A gearbox that leaves the plant with an empty case rusts on the teeth and bearing races above whatever oil film drained off in the first day. The traditional answer is to ship it full of oil, which means paying to fill it, paying to ship the weight, declaring the crate as hazardous freight, and asking the customer to drain and dispose of the oil before commissioning. Or you fog the inside with a solvent-borne preservative and hope the customer flushes it out. Either way the packaging engineer is buying protection for a reducer by the gallon.
There is a cheaper way to do it. Cortec VpCI-329 is an oil-soluble vapor corrosion inhibitor concentrate; a few hundred milliliters in the bottom of the case protects the immersed metal by contact and the rest of the interior by vapor. One French gear manufacturer got up to 48 months of protection at 0.3 percent of case volume and moved its shipments off hazmat. Two more Cortec cases show the same product as a test-oil additive and the sister product VpCI-369 as a five-year exterior preservative that saved an OEM when its supplier stopped delivering.
0.3 percent of case volume, 48 months of protection
Cortec Case History #599 (2018) covers a gear manufacturer near Lyon, France, whose precision speed reducers had to be protected during shipment, storage and between manufacturing operations. Filling the cases with lubricating oil was the incumbent method, and it was costly and shipped as hazardous freight.
The distributor’s recommendation was VpCI-329 at low concentration. It was poured into the bottom of the gearcase lubricant reservoir at only 0.3 percent of the total case volume. The oil-based concentrate works two ways: in contact with the metal it wets, it leaves a tenacious inhibiting film, and its vapor-phase inhibitors migrate through the head space to condense on the gear teeth, shafts and bearings the liquid never touches. For the outside of the reducer, the machined faces and shaft ends were sprayed with CorShield VpCI-369, an oil-based temporary coating that stays as a moisture-displacing wet film.
The manufacturer reported up to 48 months of protection with the reducers kept in operational condition, and adopted VpCI-329 on all its strategic lifting reducers. The savings came from three places: no full oil fill, lower freight because the crate no longer shipped as hazardous, and no drain-and-dispose at the customer.
| Full oil fill | VpCI-329 at 0.3 percent | |
|---|---|---|
| Product per case | Case volume in oil | 0.3 percent of case volume |
| Freight class | Hazardous | Non-hazardous |
| Protection term | Until drained | Up to 48 months |
| At commissioning | Drain and dispose | Fill with service oil; 329 is compatible |
The same concentrate as an emergency test-oil additive
Cortec Case History #770 (2021) is a U.S. engine manufacturer that runs every gas and diesel engine on a test stand before storage and shipment. The custom rust preventative it added to the test oil stopped arriving when the supplier hit an emergency, and the plant was out of material. VpCI-329 had gone through the plant’s rust preventative qualification in 2014 and was already in its system, so samples for viscosity and compatibility checks went out immediately. The plant moved to a custom blend of VpCI-329 at 1:1 with its specified engine oil, added before the test and drained after, with the engine closed off. The residual film is expected to give up to two years of protection in shipping and storage. Production was not suspended.
A five-year exterior preservative held in reserve
Cortec Case History #760 (2022) is the exterior counterpart. A large construction equipment OEM had spent about five years getting VpCI-369 approved as a contingency for the long-term, five-year indoor protection of its service parts, in case the usual supplier could not deliver. In summer 2021 that happened. Because the testing was done, the only open item was tinting VpCI-369 so operators could see coverage, and the OEM was ordering it within about two months. It is sprayed, sometimes dipped, onto every kind of large service part, and can be cut with oil for different spray jobs. The plant has used it since August 2021, finds it sprays easier and is less messy than the old product, and expects the change to be permanent.
How to do this in your plant
- Clean the case and the exterior first. VpCI-329 goes into a dry case; water in the oil emulsifies it. Wash housings and covers in a Build-All or Magido washer and dry before assembly.
- Measure the internal void of the gearcase. At the case’s 0.3 percent, a 100-liter case takes about 300 milliliters of VpCI-329. For a unit that ships with a partial oil charge, dose the oil at 1:19 for short-term, 1:9 for medium-term and 1:4 for long-term layup instead.
- Pour it in, spin the input shaft a few turns to wet the gear train, and close the case. Cap breathers and open ports so the vapor stays inside.
- Coat the exterior. Spray machined faces, shaft ends, couplings and fasteners with CorShield VpCI-369 aerosol at 1 to 3 mils, or brush or dip in bulk VpCI-369 for a run of units. It stays a wet, self-healing film rated for uncovered outdoor storage.
- For bare machined parts going in the crate, dip or spray them in VpCI-329 D, the 1:9 pre-diluted grade, for up to two years indoors or in transit.
- Tag the unit. Note on the shipping papers and the case that it contains VpCI-329 and can be filled with service oil without a flush. The concentrate has no chromates, nitrites or phosphates, so it stays in the oil.
- Check the metals. Both products are rated for carbon and stainless steel, cast iron, aluminum, galvanized, copper, brass and solder; the Cortec compatibility charts cover seals and elastomers.
Which Cortec products
- VpCI-329, 5-gallon pail: the concentrate for gearcases, crankcases and hydraulic reservoirs; 0.3 percent of void in a dry case or 1:19 to 1:4 in oil.
- VpCI-329 D: the same chemistry pre-diluted 1:9 in oil, ready for a dip tank or spray pot; up to two years.
- VpCI-369, 5-gallon pail: wet-film exterior preservative and lubricant for outdoor-rated storage; the OEM’s five-year contingency product in #760.
- CorShield VpCI-369 aerosol: the same film from a can for shaft ends, threads and couplings on individual units.
We stock VpCI-329, VpCI-329 D, VpCI-369 and the CorShield 369 aerosol in Elmhurst, Illinois. If you ship reducers, pumps or engines with a full oil charge or a solvent fog today, contact us for a sample; we can help you work out the dose for your case volumes and set up a trial on a few units before the next export order.
Sources: Cortec Case History #599 (2018), Cortec Case History #770 (2021), Cortec Case History #760 (2022); Cortec product data sheets for VpCI-329, VpCI-329 D and VpCI-369.