Best DIY washer and punch seed phrase kits

This page covers backups you mark yourself. Tile-in-a-rail products and capsules live on my metal seed backup rankings. Every grade below comes from Jameson Lopp's stress tests, graded as of 2025, and every price is what the maker's store listed on November 5, 2026.

Privacy. Lopp gives this as the first reason to build a washer backup: if commercial products are shipped to your house in your name, that information might be leaked in the future. In 2026 that happened again and again. Keystone says an attacker took 25,964 buyer records in October, SafePal says a plug-in exposed order data for 39,798 customers, Trezor's shipping provider exposed 80,689 customers, and Foundation's own domains were used to send phishing emails. Every one is on my security incident tracker. A bag of washers from a hardware store tells nobody you hold bitcoin.

Cost. Lopp's grades table prices the washer build at about $15 and the Steel Wallet DIY at about $20, less than any kit in my ranking.

The catch. Every strike is permanent, so a typo means starting over. Loose pieces such as washers or discs can come apart and land out of order, which is why every piece needs its word number on it.

Punchplate is the old Codl brand: codl.co now sends you to punchplate.com, and the Punchplate home page links Lopp's review as its independent test. Lopp tested the Codl Punchplate III, made from .071-inch 304 stainless steel, and found no problem reading it after the flame, the acid, or the press.

The store sells two layouts today. Standard records the first four letters of each word in a letter grid, so you never look up word numbers. Compact records each word's number from 1 to 2048 on a smaller plate. The layout Lopp tested punched four letters per word in a clockwise pattern, so neither current layout is exactly what he graded; the steel is the same grade.

Buy a kit: the 24-word Standard kit is $64.99 and the 24-word Compact kit is $44.99, each with two plates, one automatic center punch, a marker, and the word list. Two copies for two locations, one tool. Lopp's one con: it takes precision to punch and good eyesight to read, so mark every dot with the marker before you punch.

Lopp tested this design as the Hodlr Swiss: stainless disks with raised letters that you center-punch, locked inside a steel shell. It lost no data to heat or acid. The press could not visibly deform it, but it locked the device shut so tightly that he could no longer open it, which is why crush gets a B and the overall grade is an A-. The review page describes the lock-up as an intentional design decision, meant to keep the disks hidden after a collapse.

Hodlr now sells it as the Hodlr Shield 12 for €129, with stainless disks, a center punch, a marking pen, tamper seals, and a mat. Two caveats. The 24-word Shield uses titanium disks, which Lopp has not tested. Hodlr's cheaper Recovery titanium card at €89 is a different, untested product. Lopp also notes that punching on top of raised letters makes it harder to read the result at a glance.

Despite the name, you stamp this one: two 5 mm stainless plates with 24 numbered spaces plus four spare ones for a passphrase hint or notes, bolted together. It is on sale from €75, and a 4 mm (1/8-inch) A to Z and 0 to 9 stamp set adds €15. A hammer is not included.

Lopp found no data loss in any test. He also showed the problem with stamping: a few light strikes at the start, and letters rotated by the end because the stamp turned in his hand. Each plate weighs over a pound.

Steel Wallet DIY is a GitHub project with 3D-printable cases and holes for a numbered tamper seal around a 50 by 70 mm plate. Its author recommends grade 2 titanium or 316 stainless (1.4571, V4A) and guesses about €5 a unit if you already own the tools. The README says plainly that it carries no warranty.

Lopp tried stamping and Dremel etching on both titanium and steel plates, found etching worked better, and lost no data in any test. Pick it if you own a 3D printer or a rotary engraver and want a sealed plate with nothing bought from a seed-backup company.

Same 5 mm steel sandwich as the Coinplate Punch, with a letter grid you mark using the included automatic punch, on sale from €85. Lopp had no trouble punching it and lost no data. After the flame test, though, he could not unscrew the bolts with the supplied star wrench until later. If you buy it, store a stronger wrench with it.

Neither is in Lopp's table, so I hold both below every graded kit. Stamp Seed sells a Titanium Seed Stamping Kit from $136 for the Basic kit (for people who already own the tools) to $220 for the Deluxe kit with everything included.

Seedor's Safe Starter Set gives you one numbered steel disc per word, sealed in a capsule, for €125.21. Its own site says EU shipping outside Germany is paused and offers to help find a reseller, so most readers cannot order it direct right now.

Three more DIY designs earned top grades from Lopp, but I don't link their sites because the sites are gone or out of date.

Kits I would not buy, with no buy links.

This is the SAFU Ninja recipe as Lopp tested it. His parts list is an M6 or 1/4-inch stainless hex bolt 1 to 2 inches long, a matching stainless acorn cap nut, and 1/4-inch by 1-inch (or M6) stainless fender washers. Add a small letter and number stamp set (Coinplate sells a 4 mm, 1/8-inch set for its own plates), a hammer, and a steel block to hammer on.

If you want a jig to hold each washer, D-Central prints the open-source Blockmit DIY Washer Jig for $14.99 CAD in a 1-inch or a 24 mm metric size. Its page warns that an ordinary 16 to 17 mm M8 washer is too small for a BIP39 word.

Each device goes through three tests: a 2,000°F propane flame for 10 minutes followed by a plunge into water, 12 hours in 16% muriatic acid, and a 20-ton hydraulic press. If he cannot cause any data loss, the device gets an A; if it is easy to destroy, it gets an F. He says he won't test many more devices, because most new ones copy designs he has already graded.

The tests say nothing about how you made the marks. A light strike, a rotated letter, or a missing number can fail you before any fire does.

A metal backup is only as good as the seed the wallet generated. If you don't have a hardware wallet yet, pick that first.