ESSAY — Technology & Design

The Design Philosophy of Equipment Selection

We tested every alternative under diverse climate conditions at home and abroad
and present only what survived.

Key takeaway: There is no single right answer. But every item that survived testing across all alternatives has a reason for being here. By documenting this trial-and-error process, we save the next person's time.

1. A Design That Fits in a Household

TokiStorage keepsakes are made with household equipment, not industrial machinery. Print a QR code and protect it with UV lamination. Soap follows the same principle: melt an MP soap base, pour into a mold, attach a label. No specialized equipment appears in any step.

Reaching this conclusion required renting three self-storage units in Ichikawa, Urayasu, and Shin-Urayasu. Each facility stored candidate equipment and supplies for hands-on comparison. We went through four laminators, three printers, and five types of film. For soap, we tested different soap base brands, oil varieties, mold shapes, and colorant types exhaustively.

Testing didn't stop in Japan. We brought the same equipment set to Maui and manufactured there as well. Different voltage, different humidity — could the same procedures produce the same quality? The household equipment's versatility held up. The laminator runs on 100–240V, the printer connects via Wi-Fi Direct, the software runs in a browser. Location independence is a deliberate design choice, not a coincidence.

This effort makes sense precisely because these are keepsakes, not mass-produced goods. Mass production starts with equipment ROI calculations. Keepsakes are unique, with unpredictable volumes. Minimizing upfront investment and completing everything with household equipment is the starting point of a design philosophy that says "anyone, anywhere, can begin."

2. How This Differs from Traditional Keepsakes and Gifts

In the traditional keepsake and gift economy, outsourcing to a specialist is the norm. Wedding favors, corporate novelties, event souvenirs — all selected from catalogs, ordered in minimum lots of hundreds, at unit prices ranging from several hundred to several thousand yen. The concept of equipment selection doesn't exist. You choose a vendor and a product, not a method of production.

This structure has two constraints. First, minimum order quantities are high. If you make 100 but only give away 30, the materials for the other 70 are wasted. Second, making just one is impossible. The operation of "making exactly one, today, for this one person" simply doesn't exist.

Designing for household equipment to produce one piece at a time removes these constraints entirely. Material cost is about 30 yen per piece. Inventory risk is zero. Make what you need, when you need it. The reason equipment selection matters so much is that the equipment itself is the foundation supporting this "start from one" structure.

Wedding favors are a perfect example. Ordering from a vendor requires minimum lots matched to guest count, inevitably producing leftovers. Handmade favors let you create one piece at a time, tailored to each guest. Add a voice QR with a recorded message, and it becomes a keepsake no off-the-shelf product can match. All at a material cost of 30 yen per piece.

Production capacity is realistic too. From experience producing 250 soap keepsakes solo for a neighborhood association event, the entire run took about 8 hours. A typical wedding has around 80 guests. The couple could spend a day at home crafting them, or a dedicated space could be set up at the venue where the finishing touches happen in front of guests. The portability of household equipment makes either option possible.

3. TokiQR DIY Equipment

Manufacturing voice QR keepsakes requires just five things: a PC, a printer, a laminator, UV lamination film, and copy paper. Below, the rationale for each selection and the alternatives we tested and rejected.

PC — MacBook Air

TokiQR's encoding interface runs in the browser. Codec2 WASM compresses voice and generates QR codes within Chrome. Technically, Windows PCs and Chromebooks work too. However, macOS offers superior color reproduction consistency and font rendering. Since voice QR keepsakes are visual products, the proximity between on-screen colors and printed results matters for quality control.

Considering portability, the MacBook Air's battery life and weight make it suitable for on-site work anywhere. Amazon →

Mobile Printer — Canon TR163

An A4 color inkjet printer. The most critical criterion: it must not be thermal. Thermal printers fade under UV light. Using thermal printing on a keepsake protected by UV lamination means UV rays penetrate through the film, and text disappears within years. Inkjet pigment and dye inks avoid this problem entirely.

