This article describes common shop practice for custom acrylic (PMMA) boxes. Sheet grade, adhesive, and equipment change the result. Figures below are typical production ranges, not certified material limits.
Short answer
A custom acrylic box is usually made from flat PMMA sheet that is cut to a panel set, edge-finished, then joined with solvent cement or a clear adhesive. Locks, slots, and print are added after the body holds its shape. Cast sheet is the usual choice when edges must stay clear; extruded sheet is more often used when cost and bend consistency matter more than optical edge quality.
That sequence is the same for a ballot box, a donation box, a suggestion box, or a small collection box. What changes is sheet thickness, the slot, the lock, and whether one panel is meant to be removed.
What a custom order actually specifies
In fabrication, “custom” means the factory is not pulling a fixed mold. The controlled inputs are usually:
- Outside size, in millimeters, with a stated tolerance
- Sheet type and nominal thickness
- Color: clear, tinted, opaque, or a mix of panels
- Opening type: top slot, side slot, or a removable lid
- Hardware: lock, hinge, feet, or a wall bracket
- Graphics: UV print, screen print, or a separate insert
A workable drawing lists inside and outside dimensions, which face is the front, and where the slot sits relative to the top edge. Without that, two shops can both call the box “300 mm wide” and still build different internal volumes.
Cast sheet versus extruded sheet
Commercial acrylic sheet is polymethyl methacrylate, supplied mainly as cell-cast or continuously extruded sheet. ASTM D4802 is the common U.S. specification covering acrylic plastic sheet; it classifies sheet by type and does not, by itself, tell a buyer which box design to choose.
| Point of comparison | Cell-cast sheet | Extruded sheet |
|---|---|---|
| How it is made | Polymerized between plates or in a cell | Melted and pushed through a die |
| Typical box use | Clear display faces, polished edges, thicker panels | Simple bent lids, cost-sensitive runs, thinner covers |
| Edge after polishing | Usually clearer, with less visible extrusion line | Can show more stress or a duller edge if overworked |
| Thickness choice | Easier to source above about 6 mm | Common in thinner gauges, often 2–5 mm |
| Main tradeoff | Higher material cost, better optical edge | Lower cost, more sensitive to heat and solvent stress |
Neither type is universally stronger. Impact behavior depends on thickness, notch shape, temperature, and how the joint is made. A polished 5 mm cast panel and a 3 mm extruded lid are not comparable parts.
Manufacturing sequence
1. Confirm the panel list
The shop nests front, back, sides, base, and lid on a sheet. A five-sided collection box often uses a separate lid rather than a formed hood. Internal clearance for a lock cam should be checked before cutting; 8–12 mm is a common planning gap, not a fixed rule.
2. Cut the sheet
Panel saws, CNC routers, and CO2 lasers are all used. Saws and routers leave a matte edge that can be scraped and polished. Lasers leave a glossy edge on many clear sheets, but the edge can craze later if the sheet is stressed or if the wrong cement is used. Laser cutting is a poor default for very thick cast sheet.
3. Finish the edges
Visible edges are scraped, sanded, then buffed. Hidden glue edges are left flat so the joint has contact area. A flame-polished edge looks bright, but it can lock in stress. For a lockable box that will be shipped, mechanical polishing is the more predictable finish.
4. Add slots, holes, and print
The drop slot is cut before assembly when the panel is still flat. A typical paper slot is about 4–8 mm wide and long enough for the form, with the ends radiused so the sheet does not crack from a sharp internal corner. Coin slots are narrower. Logos are usually UV-printed on the inside face of a clear panel so the ink is not rubbed off.
5. Bond the body
Solvent cement softens the mating edges so they weld as the solvent leaves. Capillary cement is used on tight seams; a thicker cement is used if the gap is uneven. UV-curing adhesive is an alternative when the joint must stay clear and the parts can be fixtured. Screws alone are a weak way to close a clear box, because the hole is a stress point.
6. Fit hardware and inspect
Locks, hinges, and feet go on after the body has cured enough to handle. Inspection usually covers size, joint clarity, slot position, lock function, and surface scratches. For export, panels are filmed or boxed with corner protection; acrylic scratches more easily than the public face suggests.
