Wax-Like Temporary Coating, MIL-PRF-16173E Grade 1 – 55 Gallon Drum (Cortec® VpCI®-368 M)

Description

VpCI®-368 M is the military-specification grade of VpCI-368 — the same dry-to-touch removable waxy film, qualified to MIL-PRF-16173E Grade 1. It is carried on the DLA Qualified Products List with assigned National Stock Numbers. Buy it when a defense, shipbuilding or government purchase order names the specification; buy standard VpCI-368 when it does not. The 55-gallon drum feeds a dip tank or airless rig on a preservation line and covers roughly 3,600 to 5,400 sq ft at the recommended film.

VpCI-368 M is the grade to specify when the contract calls out MIL-PRF-16173E Grade 1, the hard-film corrosion preventive compound class. The film is the same translucent, waxy, scratch-resistant and self-healing coating as standard VpCI-368, and it is on the qualified products list. It gives up to two years of continuous protection outdoors, so it suits flanges, pipe ends, machined faces and whole assemblies that will sit uncovered, ride on a deck or go through a cold-climate winter. In the Cortec Product Consultation Guide VpCI-368 is rated 4 (outside, uncovered storage) on carbon steel, stainless steel, cast iron, aluminum, galvanized steel, copper, brass and solder. It is a solvent-borne coating at 2.9 lb/gal VOC, so check your air permit; when a low-VOC film will do the job, the water-based VpCI-389 is the alternative.

Typical applications

• Flanges and pipe ends
• Machined surfaces
• Equipment layups
• International shipments
• Marine and offshore assets
• Low-temperature climates
• Uncovered outdoor storage of spare parts, valves, pumps and gearboxes
• Export packaging of heavy equipment, alone or under MilCorr shrink film
• Defense and government contracts requiring a MIL-PRF-16173E Class I, Grade 1 hard-film preservative

How to apply VpCI-368 M

1. Surface preparation. The substrate must be free of grease, oil, dirt, fingerprints, drawing compounds, rust inhibitors and anything else that would affect adhesion. Cortec recommends VpCI-440 or a similar phosphatizing pretreatment on production lines and a minimum of NACE No. 3 / SSPC-SP6 commercial blast on structural steel. No wash primer is needed on aluminum or galvanized steel for this product.
2. Mixing and dilution. Power-agitate to a uniform consistency with a squirrel-cage or drill mixer. VpCI-368 M may be thinned with mineral spirits up to 10 % by volume to adjust viscosity; ask Cortec or us before going further. If you would rather not thin on site, VpCI-368 D is supplied ready to spray.
3. Conditions. Apply between 45 and 90 °F (7 to 32 °C) with the surface at least 5 °F (2 °C) above the dew point. The product is not freeze-sensitive, so it can be stored and shipped in unheated space.
4. Equipment. Spray, roll, brush or dip. HVLP or conventional spray: 0.009 to 0.021 in tip, 45 to 55 psi air and 10 psi fluid, 3/8 in ID fluid hose no longer than 50 ft, dual-regulated pot kept at gun height. Airless or air-assisted airless: 0.015 to 0.035 in tip, 1,800 to 2,500 psi, 3/8 in ID hose (a 1/4 in whip end is fine) no longer than 100 ft. Tip size depends on pressure and viscosity.
5. Film build. Apply 2.0 to 3.0 mils (50 to 75 µm) dry, which is 3.3 to 4.9 mils wet. Theoretical coverage is 978 sq ft per gallon at 1.0 mil DFT, so plan on roughly 325 to 490 sq ft per gallon at the recommended film.
6. Drying. Dry to touch in 5 to 7 hours at ambient conditions; force-dry 15 to 20 minutes at 150 °F (65 °C) if needed. Full cure takes 3 to 7 days. No recoat interval is specified because it is a single-coat preservative.
7. Cleanup. Clean tools with butyl acetate while the coating is wet; once dry use butyl cellosolve or MEK, following the solvent manufacturer’s safety directions.
8. Removal. For a film at the recommended DFT: spray the surface generously with VpCI-414 at 60 % in water (the coating-removal strength on the VpCI-414 data sheet), let it sit 10 to 15 minutes, then power-wash at 115 to 160 °F (46 to 71 °C) and 50 to 300 psi. Repeat until the coating is gone. VpCI-414 is the alkaline cleaner Cortec specifies for stripping its temporary coatings; the EcoAir VpCI-414 aerosol handles small areas.
9. Storage. Keep the container sealed and do not store above 100 °F (38 °C). Flash point is 158 °F (70 °C).
10. See the Cortec coatings application guides and comparison table for the shared spray, prep and storage instructions across the Cortec coating range.

