Water-Based Removable Coating for Outdoor Use – 5 Gallon Pail (Cortec® VpCI®-389)

Description

VpCI®-389 is a fast-drying water-based removable coating rated for harsh, unsheltered outdoor service — at 0.1 lbs/gal VOC, which is essentially nothing for an outdoor coating. The 5-gallon pail has a theoretical coverage of roughly 3,000 sq ft at 1 mil dry, enough for a machine or a run of fabrications before shipment.

VpCI-389 is the water-based answer to the solvent-borne waxy temporary coatings that have protected equipment in storage yards for decades. It leaves a translucent, waxy, slightly tacky film with excellent UV resistance, is easily removed with an alkaline cleaner and pressure washer, can be tinted to custom colors, and can be thinned with water. In the Cortec Product Consultation Guide it is rated 4 (outside, uncovered storage) on carbon steel, stainless steel, cast iron, aluminum alloys, galvanized steel, copper, brass and solder, the same rating as the solvent-based VpCI-368 and oil-based VpCI-369. Switching from a solvent coating to VpCI-389 takes the VOC load off an air permit: 0.1 lb/gal against more than 3 lb/gal for a conventional solvent-borne coating.

Typical applications

• Harsh, outdoor, unsheltered environments
• Multi-metal protection
• Temporary equipment and component protection
• Unpainted machined surfaces on finished equipment awaiting shipment or installation
• Equipment, castings and fabrications stored in open yards
• Export and transit protection for machinery, including painted surfaces
• Pipe, valves, flanges and structural steel between fabrication and erection
• Preservation of idle or mothballed equipment

How to apply VpCI-389

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-389 may be thinned with water up to 10 % by volume to adjust viscosity; ask Cortec or us before going further.
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.
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 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 is fine) no longer than 100 ft.
5. Film build. Apply 2.7 to 5.4 mils wet to leave 1.0 to 2.0 mils (25 to 50 µm) dry. Theoretical coverage is 595 sq ft per gallon at 1.0 mil DFT.
6. Drying. Dry to touch in 10 to 60 minutes and dry to handle in 20 to 60 minutes at ambient conditions; force-dry 15 to 20 minutes at 150 °F (65 °C) if the line needs it. Full cure takes 3 to 7 days. There is no recoat window because a second coat is not part of the system.
7. Cleanup. Clean tools with water while the coating is wet; once dry use butyl cellosolve or MIBK, following the solvent manufacturer’s safety directions.
8. Removal. For a film at the recommended 1.0 to 2.0 mil 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.
9. Storage. Keep the container sealed, do not let it freeze, and do not store above 100 °F (38 °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-389 is one of Cortec’s four top-selling temporary coatings alongside VpCI-368 (solvent-based, waxy), VpCI-369 (oil-based, self-healing) and VpCI-391, the water-based sibling that dries non-tacky and can be welded through. Pick 389 when you want the waxy, UV-stable outdoor film without solvent VOCs; pick 391 when parts will be handled, machined or welded before the coating comes off. VpCI-389 D is the same coating pre-diluted for spray, and EcoSpray VpCI-389 puts it in a 16 oz pump bottle for touch-up. The remover is VpCI-414. For rusted steel that needs to be sound before coating, start with VpCI-422 or VpCI-426 rust remover, or convert the rust in place with CorrVerter. Browse the full Cortec VpCI line.

Field notes

A St. Paul, Minnesota plastics molder had machine cooling chambers nearly closed off by rust. The chambers were cleared by circulating an 8% descaler for about three hours, corroded parts dipped in VpCI-422 and VpCI-423 for eight hours and rinsed, then sprayed with EcoSpray VpCI-389 for a waxy protective film that also eased reinsertion. (Cortec Case History #050)

A grain and fertilizer terminal operator on the Ohio River found loaders moving deicing salt and fertilizer looked ten years old after one year and were replaced every 2 to 3 years. Once a year each loader is power-washed with an alkaline cleaner to neutralize the salts, dried and oversprayed with VpCI-391 everywhere except the glass. The program has run a decade with no permits needed for the low-VOC coating. (Cortec Case History #735)

A Southeastern U.S. construction-equipment maker had loaders and skid steers sitting outside 6 to 12 months around dealer shipment, and the old oily rust preventive stayed sticky, collected dirt and could wash off. After testing VpCI-391 on fiberglass cabs and paint from about 2017, it goes on unpainted parts, bolt heads, hydraulic boxes, rims and tubing; no appearance complaints, and most dealers leave it on. (Cortec Case History #776)

Specifications

Salt spray (ASTM B117)	600 hours
Humidity (ASTM D1748)	1,000 hours
VOC (ASTM D3960)	0.1 lbs/gal (12 g/L)
Coverage	595 sq.ft/gal @ 1.0 mil DFT
Recommended DFT	1.0–2.0 mils (25–50 µm)
Film	Dry, slightly tacky
Removal	Use a VpCI-41x series alkaline cleaner/degreaser
UV	Excellent UV resistance; custom color matching available
Type	Water-based removable (temporary) coating
Volume solids	37.1%
Recommended WFT	2.7–5.4 mils (67.5–135 µm)
Viscosity	5,500–10,000 cP
Weight per gallon	8.32 lb (1.00 kg/L)
Flash point	201.2 °F (94 °C)
Dilution	Water, up to 10% by volume to adjust viscosity
Dry to touch / dry to handle	10–60 min / 20–60 min
Force dry	15–20 min at 150 °F (65 °C)
Full cure	3–7 days
Recoat	N/A
Surface preparation	Clean and contaminant-free; NACE No. 3 / SSPC-SP6 on structural steel
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)
Size	5 Gallon Pail
Shipping weight	44.5 lb (20.2 kg)
Availability	In stock
Cortec product number	12303555

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.