DIY seed phrase storage remains a common choice for bitcoiners seeking affordability and privacy. Yet, security demands rigorous, tested standards.
Your seed phrase deserves nothing less than absolute protection.
This guide examines community-tested approaches using hardware store materials. It presents their construction, real-world stress test results, and critical limitations.
Why Go the DIY Way
Homemade seed phrase storage offers three distinct benefits without sacrificing core security.
It’s Affordable
Commercial solutions require a dedicated purchase. In contrast, DIY methods use budget-friendly off-the-shelf materials, often costing $10–$20 or less. This approach eliminates premium pricing.
It’s Easy to Build
You don’t need specialized equipment. Visit any hardware store for stainless steel plates, washers, or bolts. These materials are resilient against humidity, fire, and physical impact, meeting foundational security needs.
Plus, you likely already have the necessary tools at home, like a hammer for stamping letters.
It’s Private
Commercial products are shipped to your address, creating a paper trail that links you to Bitcoin ownership. DIY storage avoids this issue. By sourcing materials locally and paying with cash, your custody method remains private.
Basic Principles of Metal Seed Phrase Storage
Various methods exist for storing seed phrases, including paper and metal solutions. But one fundamental requirement remains across all custody models: the need for a durable and tamper-evident backup.
Material integrity guarantees your seed words remains secure for years to come. It includes resistance to fire and corrosion, and physical durability against impact damage.
A tamper-evident design reveals any unauthorized access attempts, allowing timely detection of potential security breaches.
These principles form the foundation of reliable DIY seed phrase storage.
How to Make a DIY Metal Seed Phrase Storage
While anyone can devise their own backup method, it’s essential to focus on community-tested and vetted approaches.
Two of them are presented below. They offer flexibility in design and materials, allowing you to create a customized solution that meets your specific needs.
By following these established approaches, you can create a robust and dependable metal seed phrase storage that protects your coins.
Hand-Stamped Metal Plate
The hand-stamped metal plate is a popular DIY approach for seed phrase storage. This method involves recording your seed words onto a metal plate.
The plate can be made from various materials, including 304, 316, 316L stainless steel, or titanium, offering a range of durability and corrosion resistance options.
While hand-stamping is a common approach, other techniques are available to record seed words onto the plate, like engraving and etching.
To create a secure storage solution, the plate can be combined with a tamper-evident mechanism, such as a bag, case, or pull-tight seals. This ensures that any attempt to access or modify the contents will be visible, providing an additional layer of security.
Tutorial
Here’s a simple tutorial with step-by-step instructions to get you started with creating your own hand-stamped metal plate:
Materials:
- 100x100x1.5mm 304 stainless steel plate (less than $5)
- Opaque, tamper-evident bag (less than $10 for a pack)
Important Note: If you have a passphrase, consider using a second metal plate, to store it separately from your seed phrase.
Tools:
- Hammer
- Letter punch set (less than $10)
- Stamping block (optional)
1. Position the Plate
Make sure the metal plate is clean. Then, place it on a flat and hard surface, ideally on a stamping block if you have one.
This will help prevent the plate from moving around while you stamp the letters, and also protect the surface below from potential damage caused by hammering.
2. Stamp the Seed Words
Using the letter punch set, begin stamping your seed words onto the metal plate. Follow these guidelines to ensure accuracy and legibility:
Stamp the number of the word in front of each word, to maintain the correct order, which is essential for recovery. Then, stamp each word individually, in the correct order.
To save space and time, you can stamp only the first 4 letters of each word. This is sufficient for recovery purposes, due to the properties of BIP39, BIP44, and SLIP39.
When stamping each letter, ensure the correct orientation of the stamp so that it can be easily read. Strike the stamp firmly 2 or 3 times to create a deep impression that will remain legible over time, even in the event of damage or degradation.
Double-check that each letter is clearly legible and accurately represents your seed phrase.
If you made a mistake while stamping, assess whether it affects the legibility of the word. If it doesn’t, try re-stamping the correct letter or word. However, if it significantly affects legibility, it’s best to start over with the word, either below or on the right side of the original attempt.
