Back Up Your Seed: Metal Plates, SLIP-39 & Shamir Secret

Back Up Your Seed: Metal Plates, SLIP-39 & Shamir backup

Table of contents

• Why backing up your seed phrase matters
• Backup options overview
• Metal backup plates — what, why and how
• SLIP-39 and Shamir backup explained
• Split seed phrase strategies and trade-offs
• Passphrase (25th word) and metal backups
• How to choose a backup strategy - quick decision matrix
• How to - step by step guides
• Common mistakes and security tips
• FAQ
• Conclusion and next steps

Why backing up your seed phrase matters

Your seed phrase is the root of your private keys and therefore access to your cryptocurrency holdings. If the hardware wallet fails, is lost, or the company ceases operations, the seed phrase is your recovery path. In my testing, the number of people who treated the seed phrase casually far exceeded those who took it seriously — and that often ended badly. So what should you do about it? Back it up in a way that survives time, fire, water and human error.

Backup options overview

Quick summary of common approaches

• Paper backup: cheap and easy, but vulnerable to fire, water and rot.
• Metal backup plates: physically durable, intended for long-term storage and resistance to environmental damage.
• SLIP-39 / Shamir backup: splits the seed into multiple shares with threshold recovery for redundancy and theft-resistance.
• Multisig setups: removes single-seed risk by requiring multiple signatures across devices or people (see multisig setups).

Each method has trade-offs in recovery complexity, security, and compatibility. I believe most long-term holders should combine two approaches rather than rely on one.

Metal backup plates — what, why and how

Metal backup plates are plates made of stainless steel, titanium or similar metals that let you record your seed phrase in a way that survives fire, water and time. There are a few ways to record words: stamping, engraving, laser etching, or punching. Stamping and punching leave deep impressions that survive severe heat. I tested stamped plates after submerging them and they were still legible.

Benefits

• High physical durability and longevity.
• Resistant to common household disasters.
• Single, compact backup that is straightforward to store or deposit.

Drawbacks

• If the plate and any separate passphrase are stored together, a single theft compromises everything.
• You still need to protect against theft and insider risk.

Image: [metal plate stamping - placeholder]

See a deeper comparison of metal options at /metal-backup-plates.

SLIP-39 and Shamir backup explained

SLIP-39 implements a Shamir Secret Sharing style backup for seed phrases. Instead of one 12- or 24-word seed phrase, you generate multiple shares and define a threshold. For example, a 3-of-5 scheme requires any 3 shares out of 5 to recover the recovery phrase.

How this helps

• Reduces single-point-of-failure risk: losing one share does not lose funds.
• Enables geographic distribution: keep shares in separate trusted locations.
• Can protect against coercion: no single share reveals the full seed.

Caveats

• Compatibility varies between wallets and recovery tools. Always confirm wallet compatibility before relying on SLIP-39 (see /wallet-compatibility-matrix and /shamir-slip39-guide).
• Share management is more complex than a single metal plate. Human error in storing and labeling shares is common.

In my experience, SLIP-39 is excellent for people who want redundancy and are comfortable with slightly more complex recovery procedures. But it is not a substitute for checking device compatibility and practicing recovery steps.

Split seed phrase strategies and trade-offs

People sometimes split a standard 24-word seed phrase across multiple locations by putting the first 12 words in one vault and the rest in another. This "split seed phrase" approach is simple but risky.

Why it can be risky

• If one half is stolen and the other half is discovered, an attacker reconstructs the full phrase.
• Partial phrases might enable targeted social engineering.

When it can make sense

• As a temporary measure while setting up a stronger backup.
• When combined with a passphrase stored separately (though that adds complexity).

Generally, I prefer SLIP-39 for deliberate splitting because it was designed for that purpose. Split halves of a BIP-39 seed are an ad hoc solution that creates fragile security unless handled carefully.

