Crates, Travel Frames and Handling Kit

Why Crates Exist When Soft Wrap Looks Enough

A painting that sits still on a wall meets one climate and almost no shock. The same painting in transit meets drops, tip-overs, compressive stack loads, vibration from road beds and aircraft holds, and swings of temperature and relative humidity that the Canadian Conservation Institute (CCI) lists among the core shipping hazards. Soft wrap alone controls abrasion and dust. It does little against a corner drop onto concrete or a pallet forklift that shears a carton wall.

The National Gallery of Art’s Art in Transit programme, still taught through AIC and PACCIN crating workshops, treated those forces as design inputs. You size cushions for a probable drop height in the chosen network, then choose a shell strong enough for that network. CCI’s shipment note rates parcel-courier hubs as high to very high hazard and advises packing for drops from heights up to about 2 m. Art-handler door-to-door runs sit at the low end of the same table. The crate you buy or build must match the worst leg, not the brochure photograph of a climate truck.

Crates also solve geometry. An unframed canvas with soft acrylic or heavy impasto cannot take facing pressure. A travel frame creates a rigid collar so wrap and foam touch timber, not paint. Ornate gilt frames that would shred under bubble wrap ride inside an HTS (handling-transportation-storage) frame so contact lands on the travel structure. Sculpture with projections needs carved foam mounts or a double-case layout. The wooden box without those interiors is only a heavy carton.

Wood packaging brings phytosanitary rules once borders appear. Solid wood packaging thicker than about 6 mm that crosses many international borders must meet ISPM 15 heat-treatment and IPPC marking requirements, or customs can hold or reject the shipment. Destination rules change; your crate shop should confirm current treatment marks for the route. Domestic UK or US road moves often skip that stamp, but the same plywood habits still matter for strength and reuse.

Reuse changes the brief. A one-way sale crate can use simpler screw lids and disposable foam cut-outs. A multi-venue loan crate needs numbered positions, durable latches, and a packing diagram a stranger can follow at 9 pm in a loading bay. CCI’s shipment note separates those duty cycles for a reason: repeated open–close cycles punish weak hardware and poorly labelled interiors. If you expect the empty shell to return, say so when you commission; knock-down channel crates and marked foam sets exist for that loop.

Soft Pack, Travel Frame or Full Art Shipping Crate

People use “crate” for three different jobs. Soft pack is primary packaging for a controlled van: wrap, boards, foam corners, sometimes a shallow tray, no full plywood shell. A travel frame (including CCI’s HTS design from National Gallery of Canada practice) is a functional collar that protects edges and keeps materials off the paint face. A full art shipping crate is the outer case: triwall, channel crate, ASTM-style plywood box, or a gasketed climate museum crate. You often nest them: soft pack or travel-framed work floats on foam inside the shell.

Match the tier to network, value and surface. A sturdy contemporary canvas on a shared fine-art shuttle across one city may soft-pack. The same canvas flying as general cargo, or stacked in a commercial freight warehouse, wants durable plywood and thicker foam. Climate lining, desiccant and data loggers belong when the journey includes long outdoor waits, ocean container legs, or works sensitive to relative-humidity swing. Crown Fine Art’s technical notes stress that crate design starts from the object and the full route, including door widths and vehicle beds, so nobody mid-journey is forced into a bad lift.

Soft pack for controlled art-handler routes

Soft pack suits works that will stay with trained handlers, ride upright, and avoid parcel hubs. You still face the paint with glassine or spaced board where the surface allows contact, seal with clean polyethylene where humidity buffering helps, add corner protection, and wrap with closed-cell foam or bubble wrap (bubbles out, never on bare paint). PACCIN preparators document variations such as “tabbing,” where tabs cut into double-wall board or Coroplast secure ornate or awkward frames with Volara pads so contact stays controlled.

Soft pack fails when the package must survive unsupervised drops, stacking on its face, or long outdoor exposure. It also fails when the frame cannot accept any contact pressure. In those cases step up to a travel frame before you argue about plywood thickness. Cadogan Tate’s painting practice often mounts the work in a protective frame inside the crate so packing never bears on the paint film; that logic starts at soft-pack design even when the outer shell comes later.

