Will a Flask Set Off a Metal Detector? The Expert Answer

  • By: Chris
  • Last updated on November 17, 2022
  • Time to read: 6 min.
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Welcome back! While I tend to focus on answering questions for the metal detecting crowd, I can’t ignore the needs of the many.

Yes, that’s you.

Rather than watch you stumble into a no-win situation, I thought it best to use my experience and metal detector knowledge to help you in this time of need.

Because of their electrical conductive properties, any flask made of metal will set off a metal detector.

But not every flask is made of metal, is it?

So, as I’ve done with other forms of contraband, like vapes, let’s dig into what you can expect.

What Is the Point of A Flask?

what is the point of a flask
Why use a flask? They’ve been used for centuries in one form or another.

What’s the point of a flask, you say?

Well, assuming it’s your flask, you should already know. But just in case, I’ll tell you.

Flasks are carrying receptacles for alcohol initially meant to be used for discreet transportation and consumption.

The flask’s original design was intended to make drinking during prohibition safe and obscure.

But today, using a flask is a stylish way to enjoy a drink for special occasions or when a night on the town requires some extra flare.

Just don’t be that person that breaks out the flask at a bar.

How Many Shots Are in A Small Flask?

how many shots are in a small flask
Don’t worry. The math isn’t that complex.

Flasks come in several sizes, 6 fluid ounces being the most common. However, a small 4 oz flask can hold the equivalent of 4 shots of alcohol.

So, if your sole purpose for bringing along a small flask is to get drunk, you’ll want to consider other options or choose a full-bodied liquor.

What Metal Is Used for Flasks?

As I said, if your flask is made of metal, it will most certainly set off a metal detector. 

There’s a lot of science behind it. And I won’t bore you will all the details here. 

what metal is used for flasks
You could use any metal to create a flask. But stainless steel is the most popular.

In essence, it has to do with the disruption of the magnetic field generated by a metal detector. The ‘disruption’ source is the metal object’s responding electromagnetic field.

If you’re interested in a deeper explanation, jump over to my article on how metal detectors work.

But, getting back to your concerns, the metal used to make your flask is likely stainless steel or pewter.

These metals are used because both offer a classic and appealing style, can be made into various shapes and sizes, and are corrosive resistant.

Even better, after the initial cleaning, you don’t get that nasty metallic taste in your drink with stainless steel and pewter.

The only downside to pewter is it’s more prone to damage than stainless steel, specifically in the form of dents and scratches.

Will a Stainless Steel Flask Set Off a Metal Detector?

will a stainless steel flask set off a metal detector
Stainless steel has enough electrical conductivity to set off a metal detector.

If you’ve read any of my other articles on what a metal detector can and cannot detect, you know some metals are more conductive to electricity than others.

Stainless steel flasks, while not the most conductive, will still be able to set off a metal detector. Its electrical conductivity measures around 1.4 million siemens per meter at room temperature.

“Siemens is a unit of electrical conductance, defined as 1 divided by ohms, where an ohm is a standard unit of electrical resistance”.

James A. Inglehart

That’s a lot of technical jargon. But, the critical fact is metal detectors won’t have any trouble detecting stainless steel.

If your flask is made of pewter, the likelihood of setting off a metal detector will increase.

pewter is more conductive than stainless steel
Pewter isn’t as durable as stainless steel but a better conductor of electricity.

Compared to the 1.4 million siemens of stainless steel, tin, which makes up about 91 percent of pewter, has an electrical conductivity measurement of 9.17 million.

For a look at how other metals stack up, check out this conductivity table created by ThoughtCo.

Do They Make Plastic Flasks?

You may have seen them around. Maybe on a cruise ship or at a concert. But plastic flasks are made to offer a safe way to transport liquid while avoiding the alarm of a metal detector.

Just be careful which plastic flask you intend on using.

do they make plastic flasks
Plastic flasks are favored worldwide for travel, concerts, and other events.

I’ve seen my share of plastic flasks that boast elusive materials from metal detection, even with an aluminum shot-style cap. 

Sorry to break it to you, but aluminum can’t hide from metal detectors, despite the rumors.

You’ll have many options if you go with a genuine all-plastic flask. Some look like clear juice pouches, while others are sleeker-looking and made from high-quality, durable Tritan plastic.

No matter your choice, as long as it’s really metal free, your plastic flask with go undetected.

Should I Use Glass Flasks for Liquor?

should i use glass flasks for liquor
You could use a glass flask, but you have to worry about cracking, chipping, and breaking.

You could use a glass flask, but plastic is safer. 

Unless you cover the glass flask with a protective silicone or leather sleeve, you risk breaking it with a mild case of butterfingers.

And even if you use a sleeve, it’s far more noticeable when trying to hide the bulkiness under your jacket.

As far as glass and metal detectors go, glass contains no metal properties and has no conductive effects to set off a metal detector.

If you opt for a glass flask, just confirm the cap isn’t made of metal.

How to Hide a Flask

how to hide a flask
You can hide a flask best by choosing one with an appropriate material.

Hiding a flask is simple.

Physically speaking, a flask is small enough to conceal in your back pocket or attached to your hip while wearing a long shirt or jacket.

As long as you aren’t subject to a pat-down, most flasks will go unseen thanks to their curved shape and ability to hug against your body.

How to Get a Flask Through a Metal Detector?

how to get a flask through a metal detector
You better use a plastic flask to get through a metal detector alarm-free.

When getting a flask through a metal detector, use a flask made of plastic or glass. Both of these have no magnetic properties, so security is a breeze.

Using a metal flask all but guarantees you’ll get caught. 

Most walk-through metal detectors have a high enough sensitivity to detect the combined magnetic fields of a belt buckle, brass buttons, and some loose change.

Sometimes, the belt buckle alone is enough to set it off.

How Do You Sneak a Flask Into a Stadium?

how do you sneak a flask into a stadium
Get creative, choose a proper container, and don’t get caught.

Not that I support these trickier methods or any of them, but there are plenty of ways to get your alcoholic beverage into a stadium or concert.

Besides using a standard plastic flask, you could use a flask made to look like some other harmless personal item.

I’m not joking.

I discussed some of these possibilities in my article about getting a beer can into a concert.

But imagine containers that look like hairbrushes, binoculars, or tampons to give you a brief illustration.

Again, I’m not joking.

im not joking tip of the iceberg
Believe it or not, plenty of unique and unbelievable methods exist to conceal a flask.

That’s just the tip of the iceberg, to be frank.

Your options are limited only by your imagination.

Round Up Before You Go

I hope I was able to give you the answers you needed. And, at a minimum, prevented you from an uncomfortable situation at the security gate.

Remember, if your flask has any trace of metal, it’ll set off a metal detector 9 times out of 10.

And that 1 time it doesn’t is probably a fluke or a poorly calibrated metal detector.

Either way, you got lucky.

So, good luck with your adventure! Drink responsibly, and do your best to stay out of trouble.

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