Description
VpCI®-396 is a single-component moisture-cure urethane that works as primer and topcoat in one coat, direct to metal. Cures with atmospheric moisture — apply between 20 and 80% RH. The 5-gallon pail covers roughly 1,500 to 2,250 sq ft at the recommended film.
VpCI-396 is the coating for steel that cannot be brought to a commercial blast: an aluminum-filled moisture-cure urethane that Cortec’s brochure describes as a hard, flexible primer for marginally prepared structural steel, and that works as primer and topcoat in one. It is one of only two Cortec coatings rated 5 (immersion service in corrosive liquids such as salt water or crude oil) in the Product Consultation Guide, on carbon steel, stainless steel, cast iron, aluminum and galvanized steel; it is not rated for copper, brass or solder. Because it cures by reacting with atmospheric moisture, it tolerates the cold, damp conditions that stop water-based coatings, and it can be topcoated with most conventional urethanes. It is solvent-borne at 3.1 lb/gal VOC with a 77 °F flash point, so it ships as a flammable liquid.
Typical applications
- Structural steel
- Production line items
- Harsh outdoor unsheltered applications
- Immersed structures — ballast, storage and holding tanks
- Over CorrVerter on marginally prepared surfaces
- Transmission towers, bridges and outdoor steelwork repainted in place
- Generator, turbine and plant equipment maintenance
- Primer under conventional urethane topcoats
How to apply VpCI-396
- 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. Where a blast is not possible, hand- or power-tool clean to remove loose rust and scale; on heavier rust apply CorrVerter first and topcoat with VpCI-396. On aluminum, galvanized or plated substrates apply VpCI-373 at 0.5 to 1.0 mil first and test adhesion.
- Mixing and dilution. Power-agitate to a uniform consistency with a squirrel-cage or drill mixer so the aluminum pigment is suspended. VpCI-396 may be thinned with xylol or t-butyl acetate up to 10 % by volume.
- Conditions. Apply between 45 and 90 °F (7 to 32 °C) with the surface at least 5 °F (2 °C) above the dew point. Relative humidity must be between 20 and 80 %: below 20 % the coating will not cure, above 80 % it cures too fast. Cortec’s data sheet allows application above 32 °F (0 °C) and below 120 °F (50 °C). Ground the equipment; flash point is 77 °F (25 °C).
- 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.
- Film build. Apply 2.0 to 3.0 mils (50 to 75 µm) dry, 3.5 to 5.3 mils wet. Theoretical coverage is 901 sq ft per gallon at 1.0 mil DFT, so plan on roughly 300 to 450 sq ft per gallon at the recommended film.
- Drying. Dry to touch in 2 to 3 hours and dry to handle in 4 to 6 hours; recoat or topcoat from dry-to-touch up to 72 hours, sanding after that. Force-dry 15 to 20 minutes at 150 °F (65 °C) if needed. Full cure takes 3 to 7 days; allow full cure before immersion.
- Cleanup. Clean tools with butyl acetate while wet; once dry use butyl cellosolve or MEK, following the solvent manufacturer’s safety directions.
- Storage. Keep the container sealed and do not store above 100 °F (38 °C). Partially used containers must be purged with nitrogen before resealing or the moisture in the headspace will cure the remainder. Shelf life is 1 year. Not freeze-sensitive.
- 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-396 is sold in a 1-gallon can and a 5-gallon pail. The other immersion-rated Cortec coating is VpCI-395, a two-component water-based epoxy primer with 0.2 lb/gal VOC that needs a clean blast and a hardener. For atmospheric service on well-prepared steel the water-based acrylics VpCI-386 and VpCI-375 are simpler and lower in VOC; VpCI-371 covers hot surfaces. On rusted steel, CorrVerter converts what is left after hand-tool cleaning and VpCI-396 goes over it; where blasting is possible, an abrasive blast room gets you to SSPC-SP6 and lets the lower-VOC coatings do the job. Browse the full Cortec VpCI line.
Field notes
A state railway in Serbia treated 200 catenary piers at two stations without blasting: wire brush, CorrVerter by brush or roller at 40 to 60 µm dry film with at least 10 hours’ drying, then two coats of VpCI-396 Aluminum at 80 to 100 µm each. The railway adopted the system as its standard. (Cortec Case History #638)
A Minnesota township extended the life of a plow and salt truck with VpCI-415 pressure wash, VpCI-105 emitters under the dash, ElectriCorr VpCI-239 on electrical contacts, CorrVerter hand-painted on rust, VpCI-368 D pump-sprayed on the undercarriage, VpCI-369 on hinges and moving parts and VpCI-396 rolled onto the salt box, at far lower cost and labor than the alternatives. (Cortec Case History #175)
A Minnesota township refurbished four buried 8 by 10 foot steel lift stations, 40 to 50 years old and reached through 15 to 20 foot tubes that trap humidity: wire brush, power wash and fan dry, VpCI-387 on the walls, VpCI-396 on the floor, and VpCI emitters hung in the housing and inside the electrical panels. (Cortec Case History #274)
Watch: Cortec coatings technology
Video by Cortec Corporation.
Specifications
| Salt spray (ASTM B117) | 750 hours |
|---|---|
| Humidity (ASTM D1748) | 1,000 hours |
| VOC | 3.1 lbs/gal (371 g/L) |
| Volume solids | 56.20% |
| Recommended DFT | 2.0–3.0 mils (50–75 µm) |
| Coverage | 901 sq.ft/gal @ 1.0 mil DFT |
| Pencil hardness | 2H; adhesion 5B; flexibility ½″ mandrel |
| Application window | 20–80% RH, above 32°F (0°C) and below 120°F (50°C) |
| Note | Partially used containers require nitrogen purging. Shelf life 1 year |
| Type | Single-component moisture-cure urethane, aluminum filled, primer and topcoat in one; permanent coating |
| Gloss (ASTM D523) | 30–50 |
| Recommended WFT | 3.5–5.3 mils (88–130 µm) |
| Viscosity | 55–65 s+ Zahn #3 |
| Weight per gallon | 9.39 lb (1.13 kg/L) |
| Flash point | 77 °F (25 °C) — flammable liquid, hazmat shipping applies |
| Dilution | Xylol or t-butyl acetate, up to 10% by volume |
| Dry to touch / dry to handle | 2–3 hr / 4–6 hr |
| Recoat | After dry to touch (2–3 hr) up to 72 hr; sand thereafter |
| Force dry | 15–20 min at 150 °F (65 °C) |
| Full cure | 3–7 days |
| Surface preparation | NACE No. 3 / SSPC-SP6 preferred; tolerates marginally prepared steel; over CorrVerter on rusted steel; VpCI-373 wash primer on aluminum, galvanized or plated |
| Application temperature (guide) | 45–90 °F (7–32 °C), surface 5 °F above dew point |
| Metals | Carbon steel, stainless steel, cast iron, aluminum, galvanized steel; not rated for copper, brass or solder |
| Consultation guide rating | 5 – immersion service |
| Topcoats | Cortec VpCI-280, 380, 381, 382, 384, 386, 387, 390 and 392; check compatibility before applying other solvent-based topcoats |
| Storage | Sealed container, below 100 °F (38 °C); nitrogen-purge partial containers; not freeze-sensitive |
| Size | 5 Gallon Pail |
| Shipping weight | 52.5 lb (23.8 kg) |
| Availability | In stock |
| Cortec product number | 12400946 |
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.
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