Every spare-parts crib has a shelf of steel that has been there longer than anyone can remember. When a customer finally needs one of those parts, it comes down covered in surface rust, and the order that should have shipped this afternoon goes to the blast room or out the door to a plating shop for cleaning. The part is fine. The three days it takes to make it look fine are the problem.
A Racine, Wisconsin gear and drivetrain manufacturer fixed this with two dip tanks and a drying rack, and then fixed the cause by changing how the stock was packaged. Cortec Case History #489 (2014) is the shortest description of a clean, protect and ship workflow we know of, and it transfers directly to any Midwest plant with a shelf of aging spares.
The problem: blasting parts that were never damaged
The plant shipped a large number of service parts that had been in stock for several years. Rust was cosmetic, but a customer paying for a gear does not want to receive an orange one, so every rusty part was either media blasted in-house or sent to an outside vendor for cleaning. Either route took days. The goal the plant set was simple: pull the part, clean it, protect it and ship it on the same day it was ordered.
What they did: a 20-minute soak and a dip
Parts pulled for the day’s shipments were inspected. Anything showing corrosion went through three steps:
- Submerge in VpCI-422, an organic biobased rust remover, at full concentrate for up to 20 minutes.
- Rinse quickly with water.
- Immediately submerge in VpCI-415, an alkaline cleaner that neutralizes the rust remover and leaves a corrosion-inhibiting film good for months of indoor storage.
The parts were then air dried and packed. Cortec’s before-and-after photographs show gears and machined housings going from uniformly rusted to bare, bright steel with no change to the surface finish. The plant reported that the sequence let it ship critical spares the same day, and that the time and money saved on outside cleaning paid for the tanks quickly.
| Step | Product | Concentration | Time |
|---|---|---|---|
| De-rust | VpCI-422 | As supplied | Up to 20 minutes |
| Rinse | Water | Quick | |
| Neutralize and protect | VpCI-415 | 5 to 10 percent (data sheet) | Dip, then air dry |
Why VpCI-422 rather than a mineral acid: it passes hydrogen embrittlement testing, which matters on hardened gears and fasteners; it does not attack the base metal, most paints, rubber or skin; and it is 92 percent biobased and non-flammable, so it can sit in an open tank in the shipping department. It is approved for carbon steel, stainless, cast iron, galvanized, copper and brass. It is not rated for aluminum, where VpCI-426 is the correct remover.
Why the immediate dip in VpCI-415: freshly de-rusted steel flash rusts within minutes in a humid shop. The alkaline cleaner stops the reaction and leaves a multi-metal inhibitor film, and its near-neutral pH makes it the gentlest of Cortec’s heavy-duty cleaners on mixed-metal assemblies.
What they did next: stop the rust before it starts
The de-rust line solved the shipping delay, but it was still a daily task. The plant’s second step was to move its stock into VpCI-126 bags with a BioPad emitter inside. The bag is a vapor-phase corrosion inhibiting film rated for up to five years of protection; the BioPad adds a concentrated VpCI source for the enclosed air. Once the stock was packed that way, the daily rust removal stopped. The 2014 case describes that as the end state: the tanks stayed for the occasional part that had been on the shelf before the program, and new stock went into bags.
How to do this in your plant
- Set up three stations near shipping. A tank of VpCI-422 large enough to submerge your biggest common spare, a water rinse tank, and a tank of VpCI-415 at 5 to 10 percent. Fit the 422 tank with a screen or a pump and filter so metal fines do not build up. Our VpCI product selection guide lists which remover and cleaner suit each metal.
- Soak, rinse, dip, dry. Twenty minutes handles light to moderate rust; heavy scale may need a second soak or agitation. Parts must go from rinse to the 415 tank without waiting.
- Do not blast unless you have to. If a part is pitted or needs a profile for paint, it goes to the blast room. Surface rust on a machined part does not.
- Package new stock as it goes on the shelf. Clean, dry part in a VpCI-126 zip bag, a BioPad cut to size for the volume, press the zip shut. The zip bag can be opened for inspection and resealed. For bulk bins, use VpCI-126 gusseted bags.
- Work the old stock through in batches. Pull a shelf a week, run it through the tanks, bag it. Within a few months the tanks are only for returns and odd finds.
- If the parts also need a wash before shipping, a Build-All or Magido parts washer charged with the same VpCI cleaner does the neutralize step and the degrease in one pass.
Which Cortec products
- VpCI-422, 5-gallon pail: the rust remover in the case; charge a dip tank or a sprayer for in-place work. Not for aluminum.
- VpCI-415, 5-gallon pail: neutralizing cleaner with up to six months of indoor protection; biodegradable and extremely low VOC, with an NSN (6850-01-583-3039) if you sell into defense.
- VpCI-415, 55-gallon drum: for a production dip tank.
- VpCI-126 Blue zip-close bag, 24 by 30 inch: the stock-shelf bag for housings, gears and kits.
- BioPad roll: cut-to-size biobased VpCI emitter, 1 square foot per 15 cubic feet of package.
- BioPad 2 by 3 inch pads: pre-cut for small bags.
All of these are stocked in Elmhurst, Illinois, and a 5-gallon pail of VpCI-422 and VpCI-415 is enough to run a trial on a shelf of your own rusty spares. Contact Solvent Recycling Systems and we will send samples, size the bags and BioPad for your parts, and quote the tanks if you want them.
Sources: Cortec Case History #489 (2014); Cortec product data sheets for VpCI-422, VpCI-415, VpCI-126 and BioPad.