Thickness, slots, and hardware
These are order-planning ranges used for small collection boxes, not performance ratings. A taller floor box often needs a thicker base and a frame, even if the front panel stays clear.
| Use | Common nominal thickness | Opening | Hardware note |
|---|---|---|---|
| Countertop suggestion box | 3–5 mm body, 3 mm lid | Top slot, often 5–8 mm wide | Small cam lock is enough if the lid is the only access |
| Donation or tip box | 4–6 mm, thicker base if coins are heavy | Narrow top slot | Lock on a side or rear door, not through the display face |
| Ballot or entry box | 5–8 mm for a tabletop body | Wide slot for folded paper | Lock plus a defined door; slot should not align with the latch |
| Floor-standing box | 8–10 mm panels, or thinner panels on a frame | Slot on the upper third | Base weight or a wall tether matters more than panel thickness alone |
A practical size tolerance for a bonded box is often ±1 mm on panels under 400 mm, widening as the part grows. Ask the shop to state the tolerance on the outside size, not only on the cut panel.
Bonding and edge finish
| Method | Best fit | Limit |
|---|---|---|
| Capillary solvent cement | Tight, square seams on cast sheet | Poor gap filling; fumes need ventilation |
| Viscous solvent cement | Slightly uneven edges, small fillets | Can leave a visible bead if over-applied |
| UV adhesive | Clear joints where solvent blush is unacceptable | Needs UV access and clean surfaces |
| Mechanical polish | Visible edges on display boxes | Adds labor; does not hide a bad joint |
| Flame polish | Fast gloss on simple edges | Can add stress; avoid on cemented areas |
Which build fits which use
For a retail counter, a 4–5 mm clear body with an inside-printed logo and a rear lock is usually enough. The slot should sit behind the front face so cards do not spring back out.
For a charity event, tinted side panels and a clear front keep the contents visible without showing every fingerprint. A removable locked door is more useful than a glued lid if staff must empty the box daily.
For a school or office suggestion box, opaque or frosted sides reduce the urge to read notes through the wall. Wall mounting needs a separate bracket; do not rely on double-sided tape for a locked box.
For a voting or raffle box, specify the paper size, the slot length, and who holds the key. Thickness alone does not make the box secure. The latch, the door gap, and whether the slot can reach the lock matter more.
Factory context, separate from the process
The steps above are general acrylic fabrication. They are not unique to one brand. SKBallotBox.com is a product site operated by Sunday Knight Co., Ltd., a Dongguan factory that has made custom acrylic ballot, donation, and suggestion boxes since 2012. Public company pages describe factory-direct OEM and ODM work, a usual minimum of about 100 pieces per design, and shipments to buyers in more than 50 countries. Those commercial terms do not change the physics of cutting or cementing sheet.
Category examples on that site include acrylic ballot boxes, donation and collection boxes, and suggestion boxes. The about page states the factory location and product scope. Use those pages for ordering details; use the process sections above to judge a drawing.
FAQ
Is acrylic the same as plexiglass?
In trade use, both names usually mean PMMA sheet. “Plexiglas” is also a brand name. Confirm the sheet type, thickness, and color rather than relying on the trade name.
Can any size be made?
Size is limited by sheet size, handling, and joint length. Very large clear faces often need a thicker panel or a frame so the face does not bow. A sample is the practical check for a new geometry.
How long does a cemented joint need before shipping?
Handling strength can appear within hours. Full solvent loss takes longer and depends on cement, thickness, and temperature. Shipping a freshly cemented box is a common cause of joint marks.
Does a thicker wall always make a safer box?
No. A thick panel with a sharp slot corner, a loose door, or a surface-mounted lock can still fail at the detail. Security is the slot, the door gap, and the lock together.
What should a buyer send for a quote?
Outside size, thickness, color, quantity, slot size, lock type, and a front-view sketch. A photo of a similar box is useful, but the sketch should still state dimensions.
Sources
- ASTM International, ASTM D4802, Standard Specification for Poly(Methyl Methacrylate) Acrylic Plastic Sheet. astm.org/d4802-16.html
- National Library of Medicine, PubChem compound summary for polymethyl methacrylate. pubchem.ncbi.nlm.nih.gov
