Description
VpCI®-375 is a water-based acrylic that is primer and topcoat in one, and the highest published salt spray figure in Cortec’s coatings line — over 2,500 hours on carbon steel. The red oxide 5-gallon pail covers roughly 640 to 1,070 sq ft per coat at 3 to 5 mils.
VpCI-375 is for structural steel and equipment that will sit outdoors, unsheltered, and cannot come back for a second coating system: a single product, applied direct to metal, that delivers the corrosion resistance of a primer-plus-topcoat system at under 1 lb/gal VOC and with water cleanup. Cortec’s brochure lists it for harsh, outdoor, unsheltered service, and the Product Consultation Guide rates it 4 (outside, uncovered storage) on carbon steel, stainless steel, cast iron, aluminum, galvanized steel, copper, brass and solder; on aluminum, galvanized or plated substrates apply VpCI-373 wash primer first. Cortec quotes less than 1 lb/gal VOC for its water-based coatings against more than 3 lb/gal for conventional solvent-borne systems, which matters for shops working under an air permit. Keep it from freezing.
Typical applications
- Harsh outdoor unsheltered structures
- Combined primer and topcoat in one system
- Multi-metal corrosion protection
- Structural steel, racks, frames and skids stored or installed outdoors
- Tank exteriors, piping and equipment housings
- Maintenance repainting where one coat must do the job
- Power plant and utility equipment maintenance programs
How to apply VpCI-375
- 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. 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. VpCI-375 may be thinned with water up to 10 % by volume to adjust viscosity.
- Conditions. Apply between 45 and 90 °F (7 to 32 °C) with the surface at least 5 °F (2 °C) above the dew point. Water-based coatings need the cleaner surface and the drier air; do not apply in falling temperature or high humidity.
- 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 3.0 to 5.0 mils (75 to 125 µm) dry per coat. Coverage is 128 to 214 sq ft per gallon at 3 to 5 mils. The published salt spray and humidity results were run at 4.0 to 4.5 mils, so build to that range for full performance.
- Drying. Dry to touch in about 20 minutes at 77 °F at 3 mils and dry to handle in about 40 minutes; recoat between 40 minutes and 72 hours, sanding after that. Force-dry 15 to 20 minutes at 150 °F (65 °C) if needed. Full cure takes 7 days at 77 °F (25 °C) and 55% RH.
- Cleanup. Clean tools with water while wet; once dry use butyl cellosolve or MEK, following the solvent manufacturer’s safety directions.
- Storage. Keep the container sealed, do not let it freeze and do not store above 100 °F (38 °C). Shelf life is 1 year.
- 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-375 is the one-coat system. VpCI-386 is the faster-drying, weldable water-based acrylic topcoat with higher gloss for production lines; VpCI-395 is the two-component water-based epoxy primer for immersion service; VpCI-396 moisture-cure urethane handles marginally prepared steel; VpCI-371 covers hot surfaces. Use VpCI-373 under it on aluminum and galvanized. For rusted steel that cannot be blasted, derust with VpCI-422 or convert the rust with CorrVerter; where blasting is possible, an abrasive blast room gets you to SSPC-SP6 fastest. Browse the full Cortec VpCI line.
Field notes
An Illinois refrigeration-coil maker’s solvent-based paint smelled, posed health hazards and under-performed on corrosion. The coils are now lowered into a large circulating dip tank of VpCI-386, covered when idle, for better corrosion performance, lower VOC and a safer shop. (Cortec Case History #616)
A Spooner, Wisconsin aerosol filler had rusting tanks and piping feeding its line, and NFPA rules require tank farms be protected from corrosion. The crew degreased with VpCI-415, pressure-washed, brushed CorrVerter on the rusted areas and sprayed VpCI-386 White as the topcoat, finishing four tanks and 200 ft of piping in about three days. (Cortec Case History #365)
A Texas tube mill needed a clear zero-VOC OD coating at 1 mil that force-dries fast enough for electronic stenciling. In four trials from October 2020 to June 2022, EcoShield VpCI-386 FD was applied at 1.0 to 1.2 mils after hydrotest and force-dried 22 minutes at 140 °F; several hundred pipes sat a year in a Gulf Coast yard with 5B adhesion and no OD rust, at 0.04 lb per gallon (5 g per L) VOC. (Cortec Case History #783)
Specifications
| Salt spray (ASTM B117) | 2,500+ hours at 4.0–4.5 mils on carbon steel |
|---|---|
| Humidity (ASTM D1748) | 2,000+ hours at 4.0–4.5 mils |
| Water immersion (ASTM D870) | 312 hours at 4.0 mils |
| VOC | 0.68–0.8 lbs/gal (81.3–96 g/L) |
| Recommended DFT | 3.0–5.0 mils per coat (75–125 microns) |
| Coverage | 128–214 ft²/gal at 3–5 mils |
| Dry to touch | 20 minutes @ 77°F at 3 mils |
| Pencil hardness | H; adhesion 5B |
| Type | Water-based acrylic, primer and topcoat in one, direct to metal; permanent coating |
| Color | Red oxide |
| Non-volatile content | 40–52% |
| Gloss (ASTM D523) | 50 maximum |
| Viscosity | 800–4,000 cPs at 77 °F (25 °C) |
| Weight per gallon | 8.5–10.2 lb (1.01–1.22 kg/L) |
| Flash point | >200 °F (93 °C) |
| Temperature resistance (fully cured) | −150 to 350 °F (−78 to 180 °C) |
| Flexibility (ASTM D522) | ½″ 180° bend |
| Dilution | Water, up to 10% by volume |
| Dry to handle | 40 min |
| Recoat | 40 min – 72 hr; sand thereafter |
| Force dry | 15–20 min at 150 °F (65 °C) |
| Full cure | 7 days at 77 °F (25 °C), 55% RH |
| Surface preparation | Clean and contaminant-free; NACE No. 3 / SSPC-SP6 on structural steel; VpCI-373 wash primer on aluminum, galvanized or plated |
| 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 |
| Storage | Sealed container, protect from freezing, below 100 °F (38 °C); shelf life 1 year |
| Minimum order quantity | 4 |
| Size | 5 Gallon Pail |
| Shipping weight | 53 lb (24.0 kg) |
| Availability | In stock |
| Cortec product number | 12410043 |
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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