The question we get about outdoor preservation is never whether the film keeps rain off. It is whether the wrap will still be there after a season of Midwest wind, ice and sun, or whether somebody will drive past the yard in March and find blue plastic in the fence line and a rusted gearbox in the open. Tarps fail that test every winter. A shrink film only earns its place if it stays sealed for the whole lay-up.
The most direct evidence we can offer is what happens to MilCorr VpCI Shrink Film when the weather is worse than anything Illinois can produce: a U.S. Air Force test through three 2004 hurricanes, an offshore rig through a near-direct hurricane hit in 2017, three 158-tonne cable drums wrapped in a North Sea winter, and the two-year rule a Gulf Coast crew uses to choose between MilCorr and the lighter VpCI-126 HP UV film.
Three hurricanes in one summer: the U.S. Air Force test
Cortec’s shrink-film brochure describes a long-term evaluation the U.S. Air Force ran on MilCorr over aircraft cargo loaders, equipment that must stay in inventory for up to 30 years. The loaders were wrapped and left outdoors for six months to three years. In August 2004 the site was hit by Hurricane Charley, a Category 4 storm with 150 mph winds, then by Frances (Category 2, 105 mph) and Jeanne (Category 3, 120 mph). When the test closed in April 2007 the film showed minor cuts and abrasions and nothing more, and the loaders met every test parameter. That is why MilCorr, 10 mil, opaque and UV-stabilized, is the only packaging film in Cortec’s consultation guide rated for outside, uncovered storage.
An offshore rig through Hurricane Harvey
Cortec Case History #662 (2015) covers a Gulf of Mexico drilling rig that an offshore drilling contractor mothballed when the market turned. A preservation crew wrapped the large outdoor assets in MilCorr: the hydraulic power unit, a heat exchanger, the helicopter fuel station, motors, blowout-preventer components, pumps and control panels. Equipment under cover went into VpCI-126 HP UV. Every wrapped panel got VpCI-105 or VpCI-111 emitters, VpCI-130 foam or VpCI-308 pouches inside, sized by volume, and VpCI-391 and VpCI-368 were sprayed over painted equipment and handrails.
In 2017 the rig took an almost direct hit from Hurricane Harvey. When the crew came back in summer 2019 for the routine reapplication check, every MilCorr wrap was still in place and nothing under it had rusted. Around the same time the hydraulic power unit had to go back into service; it was returned by cutting the film open in a few places and starting it up.
Three 158-tonne cable drums in a North Sea winter
Cortec Case History #800 (2022) is the same film at the other end of the weather scale. A Norwegian energy company needed three emergency power cable drums, 158 tonnes each, stored indefinitely on the coast at Stavanger in salt spray, rain, wind and UV. UV damage to the cable was the main worry, corrosion of the steel frames the second.
Each drum was lifted onto a sheet of MilCorr, further sheets were wrapped over and fused to the base sheet, and the whole thing was heat-shrunk. Every seam was reinforced with shrink tape, lifting-lug openings were cut and taped, and zipper panels were fitted low on each drum for inspection. The crew worked in freezing temperatures, strong wind and heavy snow. The drums are preserved until needed, with re-wrapping under consideration at five to ten years.
| Case | Exposure | Film | Time in service | Outcome |
|---|---|---|---|---|
| U.S. Air Force loaders (2004 to 2007) | Three hurricanes, up to 150 mph | MilCorr | 6 months to 3 years | Minor cuts and abrasions; all parameters met |
| Offshore rig, #662 (2015) | Near-direct hurricane hit, 2017 | MilCorr; 126 HP UV under cover | 4 years to inspection | All film intact; no rust |
| Cable drums, #800 (2022) | North Sea salt spray, wind, snow, UV | MilCorr, taped seams | Indefinite; review at 5 to 10 years | Preserved; zipper inspection panels |
The two-year rule for picking the film
Cortec Case History #837 (2024) describes a mobile preservation team that visits an oil company’s repair shops between Houston and New Orleans, where rebuilt pumps, gearboxes and compressors leave without anyone knowing whether they go straight to a platform or sit in a warehouse. The team treats electricals, voids, gearboxes and fasteners with the matching sprays, emitters, pouches and additives, then one rule sets the outer wrap: VpCI-126 HP UV shrink film if the unit is headed offshore or will be stored two years or less, MilCorr if it will sit outdoors or in a warehouse for more than two years. By June 2024 the team had made about 60 visits to more than 10 facilities and preserved 70 to 80 parts.
How to do this in your plant
- Decide the term first. Up to two years outdoors, VpCI-126 HP UV shrink film (we order it in). Longer, or no end date, MilCorr 20 by 210 ft, or the 20 by 100 ft roll for a single unit.
- Clean and dry the equipment in a Build-All or Magido washer or with a VpCI pressure-wash cleaner, and derust anything active. A film seals in whatever is under it.
- Treat the insides before you close the outside. One VpCI-111 emitter per 11 ft³ of control panel; one VpCI-308 pouch per 35 ft³ of casing, tank or crate; VpCI-391 over painted surfaces for three years or more.
- Size, pad and seam the film per our MilCorr shrink-wrap guide: 12 to 24 inches of overlap, seam over a support, sharp edges padded, film shrunk at 340 to 440 °F in short passes from the bottom up.
- Tape every seam, lug opening, patch and door with 3M shrink tape, one roll per roll of film. The drums and the rig came through because the seams were closed, not because the film was thick.
- Fit a zipper door over a void space if you will need to inspect, keep vents to the minimum, and walk the wrap after the first storm and once a season after that.
Which Cortec products
- MilCorr VpCI Shrink Film, 20 by 210 ft: 10 mil, opaque, UV-stabilized, rated five years or more outdoors; the standard roll.
- MilCorr VpCI Shrink Film, 20 by 100 ft: the same film in a half roll for one or two machines.
- 3M white shrink tape, 4 in by 108 ft: seams, lug openings, patches and zipper doors.
- VpCI-308 pouch: multi-metal vapor charge for casings, tanks and crates, one per 35 ft³, up to 24 months sealed.
- VpCI-111 emitter: self-stick cup for control panels, one per 11 ft³, up to 24 months.
- VpCI-391: non-tacky temporary coating sprayed over painted equipment under the wrap.
We stock MilCorr, shrink tape, VpCI-308 pouches and VpCI-111 emitters in Elmhurst, Illinois, and can order VpCI-126 HP UV film and zipper doors against a job. If you have a machine or a skid that has to sit outside through a Midwest winter, contact us with the dimensions and the term and we will size the film, send samples, or wrap the first unit with you.
Sources: Cortec Case History #662 (2015), Cortec Case History #800 (2022), Cortec Case History #837 (2024); Cortec VpCI Shrink Film brochure (U.S. Air Force cargo-loader test, 2004 to 2007); Cortec product data sheets for MilCorr VpCI Shrink Film, VpCI-308 and VpCI-111.