Travel frames and HTS collars

CCI recommends an HTS travel frame for unframed works, fragile display frames, acrylic surfaces that mark from light contact, and oversized canvases that need rigid edges for handling. The frame is plywood or a light rigid skin on a timber armature. The painting attaches with mending plates, T-nuts or articulated fasteners such as Oz clips so you do not chew the same screw holes on every loan. Sides must extend past the paint plane so polyethylene can stretch across the opening without touching the surface.

A travel frame is not a decorative moulding. It is a handling tool you can leave on in storage. CCI’s handling notes treat HTS frames as the preferred home for large contemporary works with soft or high-impasto surfaces. Measure for hand space between painting and collar so installers can place and remove the work without scraping. Once the painting sits in the travel frame, wrap and cushion as you would a framed work. For short controlled moves, some galleries soft-pack the travel frame alone; for freight, the framed unit goes into a crate.

Full crates: light shells, plywood and climate builds

CCI lists three common in-house shells. Triwall containers (triple-wall corrugated with softwood framing) suit local or high-quality long moves when weight matters. The CCI channel crate breaks down for return shipping and storage. A basic plywood shipping crate following ASTM D6251-type practice uses sanded plywood panels of 9 mm, 12 mm or 18 mm with 19 × 64 mm or 19 × 80 mm cleats; museum shops often treat 12 mm as a practical minimum because panels stay flatter. Loads in that design family run up to about 450 kg when built to the published pattern.

Climate or museum crates add gasketed lids, insulation board, vapour barriers such as aluminium-coated polyethylene (Marvelseal-type films), and interiors cut so the packed unit cannot migrate. AC Fine Art Services and peer shops describe gasketed MDO plywood “museum” crates with rubber seals and insulation for works that need tighter environmental buffering. Double-case systems place a firm inner box on outer corner cushions so fragile surfaces never meet the foam that absorbs the drop. Choose the climate tier when the itinerary includes cargo holds, long tarmac waits, or insurers who specify museum packing for the value band.

Skyframe and similar technical summaries describe the structural habit shared across good shops: plywood skin over an internal cleat frame, often in the 9–12 mm panel range for mid-size work, screwed so the lid opens without the shock of a pry bar. Screws matter. Prying a nailed lid transmits impact into the interior. Recessed hardware survives conveyor edges better than proud bolts. Skids keep the base off wet floors and give pump-truck tines a place to enter. Those details look boring on an invoice and decide whether the crate survives the journey as a system.

Build Specs: Foam, Barriers and Orientation

Crate performance is mostly interior engineering. CCI’s cushioning rule of thumb starts at 50 mm on all sides for many art shipments, rising to 75–100 mm for fragile objects or high-hazard networks. Art-handler door-to-door runs may use 25 mm for robust items and 50 mm when value or fragility is high. Parcel networks demand the thick end of the range because drop heights climb. Thickness alone fails if the foam is overloaded: divide object weight by cushion contact area and keep the static load inside the foam’s published range, or the pad bottoms out and transmits the hit.

The packed unit must act as one firm body floating on softer cushions. Loose stretcher keys, scissoring frames or a painting rattling in an oversized cavity amplify shock. CCI Technical Bulletin 34 and Notes 20/3 both push mounts, travel frames and double cases for that reason. Screw lids rather than nailed lids so opening does not jar the contents. Recess hardware. Add skids and knee-height handles on large crates so handlers raise the load less and forklifts can enter under the base.

Foam grades and how they fail

Closed-cell polyethylene foam (Ethafoam, PolyPlank and similar, often about 33 kg/m³) suits mounts and heavier cushioning because it is chemically stable and carveable. Cross-linked polyethylene sheet (Volara-type) gives a smooth non-abrasive face at contact points. Open-cell polyurethane ester foam cushions well in double-case corner pads but should stay off metals and sensitive surfaces; use it behind a barrier. Extruded polystyrene plank insulates and supports heavy mounts but is less resilient after impact, so treat it as structure and thermal mass rather than the sole shock layer.

