—moisture is the silent killer of steel cord splices.
    • Use trained hands only; this isn’t a job for first-timers.
    • Don’t cut corners on materials—cheap filler or covers are a false economy.

A well-made steel cord splice is invisible in operation—you’ll forget it’s there. A bad one will remind you every time it fails. Do it right the first time, and it’ll handle the pressure for years.

2.7 Choosing the Right Rubber Belt Splice — My Quick-Reference Guide

Over the years, I’ve lost count of how many times someone asked me, “Which splice should I use?” Truth is, there’s no one-size-fits-all answer. The right splice depends on your belt type, your operating environment, your budget, and how much downtime you can afford. Here’s my own go-to table, followed by my personal take on each option.

1. Quick Selection Table

2. My Notes and Advice

• • • Hot Vulcanizing for EP/NN Belts
      If you have the time, equipment, and trained technicians, this is hands down the best choice. It restores almost all the belt’s original strength and works well for high-load applications. Just remember, sloppy alignment here wastes all your effort.
    • Cold Vulcanizing for EP/NN Belts
      Perfect when you’re in the middle of nowhere and can’t set up a vulcanizing press. I’ve done cold splices that lasted surprisingly long—but only when the prep was meticulous. Humidity is your enemy here.
    • Mechanical Fasteners for Fabric Belts
      I use these when speed matters more than strength—like temporary bypass lines or belts you need to swap frequently. Keep in mind, they can catch material and wear pulleys faster. Choose stainless or alloy versions if corrosion is a concern.
    • Hot Vulcanizing for Steel Cord Belts
      Don’t even think about other methods. Steel cord splicing needs precision, and hot vulcanizing is the only way to match original tensile strength. Anything else is a ticking time bomb.

3. My Shortcut Rule

If the belt is critical to production, go hot vulcanizing. If it’s temporary or low load, cold vulcanizing or mechanical fasteners will do. And if you’re handling steel cord, you already know—you’ve got just one real choice.

When in doubt, I ask myself: “Do I want to fix this again in six months?” If the answer is no, I go for the method that will outlast the belt itself.