Got Rust? A Quick Parts Washing Tutorial

If you've been there, then you know how frustrating rusted parts can be. Production stops. Paint doesn't hold. Customers complain. What do you do?

The graphic above shows the linear relationship of volume (%) as it relates to approximate days of protection (rust-free) when using one of our most customer-beloved phosphate-free rust inhibitor products.

In simpler terms, if you charge your washer with 10% soap, you'll likely earn 25 days without rust on your parts, 25% would equate 90 days, and 50% could offer as much as 180 days of rust inhibition. These values are denoted on the graph by dots.

Everything starts with the type of washer you've chosen to use. First, identify if it's a multi-stage conveyor, dip tank, or vertical cabinet. The two points of interest to me are how many stage cycles you have and the volume of each basin, including the rinse cycles if available. ChemStation can accommodate any of these options.

What I learn from this information is how many products you can involve and how to calculate base line dosing.

The second and third steps are to identify the metallurgy (e.g. aluminum vs steel) of the parts you're cleaning and the specific soil that's being removed. Often times an SDS for the soil will help my lab understand what chemistry will work best. Understanding water hardness will also improve results. (e.g. Are you using RO, soft, or city water?)

Our lab will evaluate all of the information provided to custom formulate a product that is optimized for your specific soil(s).

Pending on which style washer you've elected to use, you may want an alkaline specific cleaner designed to attack the soil(s); this is a very traditional and proven strategy. If there is only one stage, you may choose to use a product that combines cleaning and rust inhibition. (Note: The graph above represents the success of a rust inhibitor specific formula. This customer uses a 3-step conveyor to clean a variety of part shapes and sizes, aluminum and steel.)

The pH can be a factor to consider as well. A prototypical first stage alkaline cleaner would generally have a pH value >12 and be considered corrosive on soft metals. In these cases, a surfactant based chemistry would be the way to go. One advantage of our lab is the flexibility to custom design a formula that joins your needs with your budget.

ChemStation offers free consultation and sampling for bulk chemical parts washing. Our local service plans also include titrations (regular verification that the soap % is correct.) Our breadth of partnerships will also extend you a wholesale discount on brand names in equipment (e.g. Dosatron), if you choose to automate the dosing process.

The biggest mistake I see happen is a failure to create and enforce a Preventative Maintenance (PM) plan. Quite simply, you wouldn't take a bath in the same tub of water every night for 5 months and expect to come out as clean as you did on the first go, right? Pending on production or the number of parts being cleaned, an efficient PM plan may be as frequent as every month, or perhaps every quarter. The soil and muck that collects in the washer MUST be removed regularly for optimal performance.

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For some customers, the end game is to paint the parts, which is why they start with adequate rust inhibition. Thereafter, we can certainly help you treat the surface; phosphatizing requires an acid finish that essentially gives the paint a better, more complete overall adhesion.