Water-Based 2K DTM Epoxy Primer — Part B – 1 Gallon (Cortec® VpCI®-395 Part B)

Description

VpCI®-395 Part B is the hardener component of the VpCI-395 two-component water-based epoxy primer. It mixes 4:1 with the white-base Part A and 3.5:1 with the clear base, one gallon of Part B to one container of aluminum, clear or white Part A, to make a kit. Stocked, so a kit can ship as soon as the made-to-order Part A arrives.

Part B has no use on its own; it is bought to complete VpCI-395, the water-based epoxy primer Cortec rates 5 (immersion service) on carbon steel, stainless steel, cast iron, aluminum and galvanized steel in its Product Consultation Guide. The mixed system delivers 1,000 hours of salt spray at 0.2 lb/gal VOC, cleans up with water and can be applied direct to metal on structural steel, tank interiors and splash-zone equipment. Keep a spare gallon on the shelf: a kit with a short or spoiled hardener is a kit that cannot be used, and Part B is stocked while Part A is made to order.

Typical applications

• Hardener for VpCI-395 epoxy primer kits
• Replacement Part B for kits whose hardener has been used or spoiled
• Direct-to-metal primer systems on structural steel
• Immersion service on tank interiors, sumps and splash zones
• Harsh outdoor unsheltered environments under a VpCI-386 topcoat

How to apply VpCI-395

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. On aluminum, galvanized or plated substrates apply VpCI-373 at 0.5 to 1.0 mil first and test adhesion.
2. Mixing. Add 1 part Part B to 4 parts Part A by volume and power-agitate to a uniform consistency with a squirrel-cage or drill mixer. When spraying from a pressure pot allow 15 to 30 minutes of sweat-in time. Pot life is 2 to 3 hours.
3. Dilution. Thin the mixed material with water up to 10 % by volume if needed.
4. Conditions. Apply between 45 and 90 °F (7 to 32 °C) with the surface at least 5 °F (2 °C) above the dew point.
5. 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.
6. Film build. Apply 1.5 to 3.0 mils (37.5 to 75 µm) dry, 3.0 to 6.0 mils wet; theoretical coverage is 779 sq ft per gallon of mixed material at 1.0 mil DFT.
7. Drying and topcoating. Dry to touch in 20 to 30 minutes, dry to handle in 1 to 2 hours; recoat or topcoat between 2 and 72 hours, sanding after that. Full cure takes 3 to 7 days; allow full cure before immersion. Indoors, out of UV, the primer can be left as the finish.
8. Cleanup. Water while wet; butyl cellosolve or MEK once dry.
9. Storage. Keep the container sealed, do not let it freeze and do not store above 100 °F (38 °C). Shelf life is 1 year.
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

Every VpCI-395 kit is one Part A plus this Part B. If a single-component immersion-rated coating suits the job better, VpCI-396 moisture-cure urethane needs no hardener and tolerates marginally prepared steel, at the cost of 3.1 lb/gal VOC. Atmospheric-service alternatives are the water-based acrylics VpCI-386 and VpCI-375. Before priming rusted steel, derust with VpCI-422 or convert the rust with CorrVerter. Browse the full Cortec VpCI line.

Field notes

A Serbian utility’s steel power-line piers in the mountains could not be blasted or water-jetted. Loose rust was wire-brushed, CorrVerter applied at 70 to 80 µm dry film with 10 hours’ drying, then a third-party two-part epoxy mid-coat and polyurethane topcoat at 60 µm each, for a 15-year target life. (Cortec Case History #545)

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)

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)

Watch: Cortec coatings technology

Video by Cortec Corporation.

Specifications

Mix ratio	4:1 by volume for the white base (4 gal Part A to 1 gal Part B); 3.5:1 for the clear base (3.5 gal Part A to 1 gal Part B)
System salt spray (ASTM B117)	1,000 hours
System VOC	0.2 lbs/gal (24 g/L)
System humidity (ASTM D1748)	500 hours
Type	Hardener (Part B) for VpCI-395 two-component water-based epoxy primer
System volume solids	48.6%
System coverage	779 sq.ft/gal mixed @ 1.0 mil DFT
System DFT / WFT	1.5–3.0 mils dry; 3.0–6.0 mils wet
Sweat-in / pot life	15–30 min in a pressure pot; 2–3 hr pot life
System dry times	Dry to touch 20–30 min; dry to handle 1–2 hr; recoat from dry to touch up to 72 hr; full cure 3–7 days
Consultation guide rating (VpCI-395)	5 – immersion service on carbon steel, stainless steel, cast iron, aluminum, galvanized steel
Storage	Original packaging, indoors, out of direct sunlight, 40–100 °F (4–38 °C); protect from freezing; shelf life 1 year
Minimum order quantity	4
Size	1 Gallon
Shipping weight	9.8 lb (4.45 kg)
Availability	In stock
Cortec product number	12401105

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.