Your seed phrase is the wallet. Everything else — the device, the app, the PIN — is replaceable. That's why the question isn't whether to back up your recovery words, but what you back them up onto. Paper is the default, and it's the wrong default for anything you plan to hold for years.
A metal backup stores your BIP-39 recovery words on steel or titanium instead of paper. You trade a pen for a punch, a stamp, or an engraving service, and you pay for durability. Here's how the main options differ, and where people get it wrong.
Why paper fails and metal doesn't
Paper ignites at roughly 230°C (450°F). A typical house fire reaches 600°C or more in a room, well past the point where a written seed phrase becomes ash. Water works more slowly: a flooded basement or a burst pipe turns ink into an unreadable smear over days, not minutes.
Steel doesn't melt until around 1,400°C, and titanium holds up past 1,600°C. That gap is the entire reason this product category exists. A stamped plate sitting in a fire-rated safe or buried in a garden can come out legible when paper wouldn't.
One catch. The plate survives; the ink or paint marking the letters might not. Look for options where the characters are physically stamped or punched into the metal rather than printed on top.
The main types of metal seed backups
Three broad designs dominate the market, and they fail in different ways.
Stamped letter plates
You punch each letter of each word into a steel plate using a hammer and letter stamps. The result is fully legible and doesn't depend on any numbering system. Downside: it's slow, loud, and a single mis-stamped letter can corrupt a word. Buy a spare plate to practice on first.
Tile-and-punch systems
These give you a grid of pre-stamped holes or a template, and you punch only the positions matching your words. Faster than freehand stamping and harder to mess up. Some use a numbering scheme where each word maps to a number, which means you also need to keep the wordlist or memorize the mapping. Lose that reference and the plate alone is useless.
Engraved and laser-marked plates
A shop or a service engraves your words onto stainless or titanium. Clean, compact, no hammering. The risk is custody: for a few minutes, a stranger has your seed phrase. Many people split the phrase across two plates so no single vendor ever sees the whole thing.
Comparing cost, effort, and risk
| Method | Effort | Main risk | Best for |
|---|---|---|---|
| Stamped letters | High | Mis-stamped characters | Patient DIYers |
| Tile-and-punch | Medium | Losing the numbering key | Most people |
| Engraved by service | Low | Vendor sees your words | Those who split the phrase |
Prices range from under twenty dollars for a basic steel washer kit to a few hundred for titanium. Don't pick based on price alone. Pick based on whether you'll actually finish the job.
A scenario that shows why this matters
Picture a two-plate setup. Plate A holds words 1 through 12, plate B holds 13 through 24. You keep A at home and give B to a parent in another city. A pipe bursts while you're traveling and floods the shelf where A sat. The stamped steel comes out fine after you dry it. Had that been an index card, you'd be locked out of a wallet holding, say, 0.4 BTC with no recourse.
Splitting has a cost too
Two locations mean two chances for one half to go missing. If you split, tell a trusted person the plan or store instructions with an estate document. Otherwise your heirs find half a phrase and no idea what it means.
What about Trezor specifically?
Trezor devices generate standard BIP-39 phrases, so any metal backup works. Trezor's own guidance leans toward metal for anything you plan to hold for years. The device and the backup are separate concerns; a metal plate doesn't replace your PIN or your passphrase.
Mistakes that defeat the purpose
- Storing the metal plate next to the device. A thief who finds both has everything.
- Photographing the finished plate "as a backup." Now your seed lives in cloud storage.
- Using a label maker or marker instead of stamping. Heat lifts adhesive and burns ink.
- Forgetting to verify. After you finish, wipe a test wallet and restore from the plate alone. If it doesn't work, better to find out now.
Frequently asked questions
Is a metal seed backup really necessary?
For small amounts you're actively trading, probably not. For savings you plan to hold for years, the case is strong. Metal costs more than paper but survives the two events most likely to destroy a paper backup: fire and flood. Think of it as insurance priced in tens of dollars against a total loss.
Can I make a metal backup myself?
Yes. Steel washers, letter punches, and a hammer will get you there for a modest cost. The main skill is patience and double-checking every character. Practice on scrap metal first, because a wrong letter means starting over.
Does a metal backup work with any wallet?
Yes, as long as your wallet uses standard BIP-39 recovery words. That covers Trezor and most major hardware wallets. The plate just stores words; the wallet software reads them the same way it reads a written list.
Should I split my phrase across two plates?
Splitting reduces the damage from a single theft or fire, but it adds complexity and a second point of failure. If you split, make sure whoever handles your estate knows both halves exist and where they live. Otherwise the protection becomes a puzzle nobody can solve.
Order a practice plate this week and stamp a throwaway phrase before you touch your real one.