A desktop inkjet multifunction printer works functionally. But for the use case of printing on-site, a mobile printer is more practical. We considered A3 models, but the larger body sacrifices portability. Staying with A4 keeps everything bag-sized. The Canon TR163 supports A4 full-color, Wi-Fi Direct, and has a built-in battery. Amazon →

A4 Laminator — bonsaii

Temperature control made the biggest difference in laminator selection. We tested two budget models (around 3,000 yen each), and both suffered from temperature unevenness that caused film edges to peel. For a keepsake, peeling is unacceptable. We also tried laminators with built-in cutters, but cutting quality was inconsistent. Not everyone can produce the same result, so we removed the cutting step from the process entirely.

Like printers, A3 laminators exist but the larger body makes them impractical to carry. Staying with A4 preserves portability. The bonsaii laminator offers adjustable temperature, warms up in about one minute, and works well with 100-micron film, achieving uniform adhesion right to the edges. Under 10,000 yen for this quality. Sufficient. Amazon →

UV Lamination Film — Aska A4, 100 Sheets

Film thickness defines the options. We tested 75, 100, and 150 microns. The 75-micron film is cheap but tends to curl after lamination. The 150-micron is too thick, affecting QR code scan accuracy due to increased light refraction. 100 microns hit the optimal balance between curl resistance and optical transparency.

UV protection directly prevents print fading. Taking keepsakes to Maui, where sunlight is intense, made the necessity of UV protection viscerally clear. Even in a six-month window-sill exposure test back home, standard film showed a clear color difference versus UV film. Given that keepsakes may be displayed in sunlit locations, UV protection is essential. Amazon →

Copy Paper — Kokuyo A4, 500 Sheets

We compared glossy, matte, and plain paper. Intuitively, glossy paper seemed more "keepsake-worthy." However, after lamination, the outer film determines the gloss, making the paper's own finish nearly irrelevant to the result.

Matte paper absorbs ink well but costs three to five times more than plain paper. With virtually no visible difference after lamination, plain paper wins on cost efficiency. Kokuyo's high-whiteness type maintains consistent brightness with minimal variation between lots. Amazon →

Document Scanner — PFU ScanSnap iX2500

QR PDFs generated in Bulk Mode can be printed and stored as paper. As long as the paper survives, scanning it back to PDF and decoding the QR codes with software restores the voice. No camera required. QR error correction absorbs the noise introduced by printing and scanning, so the digital data suffers zero degradation. Digital and analog become mutual backups — a bidirectional restoration path.

For partner venues handling large volumes of QR PDFs, a document scanner with an ADF (automatic document feeder) is efficient. Load a stack of paper and digitize it all at once. The ScanSnap iX2500 reads 45 pages per minute (duplex), supports Wi-Fi, and outputs directly to PDF via its touchscreen. Amazon →

For smaller quantities, a household flatbed scanner or smartphone camera works just fine. Choose based on scale.

4. Pearl Soap Materials

Pearl Soap is a gift for those we've had the good fortune to connect with. Soap is a "usable keepsake" — not just for display but for actual use.

Another advantage of soap making is that anyone can participate regardless of age. We made soap together with our five-year-old daughter. Choosing colors, pouring into molds, waiting for it to set — she helped eagerly, and the time itself became a family memory. The process of making a keepsake becoming an experience in itself is a value that outsourcing to a vendor can never provide.

Below, the selection record for each material.

MP Soap Base

Handmade soap follows one of two methods. CP (Cold Process) uses sodium hydroxide (lye) and oils in a full chemical reaction, offering high flexibility but requiring careful handling of caustic materials. MP (Melt and Pour) melts a glycerin-based soap by heating it, then pours it into molds. That's it.

Considering that keepsakes may be produced on-site, bringing sodium hydroxide to the location is not an option. MP is the only choice. The MP soap base offers high transparency and works well with colorants. Amazon →

Coconut Oil

Coconut oil's role is scenting. Essential oils are the typical choice for adding fragrance to soap, but scent preferences vary sharply. Lavender, rose, mint — each has its fans and its detractors. Fragrances that are universally inoffensive and genuinely liked are rarer than you'd expect.

