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Gas cap lanyard – Improvements and testing #2. Chemical resistance.

Updated: May 30

Gas cap lanyard – Improvements and testing #2. Chemical resistance.

This blog series applies to both versions of the lanyard I sell:

I covered the design changes and improvements that were made to the replacement gas cap lanyard in order to make it better than the OEM version.

The next most common question I get is, “What happens if gas spills on it?”

The answer is pretty boring. But getting to the answer was kind of fun and a little bit dangerous.

Cliff notes – The answer is:

Nothing. Spilling gas on it doesn’t seem to affect the lanyard at all.

OK, you're still reading! On with the show!

Wikipedia, Google and most of the rest of the internet tells us that the lanyard material, Thermoplastic Polyurethane (TPU), has excellent resistance to many chemicals including hydrocarbons (gasoline). That’s great news. But what does it actually mean in real life?

It means it’s time to test what we’ve been told. Lets stick a lanyard in a bunch of gasoline and see what happens.

On July 14, 2017 at approximately 11:37 am I began the scientific stick a lanyard in a bunch of gas experiment. I placed a grey lanyard in a transparent cylindrical container and then carefully sloshed in a precisely measured quantity of questionable casino gas station 87 octane pump gasoline (may contain up to 10% ethanol).

Day one – Nothing happened.

Day two – The sharpie markings wore off.

Day three – Maybe we need more gasoline in the jar.

I intended to check it every day, but honestly I got bored after a few days and checked it when I remembered. The most interesting thing that happened is that the Tupperware cylinder of science started to discolor.

This went on uneventfully until August 5th, 2017. Dun Dun Dun!!!

On August 5th I was bored enough watching the Replacement Lanyard do nothing it was finally time to see how the OEM lanyard material reacted to gasoline.

Fortunately there was an another cylinder of science in stock at the laboratory. This one previously held Parmesan cheese. I rinsed it out but didn't really wash it that well since there was imminent science-ing to do!

Unfortunately the laboratory was out of stock of questionable casino gas station gasoline (may contain up to 10% ethanol). It had all been recently donated to mowing the lawn. We'll have to use ethanol free 92 octane for this experiment.

And now?!

Turns out the OEM lanyard is about as boring as the Replacement lanyard.

Day one – Nothing happened.

Day two – Nothing happened.

Day three – Maybe we need more gasoline in the jar.

Fast forward a bit-

On September 10th I pulled the lanyards out of the gasoline and did some physical testing. The Replacement lanyard is still pliable and stretchy. Other than a little bit of yellowing and reeking of gasoline, there's no noticeable change. The OEM lanyard, pretty much the same story, no noticeable change after being immersed in gasoline.

OK, it's now obvious this is going to turn into a much longer term experiment than expected. It's time to combine the replacement lanyard and the OEM lanyard into the same jar.

Next steps?

We wait some more...

OK, fine. Both test samples are still in the jar to this day. I add gas every now and then as it evaporates. Yes this is somewhat dangerous. The gas has eaten the seal material on the pickle jar lid (AKA cylindrical container of science) so it doesn’t seal as well as it used to. I'm not 100% comfortable letting this experiment marinate more but it's currently sits next to the gasoline container I use for the lawn mower and that hasn't burst into flames yet so we should be moderately safe...

If you’re wondering why I seem to do most of the testing with grey lanyards, it’s because that’s the color I sell the least amount of so there’s usually one around I can grab that’s not going to a customer.

Disclaimer/word of caution/ymmv/etc/?! - If you have gasoline pooling in the gas cap area you have a serious problem with your vehicle, please get that fixed before considering purchasing a replacement gas cap lanyard.

Onto the pictures -

Replacement Gas Cap Lanyard Testing:

OEM Lanyard testing:

Combined OEM and Replacement into a glass jar:

(If you're curious, they're awesome spicy pickles, get them here: (affiliate link))

Results after 3 months immersed in gasoline:

Current picture of the cylinder of science as of 8:19pm December 3, 2017

(Yes, another crappy cell phone pic, sorry. But it's cold and getting late so that's the best we get tonight...)

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