Water-Based Concentrate for Copper & Brass – 55 Gallon Drum (Cortec® VpCI®-316)

Description

VpCI®-316 is a water-based concentrate formulated primarily for copper and brass, built to replace corrosion-inhibiting oils on yellow-metal parts. Diluted 2 to 30 % in water it leaves a very thin, transparent, tack-free film that usually needs no removal before further processing, and it contains no nitrite or phosphate inhibitors. The 55-gallon drum is the size for a production dip tank or a spray stage on a stamping or machining line.

Most water-based rust preventatives are tuned for ferrous metal and are either ineffective or actively unsuitable on copper alloys. VpCI-316 is the Cortec liquid built for brass, bronze and copper, and the brochure notes that it also provides lubrication and cooling during the operation before it dries to its transparent film. Protection runs from about one month to two years or more depending on concentration and storage conditions. In the Cortec Product Consultation Guide it is rated 2 (inside storage) on copper, brass, solder, carbon steel, stainless steel, cast iron, aluminum alloys and galvanized steel, so a mixed-metal line can run it on everything rather than segregating yellow-metal parts. It is not a coating for outdoor exposure.

Typical applications

• Copper and brass protection
• Finely machined parts
• Stamping operations
• Cutting operations
• Replacing corrosion-inhibiting oils
• Bronze and copper-alloy fittings, valve components and bushings held between machining and plating or assembly
• Final dip after aqueous cleaning of yellow-metal parts
• Yellow-metal parts stored indoors before shipment in VpCI-126 film or VpCI-146 paper

How to apply VpCI-316

1. Surface preparation. SSPC-SP-1: free of grease, oil, corrosion, dirt, dust and mill scale. A VpCI-41x cleaner in the wash stage leaves the metal ready for the dip.
2. Dilution. Dilute with deionized water. Hard water is acceptable but may reduce corrosion protection and longevity. Dilute by mass or by volume; the concentrate mixes with light agitation and needs no special equipment. Pick the concentration from the table below.

3. Concentration in water	Indoor protection	Surface after drying
   2–5 %	Up to 1 year	Little to no observable residue
   5–10 %	Up to 2 years	Slight tackiness on some surfaces
   10–20 %	May exceed 2 years	Noticeable tackiness on most surfaces

   Protection lengths assume indoor storage and vary with conditions.

4. Dip. Charge a clean tank with VpCI-316 and water to the target concentration, submerge the part so recesses are wetted, remove and dry before packaging or the next operation.
5. Spray. Once diluted the solution has a viscosity similar to water and runs in a wide range of spray equipment. Spray until every critical surface is coated.
6. Drying. About 15 to 30 minutes at 70 °F and 50 % relative humidity. Drips can be captured and reused. Air movement and heat shorten dry time; keep heated drying at or below 175 °F (80 °C) and avoid so much air that the film cannot form. Dry completely before packaging.
7. Removal. Usually not needed. When it is, rinse with water and follow with a VpCI-41x cleaner/degreaser (VpCI-414, 416 or 418LM) to prevent flash rust.
8. Storage and shelf life. Two years in the original sealed container.

Checking concentration

Concentration (% by volume) = 2.04 × Brix − 0.32 for VpCI-316 in DI water, valid across Cortec’s 0 to 30 % chart. That works out to target readings of about 1.1 °Brix at 2 %, 2.6 at 5 %, 5.1 at 10 % and 10.0 at 20 %. The concentrate has a pH of 7.5 to 8.5 and Cortec’s dilution chart spans only pH 7.0 to 8.0 across the whole 0 to 30 % range, so pH is a weak indicator for this product; use the refractometer as the control and pH as a bath-health check. Hardness, cleaner carry-over, dirt and oil shift refractometer readings, so build a site-specific reference chart with your own water. See the refractometer and pH charts for every Cortec product.

Where it fits in the Cortec line

VpCI-316 is the yellow-metal specialist among Cortec’s water-based rust preventatives. VpCI-377 is the general-purpose multi-metal concentrate with the same dilution ladder, VpCI-379 leaves a paintable dry film, and BioCorr is the ready-to-use biobased option, but BioCorr protects copper and brass for a shorter period than steel (160 to 200 hours humidity against 600 hours on carbon steel). For yellow-metal parts in storage or transit, pair the dip with VpCI-146 multimetal paper or VpCI-126 bags. Shops that clean brass and copper parts in Build-All and Magido aqueous parts washers can run VpCI-316 as the final rinse-stage additive. Browse the full Cortec VpCI line.

Specifications

Dilution	2–30% in water
Protection	1–24 months depending on dilution and conditions
Film	Very thin, transparent, tack-free
Composition	Contains no nitrite or phosphate inhibitors
Appearance	Clear yellow liquid
Non-volatile content	24–29%
pH (concentrate)	7.5–8.5
Density	8.7–8.9 lb/gal
Flash point	>200 °F (93 °C)
Surface preparation	SSPC-SP-1
Application	Dip or spray; dilute with deionized water
Protection by concentration	1:20 in water (about 5%) for 1–6 months; 1:15 (about 6%) for 6–12 months; 1:9 (10%) for up to 24 months
Coating weight	20–60 mg/ft² (0.2–0.6 g/m²) typical
Dry time	15–30 minutes at 70 °F, 50% RH; heated drying not above 175 °F (80 °C)
Concentration check	Vol % = 2.04 × °Brix − 0.32 (DI water); pH window 7.0–8.0
Metals	Copper, brass (<30% Zn), silver and copper-nickel alloys (Cortec data sheet); the Product Consultation Guide also rates it on carbon steel, stainless steel, cast iron, aluminum and galvanized steel
Consultation guide rating	2 – inside storage
Removal	Water rinse followed by a VpCI-41x cleaner
Shelf life	2 years
Size	55 Gallon Drum
Shipping weight	502 lb (228 kg)
Availability	In stock
Cortec product number	12000026

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.