After extensive testing, two survived: plumeria and coconut. Both evoke Hawaii. Plumeria is elegant but often met with "what scent is this?" Coconut is different. Everyone recognizes it instantly, recalls tropical air, and feels their mood lift. As a gift, the moment someone picks it up, coconut delivers an immediate, no-explanation-needed positive impression. Amazon →

Food-Grade Colorant — 8-Color Set

Soap colorants come in many forms: soap-specific pigments (such as mica), glow-in-the-dark colorants, powder colorants, and food-grade liquid colorants. Soap-specific pigments offer vivid colors, but their skin safety is evaluated under the assumption of "rinsing off as soap." Glow-in-the-dark colorants look fun but lack sufficient safety data. Powder colorants tend to produce color unevenness and can stain hands and sinks when used.

As a gift, soap may end up in households with infants. A wider safety margin is always better. Food-grade liquid colorants meet oral-ingestion safety standards and, being liquid, blend uniformly into the soap base. An 8-color set covers the major colors out of the box. Mixing can produce additional shades, but it tends to cause color unevenness and makes reproducing the same color difficult. Using single colors is preferable. Amazon →

Paw Mold

Silicone molds come in endless shapes: hearts, flowers, shells, animals. The criterion wasn't photogenic appeal but rather: "Can someone in both Japan and Hawaii receive this and feel genuinely happy, without any misunderstanding?"

Hearts are classic but can feel "heavy" as a gift for some. Flower shapes carry different meanings across cultures. Shells divide opinion. The paw shape was chosen because of the story behind it — our beloved dog Pearl is the origin of the Pearl Soap brand name. That story lives in the shape itself.

On the practical side, the rounded paw form resists chipping and sits neatly inside a pouch. Regardless of age, gender, or whether someone is a dog person, the response is "that's cute." In both Japan and Hawaii, it's one of the few shapes that carries no cultural misinterpretation. Amazon →

Mini Frying Pan (Square)

MP soap can be melted by microwave or direct heat. Microwaving is convenient but draws significant electricity, cannot be used outdoors, and is impractical for disaster-preparedness scenarios. It also produces temperature unevenness — overheating causes the soap to boil, introducing numerous air bubbles. Placing the soap base directly in a mini frying pan over low heat allows controlled, even melting without relying on a power grid.

The shape matters: square, not round. When pouring melted soap into molds, a round pan has no spout and spills easily. A square frying pan's corners serve as natural pour spouts, enabling precise pouring into small molds. Amazon →

Cassette Stove — Iwatani Slim

Heat sources include IH cooktops, gas stoves, and portable cassette stoves. IH cooktops often fail to heat the mini frying pan due to its small base. Kitchen gas stoves work but fix the workspace to the kitchen.

A cassette stove enables heating right on the work table. Melting soap base requires only the lowest flame, making it inherently safe. The Iwatani Slim is thin, stable, and offers fine heat adjustment. It's portable enough to bring anywhere, and doubles as a disaster-preparedness tool. Not a specialized piece of equipment — just an everyday item that happens to do the job perfectly. Amazon →

Overseas, cassette gas cartridge standards may differ. In Hawaii, propane gas burners are readily available locally and work as a substitute. When open flame is restricted at indoor facilities, IH cooktops or heat sheets are viable alternatives. The soap base melts at around 70°C, so any heating method or device that exceeds that temperature will work. In that case, a container compatible with the chosen heating method is also needed.

Mixing Cups and Sticks

Mixing colorant and oil into melted soap requires heat-resistant cups and sticks. Heat-resistant cups are available at 100-yen shops too, so substitution is possible.

As long as you're making the same color, a cup can be reused several times. However, soap builds up in layers on the cup wall each time it melts and solidifies. As layers accumulate, cleaning becomes increasingly difficult and the risk of color contamination rises. Having enough cups to swap in a fresh one when changing colors is the practical approach. Amazon →

Organza Pouch

We tested leaves, paper, non-woven bags, direct OPP bag wrapping, and even bare hand-off with no packaging. Soap has a property of slightly melting at certain temperatures. Paper and non-woven fabric absorb the melted soap. OPP bags cause the surface to stick. Leaves look beautiful but lack durability. Bare hand-off fails on hygiene.