After striking each letter, return the stamp to its original position, making it easy to find and use again for the next letter. This will help you maintain a consistent and efficient stamping process.
3. Stamp the Passphrase (if applicable)
If you have a passphrase, position a second, different plate on a flat and hard surface.
Then, follow similar guidelines: Stamp it clearly and legibly, using the same letter punch set as before. Ensure that the stamping is deep enough to be easily readable, and that the passphrase is accurately represented.
4. Seal the Plate in a Tamper-Evident Bag
Once you’ve completed the stamping process, place the metal plate in an opaque, tamper-evident bag. Make sure the bag is properly sealed. This will ensure that any attempt to access the contents will be visible.
Note: If you have a passphrase, be sure to seal it in a separate tamper-evident bag to maintain the same level of security and separation as your seed phrase.
Other Noteworthy Examples
The hand-stamped metal plate approach has been tested and proven by various products. Both Bulletproof Bitcoin and SteelWallet have received A grades from Jameson Lopp’s stress tests, demonstrating their reliability and effectiveness.
SteelWallet
SteelWallet provides instructions for creating a secure steel plate solution.
The steel plate itself is resistant to heat, corrosion, and mechanical damage. It is housed in a 3D printed case that keeps its contents private, adding an extra layer of security. An integrated tamper-proof seal allows for the detection of any potential security risks.
With an estimated price of $5 (excluding tools), SteelWallet may be a highly affordable option.
Read the SteelWallet Test from Lopp.
Bulletproof Bitcoin
Bulletproof Bitcoin provides templates and instructions for ordering metal plates that can be secured together with bolts and nuts.
This solution also offers protection from heat, corrosion, and mechanical damage, as well as metal plate visibility protection through a dual-plate design. Tamper-evidence is achieved through the use of zip ties.
The estimated price range for Bulletproof Bitcoin is $50 to $90 (excluding tools), making it a more premium option.
Read Bulletproof Bitcoin Test from Lopp.
Washers and Bolt Seed Storage
This approach provides a cheap, compact and durable way to store a seed phrase. It involves recording your seed words on washers, thread them onto a bolt and secured them with a nut.
The solution can be customized with different metals, such as copper or stainless steel, varying sizes and lengths of bolts, and different shapes of nuts.
Hand-stamping is the most common approach for recording seed words. Using the 3D-printed Blockmit jig helps to align the stamps and ensure that the characters are evenly spaced and clearly legible.
To add an extra layer of security, the backup can be stored in a tamper-evident container or bag, making it difficult to access the contents without detection.
Tutorial
Here’s a simple tutorial with step-by-step instructions to get you started with creating your own washers and bolt seed storage:
Materials:
- M8 x 24mm 304 stainless steel washers (less than $5)
- M8 x 60mm stainless steel hex bolt (less than $1)
- M8 wing nut (less than $1)
- Tamper-evident bag (less than $10 for a pack)
Note: You’ll need 13 or 25 washers, depending on the length of your seed phrase (12 or 24 words). Add one extra washer to ensure that the first or last word is not visible.
Tools:
- Hammer
- Letter punch set (less than $10)
- Washer jig (less than $2)
- Electrical tape
- Stamping block (optional)
1. Prepare the Jig
The jig consists of 2 interconnected parts: a base and a mobile insert that slides into it. The base holds the washer in place, while the insert is designed to hold the letter stamp.
Unfortunately, there’s a risk the washer rotates when you move the insert between letters. If it does, you could overwrite existing letters or switch the order of the letters, which would render your stamped washer unusable.
To fix this, place some electrical tape at the bottom of the jig’s base. The tape will hold the washer securely, preventing it from rotating during the stamping process.
When you’re done, place the jig on a flat and hard surface, ideally on a stamping block if you have one.
2. Stamp the First Washer
Make sure the washer is clean. Then, place it in the base of the jig.
Place the insert at the first position of the first number (there are 2 positions for the numbers).
Pick the number stamp “0” and ensure it’s correctly oriented (so it can be read). Place it in the jig and strike it firmly 2 or 3 times.
Double-check that the number is clearly legible. If it isn’t, try re-stamping it, or start over with a new washer.
Then, remove the stamp, and return it to its original position (so it’s easy to find again).
