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  • Writer's pictureeconoalchemist

Don't fear it, secure it.

An article on securing and recovering a Bitcoin seed phrase with the Hodlr Disks stainless steel backup. If you value permissionless money and the ability to transact without being censored then self-custody and get your bitcoin out of third party control.

This article covers unboxing, testing, and reviewing the Hodlr Disks made by Hodlr Swiss. I am not paid by, endorsed, or sponsored by Hodlr Swiss. My intensions with this article are to share my thoughts about this backup device. I hope that by the end you see that self-custody is not scary and learn how to secure your Bitcoin backup in a secure medium like stainless steel. Around the end of November, Hodlr Swiss reached out to me to see if I would be interested in unboxing, testing, & reviewing their new stainless steel backup, the Hodlr Disks. Since I have a propensity to focus on self-custody & secure backups, I thought that this would fall neatly into my wheelhouse. After looking at the product on the Hodlr Swiss website, I agreed to give this a shot. It looked really clean and cool, well made, and I wanted to try it out for myself. I'm glad that I did because I was really impressed with it, and I hope this article gets you thinking about incorporating a secure metal backup into your Bitcoin operating procedures.


The Hodlr Disks are packaged in a heavy-duty, sealed, non-transparent plastic bag. I liked this because any tampering that may have occurred en route would be made evident by un-repairable damage to the bag. Not that tampering would be as detrimental to a stainless steel backup device as it would be to a hardware wallet, but it's just nice to know that I received the product exactly as the manufacturer had sealed it.

Upon opening the packaging, you will find a box which contains the following items:

  • 1 x Marker

  • 2 x Camera covers

  • 1 x Set of ear plugs

  • 5 x tamper evident seals

  • 1 x Pencil

  • 1 x Hodlr Disk

  • 1 x Hex wrench

  • 1 x Automatic punch

  • 1 x Instruction manual

Hodlr Swiss really thought of everything when packaging this product, literally everything a person needs to transfer a Bitcoin seed phrase to the Hodlr Disks is included.


In this example, I'm demonstrating a scenario you may find yourself in. If you have taken the first steps in self-custody then you probably have your wallet's seed phrase (typically 12 or 24 words) written down on paper. Congratulations on taking the first step in securing your sovereignty. But you may have thought about or even lost sleep over the idea of your Bitcoin seed phrase going up in a blaze of fire or being damaged by flood or other environmental hazards. This is where secure metal backups come in handy, products like the Hodlr Disks offer a robust, stainless steel backup for your seed phrase that will survive extreme environmental conditions. There are a wide variety of products and DIY methods for creating a secure metal backup, such as my previous article explains here.

Next, I will demonstrate how to transfer a seed phrase written on paper to the stainless steel Hodlr Disks.

Transfer your existing seed phrase to the provided and appropriate slip of paper that came with the Hodlr Disks. There are a few different formats available such as a 2 of 3 scheme, Shamir 3 of 5 scheme, and a twins scheme. In this example, I am demonstrating the solo 1 of 1 scheme.

A common theme among all the schemes is that only the first 4 letters of each word are required in order to secure your backup. This is because the industry standard BIP39 Word List is comprised of 2,048 words, none of which share the same first 4 letter sequence. So by securing the first 4 letters of any word on that list, you know that there can be no mistaking it for a different word. Each of the selected 24 index numbers on the scale from 0 - 2,047 are calculated from 24 groups of 11 binary bits that make up your private key, but that is a topic beyond the scope of this article.

In this video, I demonstrate how to transfer an existing 24 word Bitcoin seed phrase from a notebook to the provided slip of paper. This helps to ensure that my focus is only on the first 4 letters of each word in the next step. If you have a phone or other camera-equipped device near by, you can use the provided camera covers to ensure that no prying eyes see your seed phrase. Make sure you don't read your seed phrase out loud either, as some devices may be recording you.

