How to Make Soft Plastic Fishing Lure Molds for DIY Tackle

Table of Contents

1. Introduction
2. Why Make Your Own Lure Molds?
3. Choosing the Right Mold Material
4. Essential Tools and Safety Equipment
5. Step 1: Preparing the Mold Box
6. Step 2: Making a Plaster of Paris Mold
7. Step 3: Making an RTV Silicone Mold
8. Step 4: Heating and Preparing the Plastisol
9. Step 5: The Pouring Technique
10. Troubleshooting Common Issues
11. Advancing Your Skills
12. Summary Checklist for Lure Making
13. Conclusion
14. FAQ

Introduction

Every angler has a favorite lure that just seems to pull fish when nothing else works. The problem starts when that specific bait is discontinued or becomes too expensive to lose in heavy cover. Learning how to make soft plastic fishing lure molds allows you to replicate your most successful patterns at a fraction of the retail cost. At BattlBox, we believe in the value of self-reliance, and crafting your own gear is a natural extension of that mindset. If you want to keep building that mindset, choose your BattlBox subscription. This guide covers the materials, safety protocols, and step-by-step techniques for creating durable lure molds from scratch. By the end of this article, you will understand how to turn a single "hero" bait into a lifetime supply of custom tackle.

Quick Answer: You can make soft plastic fishing lure molds using Plaster of Paris, RTV silicone, or high-temp resin. The process involves placing a master lure in a mold box, pouring your chosen material over it, allowing it to cure, and then removing the master to leave a perfect cavity for liquid plastisol.

Why Make Your Own Lure Molds?

The primary reason most fishermen look into mold making is cost. Premium soft plastics often cost over a dollar per bait. If you fish in areas with snag-heavy brush or toothy species like pike, you can go through a bag of lures in a single afternoon. Making your own molds brings that cost down to pennies per lure, and it pairs well with our Fishing collection.

Beyond the money, there is the advantage of customization. When you control the mold, you control the finished product. You can create unique color laminates, adjust the density of the plastic for different sink rates, or add specific scents that aren't available in stores. This level of control is a significant advantage when fish are being picky about their presentation.

Finally, there is the satisfaction of the craft. Catching a personal best on a lure you designed and poured yourself is a highlight of the sport. It deepens your understanding of lure action and fish behavior.

Choosing the Right Mold Material

Before you start building, you need to decide which material fits your needs. Most DIY lure makers choose between three main options: Plaster of Paris, RTV silicone, and resin.

Plaster of Paris (POP)

This is the most affordable entry point for beginners. It is easy to find at any hardware store and very simple to mix. The downside is that plaster is porous. You must dry it completely and seal it with an epoxy or high-temp coating before you can pour hot plastic into it. Without sealing, the moisture in the plaster will turn to steam and cause bubbles in your lures.

RTV Silicone

RTV stands for Room Temperature Vulcanizing. This is a two-part rubber that cures into a flexible, heat-resistant mold. Silicone is excellent for lures with complex shapes or deep undercuts because the mold can stretch to release the bait. It requires no sealer and produces a very high-gloss finish on the final product.

Resin and Aluminum

High-temperature resins are more durable than plaster but less flexible than silicone. They are great for high-volume pouring. Aluminum molds are the gold standard, usually created via CNC machining. While you can cast aluminum molds at home, it requires a much more advanced setup and is generally beyond the scope of a standard DIY garage project.

If you want a related DIY angle, our guide to making fishing lure molds is a helpful companion.

Essential Tools and Safety Equipment

Working with hot liquid plastic, known as plastisol, requires respect for the materials. Plastisol is a PVC-based liquid that turns into a soft solid when heated to approximately 350 degrees Fahrenheit. At these temperatures, it can cause severe burns if it touches your skin.

Safety Gear Checklist:

• Respirator: Liquid plastisol releases fumes when heated. Always wear a respirator with organic vapor cartridges.
• Safety Goggles: Protect your eyes from accidental splashes or "burps" in the heating cup.
• Heat-Resistant Gloves: Heavy leather or silicone gloves are necessary when handling hot glass measuring cups.
• Long Sleeves: Even in summer, keep your skin covered to avoid direct contact with hot plastic.
• Ventilation: Work in a garage with the door open or use a high-powered exhaust fan.

Required Tools:

• Dedicated Microwave: Never use the same microwave for food and lure making.
• Glass Measuring Cups: Use Pyrex or similar heat-tempered glass. Do not use plastic.
• Mixing Spoons: Metal spoons are best. Avoid wood, as it holds moisture and creates air bubbles.
• Infrared Thermometer: Essential for checking the temperature of the plastic without touching it.

