How to Make Plastic Fishing Lure Molds

Table of Contents

1. Introduction
2. Why Make Your Own Lure Molds?
3. Choosing Your Mold Material
4. Essential Safety and Equipment
5. Preparing the "Master" Lure
6. Step-by-Step: Making a Plaster of Paris Mold
7. Making Silicone Molds for Complex Baits
8. Troubleshooting Common Mold Issues
9. Preparing the Mold for the First Pour
10. The Role of BattlBox in Your Gear Setup
11. Conclusion
12. FAQ

Introduction

There is a specific kind of frustration that every angler knows: the bite is on, the fish are hitting one very specific color or shape of soft plastic, and you just lost your last one to a submerged stump. Or perhaps you have an idea for a tail design that doesn’t exist on any retail shelf. Learning how to make plastic fishing lure molds is the bridge between being a gear consumer and a gear creator. At BattlBox, we value the self-reliance that comes with mastering your own equipment, and you can subscribe to BattlBox when you're ready to keep good gear coming every month. This guide will walk you through the technical process of designing, casting, and sealing your own molds using materials ranging from affordable plaster to professional-grade silicone. By the end of this article, you will understand how to transform a concept or an existing bait into a repeatable production tool for your tackle box.

Quick Answer: To make a plastic fishing lure mold, you create a "master" lure, place it in a casting box, and pour a mold material like Plaster of Paris or RTV silicone over it. Once cured, the master is removed, leaving a cavity that can be filled with liquid plastisol to create custom soft plastic baits.

Why Make Your Own Lure Molds?

The primary reason most outdoorsmen start making their own molds is customization. Commercial manufacturers produce baits designed to appeal to the widest possible market, but local conditions often require something more specific. Whether it is a unique scent profile, a specific buoyancy for a finesse rig, or a color laminate that mimics a local baitfish, making your own molds puts the control in your hands. If you want to keep that same mindset in your tackle box, the Hunting & Fishing collection is a useful place to start.

There is also a significant cost-benefit over time. While the initial setup for safety gear and mold materials requires an investment, the cost per lure drops drastically once you are pouring your own. For more ideas on what anglers keep in the tackle box, see Must-Have Fishing Lures for Every Angler. You can also recycle old, torn-up plastics by melting them down and re-pouring them into your custom molds, ensuring that nothing in your kit goes to waste. Finally, there is the undeniable satisfaction of catching a trophy fish on a piece of gear you engineered from scratch.

Choosing Your Mold Material

Before you start pouring, you need to decide which material fits your budget and the complexity of the lure you want to create. Not all molds are created equal, and the material you choose dictates the longevity and detail of your finished baits. If you want a related DIY angle, How to Make Fishing Lures Out of Wood pairs well with this stage of the process.

Plaster of Paris (POP)

This is the most common entry point for DIY lure makers. It is incredibly inexpensive and available at almost any hardware store. It is excellent for "open pour" molds, where one side of the bait is flat. However, plaster is porous and fragile. It requires a sealing process to prevent the hot plastic from sticking or creating air bubbles.

RTV Silicone

Room Temperature Vulcanizing (RTV) silicone is the gold standard for high-detail and complex shapes. Because it is flexible, you can create "undercuts" and intricate fins that would be impossible to remove from a rigid plaster mold. It does not require sealing and is naturally heat-resistant. The downside is the higher cost of the silicone itself.

Aluminum and Resin

Aluminum molds are what professionals use. They are CNC-machined and last forever, but they are generally beyond the reach of a home DIYer unless you have a milling machine. Resin is a middle ground; it is more durable than plaster but more rigid than silicone.

Key Takeaway: Start with Plaster of Paris if you are on a budget or learning the basics, but move to RTV silicone if you want to produce professional-quality swimbaits with complex details.

Essential Safety and Equipment

Working with the materials required for lure making involves high heat and chemical fumes. You must treat this process with the same respect you would give to any workshop task involving power tools or fire.

Safety Gear:

• Respirator: Liquid plastisol (the material used to make the actual lures) and some resins emit toxic fumes when heated. A Parcil Safety ProGuard OV/P95 cartridge with organic vapor cartridges is mandatory.
• Heat-Resistant Gloves: You will be handling liquids at temperatures between 300°F and 400°F. Leather work gloves or high-temp silicone gloves are essential.
• Eye Protection: A "burp" in the plastic or a splash during the mold-making process can cause permanent injury, so the Medical & Safety collection is a smart place to look for PPE.
• Ventilation: Never work in a closed kitchen or basement. A garage with the door open or a dedicated outdoor shed is best.