Now that the 24 seed words have been transferred to the slip of paper, the next step is to use the marker to indicate each letter on each ring of each disk that needs to be stamped. Each Hodlr Disk has 24 disks inside of it. Each of these disks has 4 rings impressed on it. Each ring contains the entire alphabet. This way, the outer most ring will be used for the first letter, the second ring for the second letter, the third ring for the third letter, and the fourth ring for the fourth letter. Each disk is also marked with a number 1-24 and also has small circles on it that correspond to the disk number. This is helpful for cases of restoration after exposure to extreme environments where either the numeric value or the circles are damaged.

In the next video, I demonstrate how to use the marker to indicate which letter in each ring that needs to be stamped. Using the marker first, allows you to double check your work before proceeding with the irreversible spring-loaded punch. After marking your letters with the marker, make sure to double check your work. If you made a mistake you can easily clean the marker off with some alcohol.

Once all the letters have been marked on all the disks and the work has been double checked, it is time to stamp the letters with the included spring-loaded punch. Simply put the pointy end of the punch on the desired letter and apply pressure until the spring releases and punches the disk with an indentation on the intended letter.

After the first 4 letters of each seed word have been stamped into the disks, it's a good idea to indicate the Share-Of-Threshold. This makes it easy to keep track of which piece in a set the disks are, how many pieces belong to that set, and the minimum threshold required from that set to restore your wallet. For this demo, it was just 1-1-1 because this is the first share of one piece with a minimum threshold of one piece necessary to restore.

Also, there are some grids on the back of the Hodlr Disks where the user can punch a unique identifier for the disks. This one was named "DEMO".

Once the Hodlr Disks are all stamped and good to go, it is a good idea to verify that your wallet can be restored based on the information available in the backup. Try to use only your backup to recreate your seed words. Then use those seed words to try and restore your wallet on your hardware or software wallet. If everything checks out, then it is probably safe to burn the paper copies of your seed phrase.

The Hodlr Disks come with tamper evident stickers that are to be placed over the locking set-screw once everything is finished. There is a unique identifier on each sticker; so it is a good idea to notate that number and keep track of it so you can be sure that no one has accessed the backup and placed another replica sticker back in its place.

Stress Testing:

Once the tamper evident sticker is applied, the Hodlr Disks is ready for storage. But what happens if the place it's being stored catches on fire? I wanted to find out and Hodlr Swiss wanted to find out too, so in this next video I demonstrate bringing the Hodlr Disk up to white-hot melting temperatures and then evaluate the ability to restore the seed entirely afterwards. This video has been time-lapsed but the actual elapsed time was 15 minutes. Stainless steel has a melting point of roughly 2,500 °F, which is the point I brought it to.

How it started: How it's going:

After heating up metal moving parts like that, it is normal for them to be difficult to take apart. The threaded cap was not able to be removed by hand after this heat stress test. I tried using a punch & hammer and the set-screw hole as a spanner point, but the distortion from nearly melting was too bad and the pieces would not spin apart. I ended up using a cutting disc on a grinder to split the outer ring into two pieces.

Once the outer ring was removed, the 24 disks inside were seemingly fused together. I took a small chisel and had to individually pry the disks apart. After the 12th disk either the pressure was so great on the rivet or the wear & tear got to it and the rivet broke. This was a good thing because it made getting the remaining disks apart easier.

Once all the disks were taken apart I found that every single stamped letter on every single disk was still identifiable. In other words, I could restore my wallet.

Even under extreme environmental conditions, the Hodlr Disks did their job. The seed words were recoverable. These are a less labor-intensive alternative to some of the other metal backup options. If you do choose to use the Hodlr Disks, you can use multiple units to create different types recovery schemes. There is also a heavy duty magnet in the back plate so that the disks can be stacked together or stuck to a metal surface.

Thanks for reading! I hope you enjoyed this article and it got you thinking about the different kinds of secure backup options out there, the Hodlr Disks definitely do the trick. Securing your Bitcoin backup and taking the necessary steps to self-custody is easy. Products like the Hodlr Disks take some of the work out of it for you and make it even easier. Considering the recent FinCEN Travel Rule changes, the best time to start taking self-custody seriously is right now. If you value permissionless money and the ability to transact without being censored then self-custody your bitcoin and get it out of third party control. Make sure your backup is as secure as possible with a metal backup like the Hodlr Disks.

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