Where it fits in the Cortec line

VpCI-368 is the waxy, dry-to-touch member of Cortec’s temporary coating family. VpCI-369 is the oil-based sibling that stays a wet film and also lubricates, useful on chains, threads and moving parts. VpCI-389 is the water-based, low-VOC waxy film for outdoor use and VpCI-391 the non-tacky water-based film that can be welded through. VpCI-368 D is the pre-diluted version; VpCI-368 M is the MIL-PRF-16173E Grade 1 grade; the CorShield VpCI-368 aerosol covers touch-up and small parts. The specified remover is VpCI-414. Browse the full Cortec VpCI line.

Field notes

An East Chicago, Indiana boiler-equipment manufacturer needed an outdoor rust preventive that would take rain, ice, snow and sand abrasion yet remove easily. VpCI-368 diluted 1:3 with mineral spirits, sprayed over heat exchangers, castings and large bearings without first removing the cutting oil, gave better outdoor protection, easier removal and a self-healing film. (Cortec Case History #032)

A Houston air-cooler manufacturer found its nitrogen-purged bundles leaked as the steel blinds contracted in temperature swings. It switched to fogging VpCI-337 into the bundles and sealing with PVC bumper gaskets, with flange faces de-rusted with VpCI-423 gel, degreased with VpCI-414 and sprayed with CorShield VpCI-368. No hermetic seal is needed. (Cortec Case History #823)

Two land rigs in Iraq were stacked for shipment home by the drill crew: VmCI-307 inside major equipment for mixed-metal internals, VpCI-309 mixed with water and flushed through the mud tanks, VpCI-609 in ferrous piping, VpCI-368 on exposed metal, VpCI-369 on rotating equipment and VpCI-111 emitters in cabinets. (Cortec Case History #633)

Specifications

Protection	Up to 2 years of continuous corrosion protection
Film	Dry-to-touch, removable, waxy
Removal	Removable with an alkaline cleaner
Type	Solvent-based temporary (removable) coating, military qualified; conforms to MIL-PRF-16173E Class I, Grade 1
Salt spray / humidity	1,500 hours ASTM B117 / 2,500 hours ASTM D1748
VOC	2.9 lbs/gal (347 g/L)
Coverage	978 ft²/gal @ 1.0 mil DFT (24 m²/L @ 25 µm)
Recommended DFT	2.0–3.0 mils (50–75 µm)
Volume solids	61%
Recommended WFT	3.3–4.9 mils (84–123 µm) for 2.0–3.0 mils DFT
Viscosity	2,000–5,000 cPs
Weight per gallon	7.6 lb (0.91 kg/L)
Flash point	158 °F (70 °C)
Dilution	Mineral spirits to adjust viscosity; ask Cortec Technical Service for the ratio
Dry to touch	5–7 hours
Force dry	15–20 min at 150 °F (65 °C)
Full cure	3–7 days
Surface preparation	Clean and contaminant-free; NACE No. 3 / SSPC-SP6 on structural steel; no wash primer needed
Application temperature	45–90 °F (7–32 °C), surface 5 °F above dew point
Metals	Carbon steel, stainless steel, cast iron, aluminum, galvanized steel, copper, brass, solder
Consultation guide rating	4 – outside, uncovered storage
Removal procedure	VpCI-414 at 60% for coating removal, let stand 10–15 min, then power wash at 50–300 psi and 115–160 °F (46–71 °C)
Shelf life	2 years
Storage	Original packaging, indoors, out of direct sunlight, 40–100 °F (4–38 °C)
Military specification	MIL-PRF-16173E Class I, Grade 1 — on the DLA Qualified Products List (QPL)
NSN	8030-00-062-6950; 8030-00-231-2345; 8030-00-244-1299 (one further 8030-00-244- NSN is listed on the DLA QPL)
Size	55 Gallon Drum
Shipping weight	448 lb (203 kg)
Availability	In stock
Cortec product number	12301468

Solvent Recycling Systems is an authorized Cortec® distributor. See the full Cortec VpCI line, browse the VpCI product selection guide, or contact us for volume pricing and lead times.