Repeat this process for the second number position with the number stamp “1”.
Next, stamp the letters. While there are 8 positions for the letters in the jig, you can stamp only the first 4 letters of each word, to save time. This is sufficient for recovery purposes.
Move the insert to the first letter position, pick the letter stamp, and ensure it’s correctly oriented. Place it in the jig and strike it firmly 2 or 3 times.
Double-check that the letter is clearly legible and accurately represents your seed word.
If you made a mistake while stamping, assess whether it affects the legibility of the word. If it doesn’t, try re-stamping the correct letter. However, if it significantly affects legibility, it’s best to start over with a new washer.
Then, remove the stamp, and return it to its original position (so it’s easy to find again).
Finally, move the insert to the next position.
Repeat this process for the remaining 3 letter positions.
3. Stamp the Remaining Washers
Repeat the process for each remaining washer, using the corresponding numbers and letters from your seed phrase.
As you stamp each washer, pay attention to the correct orientation of the stamps and the positioning of the insert. If you make a mistake, assess whether it affects the legibility of the word and take corrective action as needed.
Continue this process until you’ve stamped all the washers, using a new washer for each word in your seed phrase.
4. Assemble the Backup
Stack all the washers on the bolt, in the correct order, from the last to the first. This will make it easier to recover the seed phrase in the future.
To add an extra layer of security, use the extra washer to hide the first word of the seed phrase.
Once all the washers are in place, screw the wing nut onto the bolt and tighten it firmly. Make sure it is tightened enough to hold the washers securely, but not so tight that it damages the bolt or the washers. This will secure the washers in place and prevent anyone from glimpsing at the words.
5. Make the Backup Tamper-Evident
To ensure the integrity of your backup, it’s essential to prevent anyone from accessing the contents without your knowledge. Place the assembled backup in a tamper-evident bag, and seal it according to the manufacturer’s instructions.
Other Noteworthy Example: SAFU Ninja
SAFU Ninja takes a similar approach, but with a few notable variations.
Instead of regular washers, it uses fender washers, which provide a larger surface area and more secure fit. This makes it easier to handle and stamp the washers, while also increasing security.
Additionally, SAFU Ninja uses a cap nut instead of a wing nut.
Despite these variations, it’s priced similarly, ranging from $5 to $10.
Read the SAFU Ninja Test from Lopp, and learn why it only got a B grade on the crush stress test.
When DIY Can Become Dangerous
While DIY approaches to seed phrase storage can be cost-effective and customizable, they can also be fraught with risks. Here are a few scenarios where this approach can go wrong:
- Insufficient material thickness: Using materials that are too thin or flimsy can lead to data loss due to wear and tear, corrosion, or other forms of degradation.
- Poor word alignment: If the words are not properly aligned or spaced, it can cause recovery failure, making it impossible to access the associated Bitcoin.
- Lack of tamper evidence: Without a clear indication of tampering, it may be impossible to detect if someone has accessed or modified the seed phrase.
- Lack of inheritance planning: If your family or heirs do not be immediately recognize your device as a seed phrase storage device, your coins may be lost forever.
However, it’s worth noting that all of these scenarios can be planned for and solved with proper consideration and execution.
For a more straightforward and reliable solution, consider Seed Keys. This purpose-built solution addresses common DIY pitfalls, using high-quality materials to prevent data loss, ensuring proper word alignment for easy recovery, and featuring tamper-evident design.
Plus, as a well-known brand, your heirs can easily find information about Seed Keys online, ensuring access to your coins when needed.
Conclusion
Secure seed phrase storage is a critical aspect of bitcoin ownership. While homemade approaches can be cost-effective, user-friendly, and private, they also come with risks and limitations.
The potential loss of your bitcoin would be catastrophic and irreversible.
Two of the most common DIY seed phrase storage solutions are stamped plates and stacked washers. Both methods involves recording seed words on a metal medium. And both have been tested and approved by the community.
When properly planned and executed, they can provide a reliable means of storing your seed phrase.
If you prefer a solution with less hassle and fewer risks, consider Seed Keys, a tamper-evident solution designed to keep your seed phrase legible and intact for decades.