The Legend of Oppenheimer's Hat

The Legend of Oppenheimer's Hat

The Hat That Ruined All Hats.

The Iron Snail Clothing Company

Ellen Mirojnick, the Oppenheimer 2023 movie costume designer, had to commission 3 expert hat makers to recreate the hat before they got it right. 

What is it about Oppenheimer’s hat that baffled some of the world’s best hat makers? Why did everyone wear hats during Oppenheimer’s time and what stopped them from wearing hats after WWII?



Table of Contents

  • Identifying and recreating Oppenheimer’s hat.

  • How was Oppenheimer’s hat made?

  • What makes these hats virtually indestructible?

  • Why hats fell out of fashion after WWII.

What hat did Oppenheimer wear?

  • The origin: Texas, mid 1800’s

  • Stetson: The company that invented the cowboy hat

  • Oppenheimer’s fidgeting make his hat hard to identify

It might not look like it, but the hat Oppenheimer wore during his lifetime was likely the The Stetson Deluxe Open Road Hat. A hat, funny enough, that started off as a joke between hunting buddies. Let’s discuss why.

John B. Stetson made a hat while on a hunting trip with his friends. He was demonstrating how to make what is now known as the original Stetson fabric, one that required no knitting or weaving.  The norm for hat’s back then were smaller and sleeker, but Mr. Stetson made his hat comically large to be silly.  

John B. Stetson

Over time, he realized how convenient it was to have a wide brimmed hat for sun and protection. The hat also proved to have great insulation properties from the air pocket that the hat creates on the top of the head. The hat he made also proved to be waterproof, with the water beading off of it in the rain. 

Now, Mr. Stetson wasn’t the first person to create a hat made out of the specific materials that he used. In fact, acquiring one of the main materials was already a major business all around the world. He did, however, turn these types of hats into an American icon. But you may not recognize it yet…

The story goes that a cowboy approached Mr. Stetson and his friends on this hunting trip and offered to buy Stetson’s hat for a $5 gold piece, thus beginning the empire of Stetson hats.

The Boss of the Plains Hat was the first hat of its kind produced by Stetson and it sold like wildfire. The Open Road Hat was introduced in 1937, which would mean it could reasonably be Oppenheimer’s hat! 


Fun Fact: While these both are staples of the Stetson line and many may consider them to be American icons, they aren’t THE iconic American hat that Stetson eventually created.

Did you know? When purchasing a Stetson hat, they will steam it to your liking. If you steam a hat made out of the unique materials that Stetwon uses (more on those later) and you shape the hat while it’s being steamed, it’ll hold that shape once it dries. So, if we steam The Boss of The Plains hat, add some indents to the crown and curl the sides of the brim up, we get the icon: The American Cowboy hat, the hat of the West. From John Wayne, to Jake Gyllenhal, this hat is as iconic as blue jeans and the Ford Model T.

Source: American Hat Makers 


People speculate that Oppenheimer got his hat in New Mexico because he spent a lot of time there, but many believe it is the Boss of the Plains or the Open Road hat by Stetson. But, it doesn’t look like either of these hats. Why?

Apparently, Oppenheimer was a fidgety guy who chain smoked during lectures, forgot to eat, almost poisoned his tutor, and needless to say, probably fiddled with his hat a lot when he was wearing it. This means the brim of the hat would have gotten bent out of shape and the crown would have been reshaped from him pressing the edges in with his fingers.


How was Oppenheimer's hat made?

  • Natural fibers

  • A special non-weaving technique

  • Unique animal fur 

Hats of this time were not knitted or woven together. Instead, they were created with fibers being pressed together very densely, starting with a very large cone of matted fibers that are then pressed/agitated until the cone becomes regular sized with extremely dense, locked-together fibers that could be shaped into a hat.

This is called felting, which is defined as “matting natural fibers together, or “squishing and agitating fibers until they form a heavy, dense ‘weave’”. Felting is possible due to the ridges and scales on natural fibers that create a texture to help them attach to one another during the felting process without any other attachment technique (similar to how velcro works).

Source: Business Insider

You can make felt out of essentially any animal's hair (including human hair!), but not all animal hair can compare to the legendary material that Stetson used for its hats. Sheep’s wool is rarely used in felting because it doesn’t lock together as tightly as rabbit fur, which is the modern alternative of the expensive fur that was commonly used back in the day by Stetson and other companies…beaver fur.

Source: How To Make Everything

So, what fur does Stetson use today? Hats are almost always made of a blend of different fibers, and today’s Stetson hats could be a blend of mink, chinchilla, cashmere, rabbit, and beaver fur. Beaver fur is the highest ranked natural fiber for hats, making it the premier fur for felting hats. It locks together tighter than any other natural fiber out there, and was the original fiber used when Stetson made his very first hat. 

The price went up a lot over time for beaver fur over time, so very little beaver fur is used in their hats today. Stetson has a rating system in order to give you an idea of how much beaver fur is in a hat: back in the day, “10X” was essentially pure beaver fur, “1X” was almost none, and everything in between was essentially describing a percentage of beaver fur used in the hat. Now, Stetson’s ranking system goes up to 500X, so the rating system is so diluted that you’ll never really know the exact ratio of beaver furs used in a given hat.

Why did hats go out of fashion after WWII?

  • Changes in the job market

  • Different ways of traveling

  • The decline of formal style

  • JFK’s fashion during his presidency

First, economic changes and industrialization changed the popularity of hat wearing because people were working indoors in factories more so than outdoors, where they might wear a hat to be protected from the elements.

Second, cars with roofs also created environments where people needed to be protected from the elements as much, making commutes outdoors shorter.

Third, general style became much more casual when soldiers came from WWII when Marlon Brando and James Dean popularized the t-shirt and jeans look.


Fourth, our main man JFK may have played a factor in this. Some say it’s myth, it’s legend, etc. but others swear by JFK really being the nail in the coffin for the hat market. Whether he refused to wear a hat or just wasn’t partial to one, we’ll never know. What we can say for sure is…he wasn’t much of a hat guy. Nowadays, it’s oddly considered to be a Politics 101 to never be seen wearing a hat as president. Why? We may never know for sure. 

The Takeaway

  • Oppenheimer probably wore a Stetson hat, but it’s impossible to be sure

  • Stetson and similar hats are felted from natural animal fibers

  • The popularity of hat wearing declined dramatically after WWII due to many developments across the US and other countries

The Iron Snail is a men’s fashion vlog starring a young man named Michael and featuring a snail no bigger than a quarter. The two are set on taking over the world of fashion by creating a clothing line to end all clothing lines. Until then, we’re here to tell you EVERYTHING you need to know about the best clothing out there, from the highest quality raw denim jeans to the warmest jacket to the sturdiest boots…the Iron Snail has got you covered.

Taylor Hale is your friendly neighborhood tea enthusiast, amateur knitter, skincare nerd, clothing thrifter, regular flosser, accidental teapot collector, vintage IKEA lamp hunter, overzealous plant owner, beeswax candle-lover, gal pal, and obviously, very serious academic. She writes for the Iron Snail, as you can see.


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