Bubble wrap remains useful as outer wrap over sealed polyethylene, with bubbles facing out. Direct bubble contact imprints varnish and soft acrylics. Tissue “mummy wrap” methods that CCI describes for some fragile objects are not for paintings. For paint films, keep facing materials to glassine, unbuffered acid-free tissue, or a spaced rigid board held by the frame rebate or travel collar.

Climate layers, paint and wood chemistry

Typical packaging buffers sudden temperature change for minutes to a few hours only. CCI’s transport temperature specification when control matters is roughly 15°C to 25°C. Insulation board and vapour barriers slow the swing; they do not replace a climate vehicle on a winter night or a summer tarmac. For long sealed storage inside a crate, CCI advises painting interiors with approved acrylic systems and allowing about four weeks’ cure. Avoid oil-based, alkyd and similar interiors that off-gas onto collections. Marvelseal-type liners block moisture and pollutants when journeys or storage periods stretch.

Condition hygroscopic packing materials in the same room as the painting when you can, so cardboard and tissue start at a compatible moisture content. Seal polyethylene wraps so the painting’s own wood and canvas can buffer short humidity changes, provided temperature stays fairly steady. Random silica packs dumped against a face cause local damage; place desiccant where a shipper designs for it, never as improvisation on the paint plane.

Orientation, labels and access geometry

Most stretched canvases travel vertical so fabric does not rest on the paint film. Label every face that handlers will see. Mark glass when relevant. Write unpacking notes inside the paperwork pocket: travel frame stays on until hanging, laminated glass is taped, sensors sit on which faces. CCI advises discrete “fragile” marking and warns against advertising “art” on the exterior. Measure packed depth against door widths, stair turns and van beds before you cut plywood; Crown’s crate writing treats access surveys as part of design, not as the driver’s problem on delivery day.

Materials Table and a Practical Handling Kit

Buy for contact chemistry and mechanical performance. The table below merges CCI Notes 10/16 and 20/3 material lists with common crate-shop practice. Thicknesses and load bands are starting points; raise cushion depth for rough networks.

A handling kit for crate work is small and specific. Clean nitrile gloves for varnish and soft acrylics. Soft pencils and tags for orientation marks on wrap, not on frames. Carton tape with folded pull tabs. A notebook or printed packing list that travels in a pouch on the crate. Camera for outbound and inbound condition. Corner covers. Spare Volara and PE sheet. Measuring tape and a square. For shops: screw guns with clutch settings that will not strip plywood, IPPC-marked timber stock for export jobs, and foam knives or hot-wire tools used away from the object. Day-to-day gallery lifting technique is a separate skill; keep this kit about packing hardware.

Add a clean work surface large enough for the painting plus wrap overlap, and enough clear floor to open the crate lid without resting it on the face. Keep food, solvents and packing chaos out of that zone. Condition cardboard and tissue in the room overnight when the schedule allows. CCI’s wrapping sequence assumes materials share the painting’s recent humidity history; a cold garage roll of cardboard brought straight onto a warm painting fights that buffer. Photograph each layer as you build if the shipment carries insurance weight: face barrier, travel frame, foam layout, closed exterior with indicators visible. That sequence is evidence, not vanity.

Shock Indicators, Tip Sensors and Loggers

Indicators do not soften a drop. They record that a threshold was crossed. ShockWatch-style labels change colour when acceleration exceeds a rated band. TiltWatch-style devices trip when a crate leans past a set angle. Place them where receiving staff can photograph them before opening, and note serial numbers and “armed” status in the shipment file. Colorado Art Services and peer technical notes treat indicators as documentation tools beside sound packing, not as a replacement for foam design.

On arrival, photograph all faces and every indicator before you cut screws. A triggered sensor plus matching damage supports a claim. A triggered sensor with an intact object still tells you the journey exceeded the design assumption; open with care and compare to outbound photos. CCI’s controlled-network logger studies often recorded few or no impact events above low thresholds when packages rode with art handlers; parcel networks look different. Do not invent a false sense of safety from a blank indicator on a poorly packed box.

