Watch the process first
Cortec put out a one-minute demonstration of the packaging routine we recommend to every shop that ships machined, stamped or remanufactured metal parts. It is short enough to show a packer on the floor, and it covers the three things that decide whether a part arrives clean or arrives orange.
Below is the same routine written out as a checklist, with the products we stock for each step and the places we see it go wrong.
Step 1: Start with a clean, dry part
This is the step the video spends the most time on, and for good reason. Vapor phase corrosion inhibitor (VpCI) packaging protects the surface it can reach. Cutting fluid, chips, fingerprints and existing rust all sit between the inhibitor and the steel, and moisture trapped under a film of coolant will keep working on the part no matter what the bag is made of.
How you get to clean depends on where the part is coming from:
- Fresh off the machine: an aqueous wash, rinse and blow-off dry. A Build-All or Magido aqueous parts washer does this in one cycle, and the parts come out at a temperature that flashes the rinse water off. If the washer detergent carries a corrosion inhibitor, the part also leaves with a short-term flash rust barrier.
- Remanufactured or stored parts with surface rust: the video points to Cortec’s rust removal demonstration for this case. VpCI-422 is a biobased, non-toxic rust and tarnish remover that works by immersion or spray, and the EcoAir VpCI-422 aerosol handles spot work at the bench. Rinse and dry afterwards.
- Oily parts from a supplier: degrease, then dry. Solvent or aqueous, but dry is the point.
Dry means dry. A part packed warm and damp will condense inside the bag on the first cold night in the trailer. If parts are washed in the afternoon and packed the next morning, that is fine. If they are washed and packed within the same ten minutes, give them a blow-off or a few minutes on the rack.
Step 2: Line the box with VpCI-126 film
In the video the parts go into a carton lined with VpCI-126 Blue film. The film is the source of the inhibitor. Once the package is closed, the VpCI molecules vaporize out of the film, fill the air space, and settle onto every exposed metal surface, including bores, threads and the underside of the part where a dip coating never covers evenly. The layer is a few molecules thick. It does not need to be washed off, and the part can go straight into the next operation at the receiving end.
For most shops the practical choices are:
- VpCI-126 zip-close bags in 3.25 x 5, 12 x 12 and 24 x 30 inch stock sizes for individual parts and kits. Zip closure means a packer does not need a heat sealer.
- VpCI-126 tubing cut and heat-sealed to length for odd shapes, or used as a carton liner exactly as shown in the video.
- Gusseted liners and sheeting for pallets and Gaylords, which we quote by size.
Size the film to the part. The inhibitor has to saturate the air inside the package, so a small part in an oversized bag is under-protected and an oversized part pressed hard against a thin bag will puncture it. Cortec publishes a coverage figure for each product, and our VpCI product selection guide walks through the sizing.
Step 3: Add a BioPad if the box has air space
The video adds a BioPad emitter to the carton before closing it. This is the step most shops skip, and it is the cheapest insurance in the routine. A carton full of loose parts has a lot of air volume relative to film surface area, and long transits, humid lanes or ocean containers all pull inhibitor out of the air faster than a liner alone replaces it. A BioPad is a biobased, flexible emitter pad that drops in flat and raises the VpCI concentration in the box. Use one per carton for domestic ground, two for export or anything that sits in a warehouse before use.
For very humid lanes, swap the second pad for a Desicorr VpCI pouch, which absorbs moisture and emits inhibitor from the same unit.
Step 4: Seal it and leave it sealed
Fold the liner over the parts and close the carton, or zip or heat-seal the bag. The package needs to be closed for the vapor to stay saturated. A bag left open on a shelf is not protecting anything, and a carton that is opened at receiving inspection and left open on the dock will start to lose protection within a day or two. If the receiving plant needs to inspect, ask them to reseal the bag or fold the liner back over the parts.
The layer dissipates on its own once the package is open, so there is nothing to wipe off before welding, painting, plating or assembly.
Which products
Everything in the video, stocked in our Illinois warehouse:
- VpCI-126 Blue zip-close bags (three stock sizes) and VpCI-126 tubing
- BioPad emitter pads by the roll, or 2 x 6 and 8 x 8 cut pads
- VpCI-422 rust remover for parts that need the surface brought back first
- Desicorr VpCI pouches for humid and export lanes
- Build-All and Magido aqueous parts washers for step one
Talk to us
We sell both ends of this routine, the washer that gets the part clean and the VpCI packaging that keeps it that way, so we can look at the whole line rather than just the bag. Send us a photo of how your parts ship today and a rough part size, and we will come back with a packaging spec and a per-carton cost. Contact us.
Source: Cortec Corporation published video and product data.