Organza pouches were the only option unaffected by slight melting. The mesh fabric doesn't absorb soap, and it dries back to normal. Better yet, organza's mesh works as a lather net — wet the pouch with the soap still inside and it foams up. Functional beyond appearance. The semi-transparency also lets the soap's color and shape show through, a clear advantage for gifts where "seeing the contents without opening" matters. Amazon →

OPP Bags

Initially, we tried going without individual wrapping. Then someone carried the soap in just an organza pouch, kept it in their pocket for half a day, and body heat melted it — the pocket was a mess. That feedback settled the decision to individually wrap each piece.

We considered zip bags, but their sealing capability is overkill for soap. OPP bags (clear film bags) open easily, offer high transparency, and cost less than half of zip bags. The slight fragrance permeation is actually an advantage for gifts. Amazon →

Label Printer — P-touch Cube PT-P710BT

Applying brand labels to soap and pouches requires a label printer. We compared two brands: Tepra (King Jim) and P-touch (Brother). Tepra has higher domestic market share, but the P-touch smartphone app offers a more intuitive UI. Print quality is comparable, but tape compatibility and pricing give P-touch a slight edge.

What sealed the recommendation for P-touch was global availability — especially tape cartridges. Seeing a wide selection of P-touch tapes on the shelves at OfficeMax in Maui settled the decision. Tepra tape is hard to find outside Japan.

Another deciding factor for P-touch: it can print QR codes as images on tape. Paste a QR code image in the smartphone app and output it directly onto tape. We tested 12mm and 24mm widths. At 12mm, the QR code's cell count makes the size too small, raising scan reliability concerns. At 24mm, a QR code plus multiple lines of text fit comfortably, letting a single label carry all the information needed.

The PT-P710BT connects via Bluetooth, supports 24mm-wide tape, and prints directly from a smartphone. Its portability supports on-site work anywhere. Amazon →

The tape cartridge is TZe-155 (24mm), white text on clear background. The transparent base lets the soap's color show through regardless of the shade. Amazon →

5. Designing the Initial Investment

An approximate breakdown if purchasing all equipment new:

With an existing PC and printer, the additional investment is roughly 30,000 yen. Per-unit material cost runs about 30 yen per voice QR sheet (5 yen paper + 25 yen film) and about 30 yen per soap. Each keepsake costs roughly 30 yen to produce. Orders of magnitude below industrial equipment investment.

30,000 yen upfront. 30 yen per piece.
These numbers are the proof that anyone can start.

Alongside equipment selection, we tested major fabrication and engraving technologies: laser engraving, UV printing, etching, 3D printing, and more. The details are beyond the scope of this essay, but the process of elimination led us to laser QR engraving on quartz glass as a permanence technology. Paper and film degrade over decades, but a QR code engraved in quartz glass persists as long as the glass itself remains intact.

We also tested numerous engraved keepsakes: wooden keychains, cork coasters, metal cards, mirrors — each sourced as raw material and engraved with custom messages and designs using a laser engraver. The results were beautiful, but engraving machines are expensive, and bringing one into a home or a venue is prohibitively difficult. Since it conflicts with the "anyone can start" design philosophy, laser engraving for keepsake production was ruled out.

We also tested diverse procurement channels: Amazon, Temu, AliExpress, and local sourcing. Temu is cheap and convenient, but we experienced packaging tearing open and paint leaking onto other items in the same shipment, rendering them unusable. Overseas shipping varies by region in carrier and delivery time, making stable production schedules difficult to maintain. AliExpress alternatives often didn't match domestic product dimensions, and sourcing replacement parts when something went wrong proved challenging. For reproducibility and reliability, Amazon is the superior choice. Being able to repeatedly procure the same product at the same quality matters most in keepsake production.

6. Conclusion

There is no single right answer. Whether the equipment listed here is optimal depends on each person's environment and goals. However, every item that survived testing against all alternatives has its own reason for remaining.

The intent of publishing this record is simple: so that the next person walking this path doesn't repeat the same trial and error. If the experimentation we've accumulated at home and abroad saves someone a single day, that's enough.

Document the trial and error.
That becomes the most practical gift to the next person who begins.