Temperature and humidity data loggers belong on climate-sensitive loans and high-value routes where the contract specifies environmental limits. Mount them so they measure crate air, not a heater vent on a truck wall. Read them against the agreed band (often near the 15–25°C transport window CCI cites when control is required). Loggers create evidence; they do not cool a hot hold.

Edge Cases That Change the Crate

Standard canvas-in-travel-frame packing fails on several objects. Change the interior rather than forcing one foam recipe.

Heavy impasto and soft acrylic. Texture above the plane cannot take facing pressure. Deepen the travel collar or use a slat/travel crate so materials bridge high points. CCI flags uniformly matte and soft acrylic films for zero finger contact; the same rule applies to wrap.

Panel paintings and joined wood. Shock and humidity differentials open joints. Extra flotation, strict orientation and often a specialist shop are justified even at moderate values. Joined panels need more care than a single plywood panel of similar size.

Ornate gilt and plaster frames. Soft pack can burnish gold. PACCIN discussions favour travel frames or tabbed packs with release films (PTFE/Dartek-type) under pads so gilding never sees abrasive foam. When in doubt, collar the frame and keep all contact off ornament.

Sculpture, ceramics and mixed media. Carve negative mounts, support the heaviest axis, and pad projections with smooth tissue pillows. Double-case layouts keep fragile surfaces off the shock foam. Top-heavy works need cradles that a cardboard soft pack cannot invent on packing day.

Glazing. Annealed glass turns a drop into shards against paint. Prefer laminated glass or acrylic for travel, or remove glass for the journey when a framer and conservator agree. Tape is mitigation for small works, not a guarantee on large panes.

Multi-venue loans. Use screw or latch closures, numbered foam positions and packing diagrams so a second venue can repack correctly. Exhibition crates favour repeated open–close cycles; one-way domestic crates can stay simpler.

International wood packaging. Confirm ISPM 15 / IPPC marks for solid wood on the route. Customs holds are a damage risk of their own. Broader export paperwork belongs with the international shipping guide in this series.

What Professional Crate Shops and Shippers Build

A fine-art crate shop sells risk reduction measured in millimetres and drop heights. Expect a survey: overall height × width × depth including frame, weight, photographs of the reverse, framer details, and access notes at both ends. Crown Fine Art describes asking questions that catch frame-versus-sight-size mismatches before timber is cut. Atelier 4 and peers emphasise PACCIN-trained builders, conservation-grade foams and climate vehicles with air-ride suspension on many routes.

In the workshop, preparators cut travel frames, carve Ethafoam flotation, line shells with vapour barrier where specified, and fit shock or tip indicators. Cadogan Tate’s painting method typically holds the work in a protective frame so the paint film floats free of packing. Museum departments and private collector teams inside large firms design to different duty cycles: loan crates that open ten times versus one-way sale crates that open once.

On collection day, handlers check condition against your report, photograph, pack on site or at the depot, and strap loads so crates cannot tip. Access geometry still rules: a crate that fits the truck may not pivot on a landing. Trade networks such as ICEFAT let a London shop hand to a New York peer without reinventing foam standards. Ask who builds the crate (in-house or subcontracted), whether the quote includes materials, and whether empty crates return.

AIC and PACCIN’s shared Crating 101 and Art in Transit 2.0 teaching lines still push calculated padding for road and air vibration, then hands-on inner packing inside a prefabricated outer shell. That sequence is the professional habit you are buying: measure the hazard, then cut foam, then close the box.

BS EN 15946, the European packing standard for cultural property ready to move, pushes the same discipline in procedural form: packing under owner or custodian supervision, after a condition report, by trained staff, with the object secured according to a risk assessment and marked without advertising contents. Private clients rarely cite the standard by number. Reputable shops still work to its habits: enough hands, a written plan, and markings that help handlers without inviting theft.