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Key Takeaway: Safety is the most important part of this process. Molten plastisol sticks to the skin like napalm, so never skip the protective gear or the dedicated ventilation.

Step 1: Preparing the Mold Box

The first step in making a mold is creating a container to hold your molding material. This is called a mold box. You can use old plastic food containers, or you can build a custom box using foam board and hot glue.

How to set up the mold box:

1. Select a container slightly larger than the lure you want to copy.
2. Ensure the bottom of the container is flat.
3. Secure the "master" lure to the bottom. Use a small amount of super glue or double-sided tape.
4. If the lure is round, you may need to build a two-part mold. For beginners, start with a flat-back lure (like a fluke or a craw) to make a one-part "open pour" mold.

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Note: If your master lure is made of soft plastic, make sure it is clean and dry. Any oil or dirt on the master will show up in the final mold.

Step 2: Making a Plaster of Paris Mold

Plaster is the best way to learn the basics without spending much money. It is forgiving and allows you to experiment with different lure shapes.

The Mixing Process: Follow the manufacturer's instructions for the ratio of water to plaster. A common ratio is two parts plaster to one part water by weight. Stir slowly to avoid introducing air bubbles. The consistency should be like thick pancake batter.

The Pour:

1. Slowly pour the plaster into one corner of your mold box.
2. Let the plaster flow around the lure rather than dumping it directly on top. This helps prevent air pockets from getting trapped in the lure's details.
3. Gently tap the sides of the box or vibrate the table to help air bubbles rise to the surface.
4. Let it sit for at least an hour until it feels hard and cool to the touch.

Curing and Sealing: Once the mold is hard, remove the master lure. The mold will still contain moisture. You can let it air dry for a week, or speed up the process by placing it in an oven at 200 degrees Fahrenheit for two hours. Once dry, coat the inside of the cavity with a high-temp epoxy or a dedicated mold sealer. This gives the final lure a professional, glossy finish.

For more on the mold-building side, see How to Make Plastic Fishing Lure Molds.

Step 3: Making an RTV Silicone Mold

If you want the best possible detail and a mold that lasts for hundreds of pours, silicone is the way to go. We often see high-quality silicone components in our emergency gear because the material is so resilient.

The Mixing Process: RTV silicone usually comes in two parts. You must mix them accurately, often by weight or volume (usually a 1:1 or 10:1 ratio). Mix thoroughly for several minutes, scraping the sides of the container.

The Pour:

1. Pour the silicone in a very thin stream into the lowest point of the mold box.
2. The thin stream helps pop any bubbles created during the mixing process.
3. Fill the box until the lure is covered by at least half an inch of silicone.
4. Let the silicone cure for the time specified by the manufacturer (usually 6 to 24 hours).

Unlike plaster, silicone does not need to be sealed. Once it is cured, it is ready for the first pour of plastisol.

Bottom line: Plaster is great for learning and budget projects, while silicone offers professional-grade detail and flexibility for complex lure shapes.

Step 4: Heating and Preparing the Plastisol

Once your mold is ready, it is time to prepare the soft plastic. Liquid plastisol looks like milk when it is cold. As it heats up, it will turn into a thick gel and then eventually into a clear, runny liquid.

The Heating Process:

1. Pour the liquid plastisol into your glass measuring cup.
2. Heat in the microwave for one minute.
3. Remove and stir with a metal spoon.
4. Continue heating in 30-second intervals, stirring between each.
5. Check the temperature often. You are looking for a range between 325 and 350 degrees Fahrenheit.

Adding Color and Glitter: Once the plastic is clear and liquid, you can add your pigments. Start with just a few drops; a little goes a long way. After the color is mixed, add your glitter. If you add glitter to cold plastic, it may sink to the bottom or lose its color during the heating process. Adding it at the end ensures the best look.

If you want more foundational lure-making guidance, How to Make Fishing Lures: A Practical Supply Guide is a useful next step.

Step 5: The Pouring Technique

Pouring the plastic into the mold is where the "art" of lure making happens. It requires a steady hand and a bit of patience.

Steps for a Clean Pour:

1. Prep the Mold: If using a plaster mold, apply a very light coat of worm oil or vegetable oil to help the lure release. Silicone molds usually don't need this.
2. The Initial Pour: Start at the "head" of the lure. Pour a thin, steady stream.
3. Filling the Cavity: Move the stream slowly toward the tail. Fill the mold until the plastic is slightly higher than the top of the cavity. This is called "crowning." As the plastic cools, it will shrink slightly.
4. Wait for Cooling: Let the bait sit for several minutes. If you pull it out too early, the lure will deform or stretch.
5. De-molding: Gently peel the lure out of the mold. If it sticks, use a little more oil next time.