If you spill it while hot, it will continue to burn until it is cooled, so keep a My Medic Sidekick Standard close by.

Required Tools:

• Dedicated Microwave: Never use the same microwave for food and lure making. Plastisol leaves behind residues that you do not want in your lunch.
• Pyrex Measuring Cups: Glass is preferred for heating plastic. Avoid plastic containers, as they can melt or leach chemicals.
• Casting Box Materials: Foam board, hot glue, and aluminum foil are perfect for creating the "container" for your mold.

For compact carry gear beyond the bench, the EDC collection lines up with the same hands-on mindset.

Note: Plastisol sticks to the skin like napalm. If you spill it while hot, it will continue to burn until it is cooled. Always wear long sleeves and pants, even in summer.

Preparing the "Master" Lure

The "master" is the original object you are using to create the cavity in your mold. You have three main options for a master:

1. An Existing Lure: You can use a retail bait that you like and want to replicate or modify.
2. A Wood Carving: For those with woodworking skills, carving a master out of poplar or basswood allows for a completely original design. A Camillus 7.5" Marlin Spike Folding Pocket Knife is a handy stand-in when you're shaping a wood master or cleaning up a part line.
3. Clay Models: Non-sulfur modeling clay is excellent for sculpting a master, especially for thick-bodied baits like craws or creature baits.

Orientation is critical. When placing your master in the casting box, decide where the "part line" will be. For a simple one-piece mold, you want the flattest side of the lure to be facing up. For a two-piece mold, you will submerge the master halfway into a bed of clay before pouring the first half of the mold.

Step-by-Step: Making a Plaster of Paris Mold

This process is the most accessible way to start. Follow these steps to ensure your plaster mold doesn't crack or fail during its first use.

Step 1: Build the Casting Box Cut pieces of foam board to create a small box roughly one inch wider and longer than your master lure. Secure the sides with hot glue. Line the bottom with aluminum foil or a piece of glass to ensure a smooth surface. If you are working in a dim garage, a Powertac E3R Nova - 820 Lumen Rechargeable Flashlight helps you see details clearly.

Step 2: Secure the Master Place a small dab of hot glue or double-sided tape on the side of the master you want to be "flat." Press it firmly into the bottom of the casting box. You must ensure the master is held down; otherwise, it will float to the top once you pour the plaster.

Step 3: Apply Release Agent Lightly coat the master and the inside of the box with a release agent. You can use specialized mold release spray, or a thin coat of vegetable oil or petroleum jelly. This prevents the plaster from sticking to your master.

Step 4: Mix and Pour the Plaster Mix your Plaster of Paris according to the package directions (usually two parts plaster to one part water). Stir slowly to avoid creating air bubbles. Pour the mixture into a corner of the box and let it flow around the master rather than pouring directly onto it. This helps prevent air pockets from being trapped in the details.

Step 5: De-gas and Cure Gently tap the sides of the box or vibrate the table to encourage air bubbles to rise to the surface. Let the mold sit undisturbed for at least 24 hours. Even if it feels dry to the touch in an hour, the internal structure needs time to stabilize.

Step 6: Remove the Master Carefully pull away the foam board walls. Turn the mold over and gently pry the master lure out of the plaster. If you used a release agent, it should pop out relatively easily.

Step 7: Drying and Sealing Plaster holds moisture, which will turn into steam and ruin your lure if you pour hot plastic into it immediately. Place the mold in an oven at 200°F for two hours to completely dry it out. Once cooled, coat the inside of the cavity with a high-heat epoxy or a 50/50 mix of water and white glue (Mod Podge). This seals the pores and gives your finished lures a glossy look.

Bottom line: A Plaster of Paris mold is a cheap, effective way to learn, provided you take the time to dry and seal it properly before the first pour.

Making Silicone Molds for Complex Baits

If you are trying to replicate a bait with thin ribs, long spindly legs, or deep textures, plaster will likely break when you try to remove the lure. This is where RTV silicone shines.

The process for a silicone mold is similar to the plaster method, but with a few key differences. First, you do not need to seal a silicone mold. It is naturally non-stick and heat-resistant. Second, you must be more precise with your mixing. Most RTV silicones come in two parts (a base and a catalyst) that must be measured by weight or volume exactly as the manufacturer specifies. If you're comparing lure styles and what actually gets bites, What Lures Catch What Fish is a solid companion read.

Myth: You can make a professional mold by mixing hardware store silicone caulk with dish soap. Fact: While this "hack" can work for very simple shapes, it often results in a mold that shrinks, warps, or fails to capture fine detail. For fishing lures, dedicated RTV mold-making silicone is worth the investment.