What Travel Frames and Crates Cost

Prices move with size, labour, materials tier and rush. Treat the bands below as planning ranges drawn from public fine-art logistics commentary and crate-shop marketing (FairArt, Union Fine Art Services, regional movers), not as quotes.

UK shop rates track the same tiers in pounds once labour and timber are local. Rush fabrication in five days or fewer often adds a premium. Always ask whether the line item includes foam, travel frame, indicators, ISPM 15 timber, packing labour and return of empties. A cheap shell with no interior flotation is a false saving. Dimensional weight on air freight also rises with deep foam; measure the finished exterior before you compare carrier rates.

Budget insurance apart from the crate. Carrier liability and nail-to-nail fine-art cover are different contracts; see the series insurance guide when you price risk.

When to Commission a Crate Maker

Commission a shop when any of these hold: the work’s value or irreplaceability exceeds what you can absorb; the surface cannot take wrap contact; the route includes unsupervised freight, air cargo or stacking; the packed size needs skids, team lifts or access surveys; an insurer or registrar specifies museum packing; or you need ISPM 15-marked wood for export.

Stay with soft pack under a known art handler when the work is stable, the run is short, and both ends have trained staff and clean spaces. Stay with a sturdy double-wall carton and thick foam only for small, sound, low-value works on routes you already trust; that method lives in the shipping guide, not as a plywood substitute for a loan painting.

Call a conservator before anyone cuts foam if paint is lifting, canvas is weak, a panel shows open joins, or soft media sheds. CCI’s travel fitness notes are blunt: consolidate or refuse travel. A crate preserves condition; it does not repair an object that should not leave the wall.

Commission early. Custom crates often need several working days. Measure, photograph and share access constraints in the first email so the shop designs once.

FAQ

What is the difference between a soft pack and an art shipping crate?

Soft pack is the wrap-and-foam primary packaging used on controlled art-handler routes. An art shipping crate is the rigid outer shell (plywood, triwall, channel crate or climate museum case) that resists puncture, stacking and rough handling. Many shipments use both: soft-packed or travel-framed work floating on foam inside the crate.

Do I need a travel frame if the painting already has a display frame?

Use a travel frame when the display frame is fragile, ornate, too shallow to keep wrap off the paint, or when the paint surface cannot tolerate contact. Sound, deep frames with backing boards can soft-pack or crate without an HTS collar. Unframed canvases almost always need a travel collar before cushioning.

How thick should foam be inside a crate?

CCI’s common starting point is 50 mm on all sides, with 25 mm acceptable for robust items in low-hazard art-handler networks and 75–100 mm for fragile works or parcel-level drop heights. Thickness must also match foam load range so pads do not bottom out.

Are shock indicators mandatory?

No, but they are common on higher-value crates because they document mishandling for claims. Place them where receivers can see them, record serials, and photograph status before opening. They do not replace correct cushioning.

Does every wooden crate need an ISPM 15 stamp?

Solid wood packaging thicker than about 6 mm that crosses many borders must meet ISPM 15 heat treatment and IPPC marking. Confirm current rules for your origin and destination with the crate shop. Domestic road moves often skip the stamp; international legs rarely should.

Can I build a museum crate myself?

Skilled makers following CCI or ASTM patterns can build sound domestic plywood crates. High-value, climate-sensitive, multi-venue or export jobs belong with shops that stock conservation foams, vapour barriers and marked timber. A failed DIY crate on a valuable painting costs more than a professional build.

Should paintings travel flat inside the crate?

Prefer vertical orientation for most stretched canvases unless a conservator or shipper specifies otherwise. Label the crate so handlers keep that attitude. Panels and special constructions may need a fixed orientation called out on every face.

What belongs in a basic packing and handling kit for crate work?

Gloves suited to the surface, glassine or tissue, clean polyethylene, closed-cell foam sheet, corner covers, carton tape with pull tabs, measuring tools, camera, packing list pouch, and orientation markers. Add shock indicators and vapour-barrier film when the crate design calls for them. Lifting choreography for stairs and installs sits in the handling article in this series.