TPE vs Plastisol: 41 Days in Sealed Jars — Here’s What Happened

Tackle Care · Materials · The 41-Day Test

This is a follow-up to Why Your Soft Plastic Lures Melt Into Each Other.

Why I ran the test

In the first article I looked at what happens when some highly stretchy TPE-type lures are stored with conventional soft-plastic plastisol. The direct-contact problem is real: put incompatible materials together and you can end up with swelling, softening, distortion or the familiar sticky, fused mess anglers often describe as the lures “melting”.

But I had also seen TPE lures become tacky in a tackle box without any obvious direct contact with the plastisol stored nearby. That raised a more interesting question:

Was physical contact actually necessary, or could something migrate through the shared air inside a closed box and affect the TPE anyway?

Some additives used in soft plastics are mobile and some are semi-volatile, so gas-phase transfer is possible in principle. But “possible” is not the same as showing that enough transfer takes place inside a tackle box to damage a lure. Rather than keep speculating, I decided to test it.

The setup

I started the experiment on 30 August 2026 using three samples from the same lure, same colour and same packet.

The lure was a generic, highly stretchy cicada-style TPE-type bait bought from one of the usual Far Eastern online marketplaces. That choice was deliberate. An angler who ends up mixing an unknown stretchy lure with conventional soft plastics is probably more likely to be using an inexpensive mass-market bait like this than a high-end German-made or other specialist European elastomer formulation supplied with a detailed technical data sheet.

I do not have the exact polymer specification or full additive package for this lure. That means I cannot claim that the result represents every TPE, TPS or other elastomer formulation. A specialist formulation from another manufacturer may behave differently. The point here was to test a realistic product of the kind anglers actually put in ordinary tackle boxes.

For the plastisol I used normal Maverick Tackle injection by-products — sprues and offcuts from lure production — cut into small pieces. They came from several colours, but were all conventional lure plastisol from my normal production process.

The test had three conditions:

• Control: TPE sealed in an otherwise empty jar.
• Suspended: TPE hung above plastisol pieces inside the same sealed jar, sharing the same enclosed airspace but never touching them.
• Contact: TPE placed directly on the plastisol pieces.

The experiment in photographs

The photographs below follow the experiment from the initial setup to the final comparison. The captions use the timings I can confirm; I have not assigned exact dates to the other intermediate photographs. The experiment began on 30 August and the jars were finally opened and assessed on 10 October.

The first result came quickly

The direct-contact sample did not take long to react.

Within roughly 24 hours I could already see visible change where the stretchy lure was sitting against the plastisol. As the experiment continued, the affected area became progressively softer-looking and more distorted.

That part of the result was not subtle. This particular mass-market TPE-type lure and my conventional plastisol were clearly incompatible when kept in direct contact.

Forty-one days later

I left the samples sealed from 30 August until 10 October 2026 — 41 days — before making the final comparison and checking the samples by touch.

The visual result was clear. The direct-contact sample had reacted substantially. The lure suspended above the plastisol still looked essentially the same as the isolated control.

What about tackiness?

Photographs could answer the obvious visual question, but not the final one:

Had the suspended TPE become tackier even though it still looked normal?

When I compared the suspended sample directly with the control, both were slightly tacky — which is how this particular TPE-type material feels anyway.

I could not detect any difference in tackiness between them.

The suspended lure was not noticeably stickier, softer or otherwise different from the isolated control.

After 41 days, sharing the same sealed airspace with plastisol produced no visible or detectable change in the suspended TPE sample compared with the isolated control.

The result at a glance

So was the “airborne plasticiser” theory wrong?

For this experiment, I found no evidence that shared airspace alone was enough to damage the lure.

That does not prove that absolutely no molecules moved through the headspace. This was not a chemical-analysis experiment and I did not measure vapour concentrations. What it shows is more practical: under these conditions, with this particular TPE-type lure and this plastisol, any gas-phase transfer that may have occurred was not enough to produce a visible or tactile effect after 41 days.

Meanwhile, direct contact produced an obvious reaction within about a day.

Direct material-to-material contact was overwhelmingly the important factor in this test.

And that changes one of my earlier conclusions

In the original article I discussed gas-phase transfer as one possible explanation for TPE becoming tacky even when it appeared to be stored several compartments away from plastisol.

This experiment did not reproduce that.

So I would no longer present shared airspace as the likely explanation for that earlier observation without more evidence.

There are several other possibilities. The lure may have touched plastisol previously. Oils or additives may have been transferred by hands, tools or other tackle. The box itself may have been contaminated. Or a completely different combination of TPE and plastisol may behave differently.

The correct answer at this stage is simply: I do not know what caused that earlier observation. The jar test gives me no reason to blame shared airspace alone under the conditions I tested.

What this experiment does — and does not — prove

This was a practical controlled demonstration, not a replicated laboratory study. There was one sample in each condition, and I do not have a laboratory analysis of the lure formulation.

So it would be wrong to turn the result into “all TPE is safe in separate compartments” or “all plastisol reacts with all TPE”. TPE covers a large family of materials, and manufacturers can use very different polymers, process oils, plasticisers and other additives. Plastisol formulations vary too.

What I can reasonably say is:

• This particular mass-market TPE-type lure was strongly incompatible with my conventional lure plastisol in direct contact.
• The first visible reaction appeared within about 24 hours.
• An identical sample from the same lure showed no visible effect after 41 days sharing the same sealed airspace with the plastisol without touching it.
• At the final tactile comparison, the suspended sample had the same slight natural tackiness as the isolated control.

What does this mean for your tackle box?

The practical lesson is much simpler than the chemistry:

Do not let an unknown stretchy TPE-type lure sit directly against conventional plastisol.

If you know a lure is made from one of these highly stretchy materials and the manufacturer recommends keeping it in the original packet, that remains the safest option.

This test also gives me more confidence that a physical divider can be useful because it removes the direct-contact route that caused the obvious damage here. But I would not treat one experiment as proof that every possible lure formulation is safe in every compartmented box.

If you do not know what a bait is made from, keeping it in its original packaging remains the simplest rule.

The result in one sentence

The TPE sample touching plastisol began visibly reacting within about 24 hours; the identical sample sharing the same sealed airspace without contact showed no visible or detectable difference from the isolated control after 41 days.

Sometimes a test confirms what you expected. Sometimes it knocks down part of your own theory.

This one did both — which is exactly why it was worth doing.