8 Archival Acrylic Display Cases for a 4-Month Museum Traveling Exhibit

The Brief

The buyer was a mid-size US regional museum preparing a 4-month traveling exhibit built around a sensitive paper-and-textile artifact group. The exhibit would visit 6 venues over the tour, with venue dwell times ranging from 10 to 21 days and an average of 14. Most venues were repurposed historical buildings — three had skylights, two had west-facing windows, and only one offered active humidity control rated for conservation work.

The RFQ specified two non-negotiable numbers we'd seen before in archival work but rarely in traveling-exhibit requests: UV transmission below 5% across the 380–400nm band, and delta-E ≤ 1.5 over a 12-month accelerated UV chamber test. The first number protects the artifact during display; the second proves the case itself won't yellow or shift hue inside the tour window. Both align with the Smithsonian Conservation archival display guidance for sensitive paper and textile, and the chamber protocol maps to ASTM G154 cycle 1 (xenon-arc, condensation cycle).

• UV control end-to-end. Five of six venues had unmanaged daylight reaching the gallery floor at some hour of the day. The case had to do the protective work the venue wouldn't.
• Humidity buffering without venue infrastructure. Five of six venues couldn't power a continuous humidification system. We needed a passive solution that held 45–55% RH for an entire venue stop without intervention from a registrar who wasn't on staff.
• 4-month tour-ready, including 4 long-haul truck moves. The case had to survive both the gallery and the road. Crating mattered as much as the optics.

Our Recommendation

We walked the curatorial team through three material paths during spec review. They came in expecting laminated glass with a UV interlayer; we made the case for UV-grade cast PMMA as the better total package for a traveling exhibit, with two coatings layered on top.

UV-grade cast PMMA with 380–400nm absorber

Standard cast PMMA already blocks most of the UV-B band on its own, but transmission climbs sharply in the UV-A region above 360nm — exactly where pigment fading and paper embrittlement still happen. We specified a UV-grade cast formulation with an in-batch absorber tuned to push transmission below 5% across 380–400nm. In our 12-month xenon-arc chamber test (ASTM G154 cycle 1), the UV-grade material held delta-E ≤ 1.5; a standard cast PMMA control coupon hit delta-E 5+ within 90 days under the same profile.

For a tour, weight matters too. Cast PMMA is roughly half the mass of laminated glass at the same panel size. For 8 cases moving across 4 truck legs, that's a meaningful change in per-leg crate weight and in how venue staff handle install.

AR coating — and why we recommended it for this exhibit

Anti-reflective coating wasn't in the original RFQ. We added it during the recommendation pass because three of the six venues had skylights or window light reaching the gallery, and uncoated polished PMMA reflects roughly 8% of incident light per surface. That reflection makes a 14-point exhibit label unreadable from a normal viewing distance under angled daylight. AR coating cuts surface reflection to about 0.9% — the difference between curator approval and curator rejection at spec review.

Climate-sealed base with replaceable silica-gel buffer

For humidity, we ruled out continuous active humidification early — five of six venues couldn't supply power or a registrar to monitor it. Instead, we recommended a climate-sealed base with a swappable silica-gel cassette pre-conditioned to 50% RH. Following the ISO 18934 reference profile for archival enclosures, our bench tests showed the cassette held the case interior at 45–55% RH for 8–12 weeks before re-saturation, depending on venue ambient humidity. With a 14-day average dwell time per venue, that gave the registrar a comfortable margin and a clear swap point between venue 3 and venue 4.

The base itself is a sealed cavity below the display deck, with an EPDM gasket at the deck-to-base interface and a screw-access hatch on the underside for cassette swap. No daylight visible from the gallery side; no field-serviceable seam for a venue contractor to mishandle.

The Spec, Layer by Layer

The final case was a 5-layer build, with each layer doing one job and only one job. The cross-section below maps each layer in viewing order from the gallery side inward.

The optical stack (layers 1–2) handles UV and reflection. The mechanical stack (layers 3–4) handles sealing and structure. The conditioning stack (layer 5) handles humidity passively. Most museum display cases combine functions across layers; we keep them separate so when one layer needs attention, the registrar can identify and address it without having to send the case back to us.

Production and Crating

Production ran 30 days. The bottleneck wasn't fabrication — cast PMMA cell-casting and CNC edge work fit comfortably inside three weeks for 8 cases — it was the chamber test. We ran a coupon from the same casting batch through a 12-month accelerated xenon-arc cycle on the bench in parallel, and spectrophotometer-verified delta-E and UV transmission before approving the cases for crating. That dedicated chamber slot is what pushed the schedule from 22 to 30 days.

Crating mattered as much as the case itself. Eight cases would move on four long-haul truck legs over four months. We modeled custom closed-cell foam molds for each case, with a cradle for the climate base and a separate well for the optical stack. Total crating cost added 4% to the project — a number we were prepared to defend against value-engineering, because case-replacement risk at venue swap would have dwarfed the savings.

Spec sign-off package

Before shipping, we sent the registrar a sign-off package with the chamber test report, UV transmission curve, AR coating spec sheet, gasket material data, and a venue-swap procedure for the silica-gel cassette. Curatorial approval came through inside three working days — the package answered the questions the conservator was going to ask.

Install and 4-Month Tour

The first venue received its allocation 9 days before opening. That gave the registrar time to pre-condition the silica-gel cassettes on-site, verify RH inside each case at 24 and 48 hours after deck seal, and flag any case that needed adjustment before the artifact group went in. Eight cases passed; none needed intervention.

Across the 4-month, 6-venue tour, we tracked three things with the registrar: in-transit damage, interior RH stability, and curatorial sign-off at each new install. The numbers held.

The silica-gel cassette swap landed exactly where the bench tests predicted — between venue 3 and venue 4, at week 9 of the tour. The registrar swapped all 8 cassettes in a single afternoon during install at venue 4 using the screw-access hatch on the base underside. No case had to be opened from the gallery side; the artifact group never lost its conditioning envelope.

"We came in expecting laminated glass and walked out with a better case at lower weight. The chamber test report answered our conservator's questions before she finished asking them, and the silica-gel cassette swap took an afternoon. Eight cases, four months, six venues, zero damage."

Lessons and the Permanent Collection Expansion

Two lessons from this project carried into how we now scope museum traveling-exhibit work. First, the UV transmission number is a floor, not a ceiling — the chamber test is what proves the case will hold the number for the life of the tour, and we now run that test in parallel with production on every museum order rather than only when the RFQ asks for it. Second, crating is part of the spec, not a logistics afterthought. The 4% crating premium has a different shape on a balance sheet than it does in a registrar's incident report.

The same museum is now in spec review for 16 additional cases for their permanent collection, built on the same 5-layer geometry. With the casting tooling and CNC programs already approved, repeat-order production drops from 30 days to 22. The conservator's spec sheet for the permanent install is the traveling-exhibit spec sheet with two changes: heavier base mass for fixed-floor stability, and a slightly larger silica-gel cassette for the longer dwell time between scheduled re-conditioning.