Myth: You can use any plastic container to heat your plastisol. Fact: Most plastics will melt or leach chemicals at 350 degrees. Always use tempered glass like Pyrex to ensure safety and clarity in your lures.

Troubleshooting Common Issues

Even experienced lure makers run into problems. Most issues are caused by temperature or moisture.

Bubbles in the Lures

If your lures look like Swiss cheese, you have air or moisture in the system. Ensure your mixing spoon is metal and dry. If using plaster, ensure it is fully sealed. You can also let the hot plastic sit for a few seconds after stirring to let the air bubbles rise to the surface before you pour.

Lures Tearing

If the lure breaks when you pull it out of the mold, you might be using "hard" plastisol for a delicate shape. You can buy "softener" additives to make the plastic more flexible. Also, ensure the mold is completely cool before you attempt to remove the bait.

Colors Bleeding

If you are pouring two-color baits and the colors are mixing, you are pouring the second color too soon. Wait about 45 to 60 seconds between colors. The first color should be firm to the touch but still hot enough to bond with the new plastic.

If you want a broader look at tackle selection, Top Must-Have Fishing Lures for Every Angler’s Tackle Box pairs well with this stage of the process.

Advancing Your Skills

Once you master the basic open-pour mold, you can move on to more advanced techniques. These include two-part molds for fully round baits and injection molding.

Two-Part Molds

A two-part mold allows you to create lures like round worms or tubes that have detail on all sides. This involves pouring one half of the mold, letting it cure, and then pouring the second half over the top. You must use a "mold release" agent between the two halves, or they will fuse together permanently.

Injection Molding

In this process, you use a large metal syringe called an injector to force hot plastic into a clamped, two-piece mold. This is the method used by professional manufacturers. It allows for incredibly complex shapes and perfectly consistent results. Many of the high-quality tools we curate for our subscribers involve this level of precision engineering.

For a related look at the bigger lure-making process, How to Make Your Own Plastic Fishing Lures is a great follow-up read.

Summary Checklist for Lure Making

If you are ready to start your first project, keep this checklist handy to ensure you don't miss a step:

• Set up a dedicated, well-ventilated workspace.
• Wear a respirator, goggles, and gloves.
• Secure your master lure in the mold box.
• Mix and pour your mold material (Plaster or Silicone).
• Allow the mold to cure and seal it if necessary.
• Heat your plastisol to 350°F in a dedicated microwave.
• Add pigment and glitter only after the plastic is clear.
• Pour slowly from head to tail.
• Let the bait cool completely before removing.

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Conclusion

Mastering how to make soft plastic fishing lure molds is a skill that pays dividends every time you hit the water. It transforms a consumable item into a renewable resource and gives you a level of customization that the big-box stores cannot match. Whether you are prepping for a long season on the lake or simply looking to expand your outdoor self-reliance skills, DIY tackle making is a productive and rewarding hobby. At BattlBox, our mission is to provide the gear and knowledge that help you feel more capable in the wild. By building your own gear, you are taking the next step toward becoming a truly self-sufficient outdoorsman.

Key Takeaway: Success in lure making comes from controlling the variables—temperature, moisture, and timing are the keys to a professional-looking bait.

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FAQ

Can I melt down old, used lures to make new ones?
Yes, you can recycle old soft plastics by cutting them into small pieces and heating them in the microwave. Be aware that different brands use different formulas, so mixing them might result in strange textures or unexpected colors. Always remove any dirt or salt from the old lures before melting them down to ensure a clean pour.

Is making your own fishing lures safe?
It is safe as long as you follow strict safety protocols. The two biggest risks are burns from 350-degree plastic and inhaling fumes from overheated plastisol. Always wear a respirator, use a dedicated microwave in a well-ventilated area, and wear protective clothing to prevent skin contact with the molten liquid.

How long do DIY soft plastic molds last?
A well-made RTV silicone mold can last for hundreds of pours if handled with care. Plaster of Paris molds are more fragile and may begin to chip or crack after 20 to 50 pours, depending on how well they were sealed and how carefully you remove the lures. Aluminum molds are essentially permanent and will last a lifetime.

What is the best way to add scent to homemade lures?
You can add oil-based scents directly into the hot plastisol before pouring, or you can "marinate" the finished lures in a bag of scented worm oil. Adding scent to the hot plastic ensures it is distributed throughout the bait, while soaking the finished lures provides a strong initial scent trail in the water.

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