Tackle Care · Materials
You open the lure box after a fortnight in the garage. Half the compartments have gone cloudy. Two lures that were definitely separate are now one lure. Something has gone sticky, and there’s a smell that wasn’t there before.
Everyone assumes the box has failed. It usually hasn’t. The lures did it to each other.
It’s not just heat, and it’s not necessarily the box
The reflex explanation is that the box got hot in the car. Heat can accelerate the process significantly, but incompatible soft plastics can affect one another even at normal storage temperatures. This happens to boxes that live in a cool shed.
What’s actually going on is material incompatibility, and once you understand it the whole problem becomes obvious and easy to avoid.
Two different materials, sold as the same thing
Most soft lures anglers encounter are based on either conventional plasticised PVC or one of several TPE formulations, and the packaging rarely tells you which.
Plastisol starts as fine PVC resin dispersed in liquid plasticiser. Heating causes the PVC to gel and fuse, producing a flexible plasticised PVC material in which the plasticiser stays mobile within the polymer. The ratio is what makes it soft — change it and you go from rock hard to almost liquid. It’s what I use for every Maverick Tackle lure, and it’s what most established soft plastic brands use too.
TPE, thermoplastic elastomer, isn’t one material — it’s a broad family of polymers. The ones this article is about are the very soft, highly elastic grades used for stretchy lures, usually styrenic types such as SEBS. These get their softness from a combination of molecular structure and, in many cases, substantial quantities of process or plasticising oil. Chemically they’re a long way from plasticised PVC. They’re rubbery, often tougher, and a lot of the newer micro lures are made from them.
They look identical in the packet. They behave completely differently in a box.
The bit nobody tells you
The plasticiser in plastisol doesn’t stay locked inside the lure. It slowly works its way to the surface and out. That faint oiliness on a plastisol lure that’s been bagged for a while can partly result from plasticiser and other mobile additives reaching the surface. Many soft TPE lures carry mobile process oils of their own, which behave the same way.
Where two formulations are incompatible, those low-molecular-weight components migrate between them. The receiving material can swell, soften or become tacky as mobile additives move across, and can eventually lose its shape entirely. That’s the melting — not one material dissolving the other so much as their mobile additives going where they shouldn’t.
Separate compartments may not be enough
This is the part that catches people out, and it’s why “I keep them apart” isn’t always the whole answer.
Direct contact is the clearest and fastest route. But some plasticisers are semi-volatile, meaning they can enter the gas phase, so transfer within a closed container is possible in principle. In a typical tackle box the compartments share the same enclosed headspace unless they are individually sealed. A divider prevents physical contact, but it is not a gas-tight barrier.
I’ve had TPE go tacky in a compartment three across from the nearest plastisol lure. That’s my own observation, and on its own it doesn’t prove airborne transfer was the cause — something else in that box may have been responsible. It’s exactly why I’m running the jars.
And the box material can matter too
Plasticisers and other additives can migrate into some polymers in contact with them, although how much depends heavily on both the additive and the material the box is made from.
If a box has visibly softened, clouded or gone tacky after long-term soft-plastic storage, I wouldn’t then trust it for an incompatible TPE formulation. A box sold as worm-proof or soft-plastic compatible is the safer choice.
Testing this properly
I’m running a controlled experiment on this at the moment, to separate direct contact from shared air. Identical TPE lures from the same pack, in sealed jars: one in direct contact with plastisol, one suspended in the same sealed air but never touching, one isolated TPE control, and an isolated plastisol control. Dated photographs throughout. The result will be published whichever way it goes.
What actually works
Two boxes, permanently
One for plastisol, one for TPE, and they never swap roles. Label them if you have to. This single change solves most of the problem.
Keep them in their original bags
The original bag is designed to be compatible with that particular lure formulation. Leaving lures in it also prevents direct contact with unknown materials, making original packaging the safest option when you’re unsure.
Use a worm-proof box
Go by what the manufacturer claims rather than by guessing at the polymer: boxes sold as worm-proof or soft-plastic compatible stand up to plasticiser far better than cheap clear ones that crack when you drop them. PE and PP-type materials are commonly used for this because of their chemical resistance, but the compatibility claim is what matters. It’s not a licence to mix materials, but it stops the box itself going soft and cloudy.
Don’t store them in the car
Heat accelerates everything above. A boot in August is the worst place in your life for a lure box.
Bin the ones that have gone
A lure that has badly swollen, deformed or become tacky is unlikely to recover fully, and it can contaminate whatever it’s next to.
If you’re not sure which you’ve got
Plastisol has a slight oily feel and a distinct smell — most people recognise it instantly once they’ve handled a few. Smell alone doesn’t tell you what’s migrating, mind: scents, oils and other volatile additives all contribute. Some plastisol formulations also become firmer or cloudier at low temperatures. TPE feels drier, more rubbery, and springs back harder when you stretch it. These are useful clues rather than definitive identification tests — formulations vary, and appearance or feel alone cannot reliably identify the polymer.
If you genuinely can’t tell, keep it in its original packaging — that’s the safest option for an unknown formulation. Conventional plastisol lures are generally compatible with other conventional plastisol lures, though dyes, scents and oils can still migrate between them, and the same caution applies to TPE: different grades use different polymers, oils and additives, so don’t assume two stretchy lures are automatically happy together. Highly stretchy, oil-extended TPE lures are particularly worth keeping away from conventional PVC plastisol unless the manufacturer states they’re compatible.
The short version
Your box isn’t faulty and your lures aren’t badly made. You’ve most likely mixed two incompatible formulations, and their mobile additives are migrating between them.
Keep known incompatible TPE and plastisol apart, leave unknown lures in their original packaging, and don’t assume a compartment divider guarantees chemical isolation. That’s the whole answer.
Technical note — 3 September 2026: An earlier version of this article described TPE as containing no plasticiser of its own. That was too broad. Many very soft styrenic TPE compounds contain substantial quantities of process or plasticising oils. The article has been updated to describe the interaction more accurately.
Every Maverick Tackle lure is conventional plastisol, injected and finished by hand in the Cotswolds. They are generally compatible with other conventional plastisol baits, although original packaging remains the safest option for long-term storage. mavericktackle.com