Passphrase (25th word) and metal backups

A passphrase — often called the 25th word — adds another secret to the seed phrase and effectively creates a distinct wallet. Many users ask if they should engrave or stamp the passphrase on the same metal plate as the seed.

My recommendation

• Do not store the passphrase on the same plate as the seed phrase. The combination defeats the point of the passphrase.
• Consider storing the passphrase separately from the plate in a different secure location (safe deposit box, trusted custodian of last resort, or offline memory if you can reliably recall it).

And yes, people forget passphrases when years pass. That has happened in real cases I know of. So choose a passphrase strategy you can maintain.

How to choose a backup strategy - quick decision matrix

Goal	Good options	What to watch for
Long-term, single-owner storage	Metal backup plate + remote duplicate	Avoid storing passphrase with the plate
Redundancy across locations	SLIP-39 (e.g., 3-of-5)	Verify wallet supports SLIP-39
Estate/inheritance planning	Metal plate + documented procedure + legal notes	Test recovery with a trusted executor (without exposing secrets)
Business or high-value custody	Multisig across devices/people	Operational complexity and legal agreements

How to - step by step guides

How to record a seed phrase on a metal plate

1. Prepare a clean, secure workspace free from cameras and phones.
2. Follow the seed phrase exactly from the device screen. Read aloud can reduce copying errors.
3. Stamp or engrave each word on the plate. Double-check spelling and order. Mistakes here are permanent.
4. If using multiple plates, number them and record only the plate number and location elsewhere (not the words).
5. Store plates in secure locations and consider redundancy (two plates in separate vaults).

How to create a SLIP-39 Shamir backup

1. Check that your hardware wallet supports SLIP-39 before initializing.
2. Choose the number of shares and the recovery threshold (e.g., 3-of-5).
3. Write each share on a separate metal plate or secure paper backup immediately.
4. Test the recovery process using a device you control (practice on a small test wallet first).
5. Distribute shares to trusted, geographically separate locations.

Need a walkthrough for device setup and recovery? See /seed-phrase-basics and /restore-recover-failure for related guides.

Common mistakes and security tips

• Buying plates or kits from sketchy sellers. Buy from reputable sources or make your own with clear, auditable stamping methods (see /where-to-buy-and-seller-safety).
• Photographing or typing your seed phrase into a phone or cloud note. Phones are compromised more often than people assume.
• Storing seed phrase and passphrase together. That removes the security benefit of the passphrase.
• Not testing recovery. Practice reconstructing from backups before you rely on them.

But also, don’t overcomplicate things to the point you never complete a backup. Simple, tested and practiced beats theoretically perfect but unused.

FAQ

Q: Can I recover my crypto if the hardware wallet breaks? A: Yes, if you have the seed phrase or SLIP-39 shares and know the passphrase (if used). Practice a recovery with a spare device or recovery tool first. See /restore-recover-failure.

Q: What if the company that made the hardware wallet shuts down? A: A properly backed up seed phrase or SLIP-39 shares lets you recover funds with compatible recovery tools or other wallets, provided the standards are followed.

Q: Is SLIP-39 safe if I lose one share? A: If your threshold is set appropriately (for example 3-of-5), losing one share does not prevent recovery. But losing enough shares to drop below the threshold will prevent recovery.

Q: Should I engrave my passphrase on metal too? A: Not on the same plate as the seed. Consider storing the passphrase separately in a different secure location.

Conclusion and next steps

Backups are not optional. Metal backup plates offer durability; SLIP-39 provides redundancy and flexible recovery thresholds. Each approach costs time to set up and test, but that effort pays off if hardware fails or time erodes memory. In my experience, the safest outcomes come from combining a durable physical backup and, for higher-value holdings, a tested SLIP-39 or multisig plan.

Ready to protect your seed? Read our practical guides to get started: /seed-phrase-basics, /shamir-slip39-guide and /backup-recovery-best-practices. Practice a recovery now so you know it works when you need it.