Troubleshooting Common Mold Issues

Even experienced lure makers run into problems. Most issues can be traced back to the mold-making stage rather than the pouring stage.

• Air Bubbles in the Mold: This is usually caused by pouring the mold material too fast or failing to vibrate the mold after pouring. If you see bubbles in the cavity after the mold cures, you can fill them with a tiny bit of epoxy, but it is often better to re-pour the mold.
• Sticky Lures: If your finished plastic lures are coming out of the mold feeling "tacky," your plaster mold might not be fully sealed, or your silicone might not have cured properly.
• Tearing on Removal: This happens when the mold has "undercuts." If a rigid plaster mold wraps around a part of the lure, it will trap the master. Ensure your master has a clear "exit path" or switch to a flexible silicone material.
• Flashing: This is when thin sheets of plastic seep out of the cavity. It usually indicates that your mold surface isn't perfectly flat. For two-piece molds, it means the two halves aren't clamping together tightly enough.

Preparing the Mold for the First Pour

Once your mold is finished, sealed, and dry, it’s time to prepare it for its first run of plastisol. Even a perfectly made mold needs a little help. If you want better bench light and backup illumination, the Flashlights collection is worth a look.

Worm Oil and Lubrication: Before your first pour, and every few pours thereafter, brush a very light coat of "worm oil" into the mold cavity. This acts as a lubricant, helping the hot plastic reach every corner of the mold and making it easier to pull the finished lure out without tearing it.

Pre-Heating the Mold: Cold molds can cause the plastic to "shock," which leads to surface wrinkles or incomplete pours. This is especially true for plaster and aluminum. Before you start your production run, place your molds in the sun or near a warm (not hot) heat source. If you are using plaster, ensure it is completely dry; any residual moisture will turn to steam and cause the plastic to "burp" dangerously.

The Role of BattlBox in Your Gear Setup

While making your own lures is a fantastic way to customize your approach, having a solid foundation of professional gear is equally important. At BattlBox, we specialize in providing high-quality, expert-curated gear that fills the gaps in your outdoor kit. Whether you are looking for the best terminal tackle to rig your custom lures or the cutting tools needed to carve your master designs, our monthly missions deliver the gear you actually need in the field, and you can choose your BattlBox subscription to keep the right tools coming. We have shipped over 1.7 million boxes to outdoorsmen who value preparation and quality. Integrating custom-made lures with the professional-grade gear we provide ensures you are ready for any scenario on the water.

Conclusion

Learning how to make plastic fishing lure molds is a progression in your journey as an outdoorsman. It moves you from a passive participant to an active creator, allowing you to tailor your gear to the specific needs of your local waters. Whether you choose the cost-effective route of Plaster of Paris or the high-detail capability of RTV silicone, the key is patience in the curing and sealing phases.

• Safety first: Always use a respirator and work in a ventilated area.
• Master your master: Spend time making your original lure perfect, as every flaw will be replicated.
• Seal the deal: If using plaster, ensure it is bone-dry and sealed with a high-heat coating.
• Practice makes perfect: Your first mold might not be perfect, but the ability to recycle your plastic means the only thing you lose is a little time.

Building your own lures is part of the broader lifestyle of self-reliance. To continue building your outdoor skills and your gear collection, consider exploring our curated selections or joining the community to get the best survival and outdoor gear delivered to your door with get BattlBox delivered monthly.

FAQ

What is the cheapest material to make a lure mold?

Plaster of Paris is the most budget-friendly material for making lure molds. It is widely available at hardware stores and is easy to work with for beginners, though it requires careful drying and sealing with epoxy or Mod Podge to function correctly with hot plastisol.

Do I need to seal a silicone lure mold?

No, RTV silicone molds do not require sealing because the material is naturally non-stick and highly heat-resistant. This is one of the primary advantages of silicone over plaster, as it allows for a faster transition from making the mold to pouring your first lures.

Can I melt down old fishing lures to use in my new mold?

Yes, you can recycle old, torn, or unused soft plastic lures by melting them down in a dedicated microwave. If you want the water-side version of this DIY process, How to Use Lure Fishing is a useful follow-up. Ensure the old plastics are clean and dry, as dirt or moisture can cause the plastic to bubble or "burp" dangerously when heated.

Why are my plaster molds cracking?

Plaster molds usually crack due to residual moisture or extreme temperature shocks. If the plaster isn't fully cured and dried in an oven before you pour 350°F plastic into it, the trapped water turns to steam and expands, causing the mold to fail or even explode.