Finish and Corrosion Clauses Your RFQ Should Never Leave to Chance

An RFQ that lists dimensions, quantities, and delivery expectations but describes the finish as “zinc plated” is not a complete document. Slide finish and corrosion performance are where buyers and suppliers most often assume they agree — and where the disagreement surfaces after the container arrives.

Why Finish and Corrosion Terms Get Lost in the RFQ

Finish is often treated as a cosmetic afterthought in requests for quotation. A buyer selects a slide type, confirms extension length, chooses soft-close or push-to-open, notes undermount or side-mount, and then adds three words at the bottom: “zinc plated.” Those three words become the entire finish specification — and they will be interpreted differently by every supplier who quotes.

That matters because drawer slides, hinges, and gas springs live in environments that are hard on metal. A cabinet interior holds humidity, kitchen steam, cleaning chemicals, and whatever was spilled last month. The finish on a slide does structural work: it separates steel from moisture, protects cut edges, and keeps ball bearings and raceways moving freely. Treating it as decoration is how buyers end up with rust on a concealed runner a year after installation, or a visible flange whose sheen does not match the last shipment.

Vague language also creates commercial risk. If the RFQ says corrosion resistant and the supplier ships something they consider corrosion resistant, neither party is technically wrong — but the buyer is still holding product they cannot use. Disputes over finish are difficult to resolve because there is no reference point: no agreed test method, no retained sample, no acceptance criteria. The conversation becomes an argument about impressions rather than a check against a written requirement.

The fix is to treat finish and corrosion as specification items with the same weight as dimensions. That means naming the substrate, the coating process, the appearance target, the surfaces that must be covered, the test method used to verify performance, and what happens when a lot fails. It also means attaching that information to the RFQ itself rather than a follow-up email, because the RFQ is the document everyone refers back to when a question surfaces three months later.

Buyers managing drawer slides, hinges, gas springs, and handles should apply the same discipline across each category. The wear points differ, but the principle does not: write down what you expect, in terms a supplier can quote against and a receiving team can check.

Writing a Finish Specification Suppliers Can Quote Against

A workable finish clause answers four questions: what is the base material, how is it coated, what should it look like, and how will conformance be judged.

Start with the substrate. “Steel” is not enough. State whether the component is cold-rolled steel, galvanized, or stainless, because the base material determines which coatings make sense and how cut edges will behave.

Then name the coating process rather than a vague descriptor. Zinc plating, electrophoretic coating, powder coating, and bare stainless each behave differently and cost differently. If you have an approved process, say so; if you are open to alternatives, say that too and ask the supplier to state what they propose.

Appearance deserves its own paragraph. Specify color reference, gloss or sheen target, and whether the finish must be uniform across the whole assembly or only on exposed surfaces. Visible slide flanges, hinge cups, and handles are judged by the end user; concealed runners are judged by the technician. Say which is which, and state how much batch-to-batch color variation is acceptable.

Coverage is where many RFQs fall apart. A coating that covers the flat body of a slide but leaves cut edges, spot welds, rivets, or screw holes bare will corrode first at exactly those points. List the surfaces and features that must be coated, and note any that must stay clear for function — a coated raceway can change how a slide feels.

Include handling and cosmetic acceptance criteria: what counts as a scratch, a tooling mark, a stain, or lubricant residue, and under what lighting inspection will happen. Ambiguity here is expensive at receiving.

Finally, define verification. Salt spray testing to a recognized method, adhesion checks such as a cross-hatch or tape test, and visual inspection against a retained approved sample all belong in the document. Ask vendors how they report results and request a written finish statement per product family. Comparing responses is easier when every furniture hardware supplier answers the same structured questions against the same categories — drawer slides, metal drawer systems, hinges, gas springs, and handles. Retain a signed golden sample so that “acceptable” has a physical definition.

Defining Corrosion Expectations Without Asking for the Impossible

Corrosion requirements fail most often because they are stated as a feeling rather than a test. “Must not rust” is not a specification. A usable requirement names the environment, the test method, the duration, and the pass/fail criterion.

Environment comes first. A slide in a climate-controlled inland kitchen and one in a coastal bathroom with a shower running daily are not the same application, even if the cabinet looks identical on a drawing. Commercial kitchens add steam and aggressive cleaning chemicals; bathroom vanities combine humidity with limited airflow; coastal sites add airborne salt. Write the intended environment into the RFQ so the supplier recommends a coating that suits it rather than defaulting to whatever is standard.

Then separate cosmetic corrosion from functional failure. Light surface oxidation on a concealed flange is annoying; a seized ball bearing raceway is a callback. Decide which one your project cannot tolerate and state it. Many buyers find their real requirement is functional reliability plus no visible corrosion on exposed surfaces, which is a narrower and more useful brief than blanket rust prevention.

Identify the features most likely to corrode first — cut edges, weld spots, rivet points, screw holes, and the bearing tracks themselves — and ask specifically how the proposed finish protects them.

Verification should be agreed, not assumed. Ask which salt spray or humidity method the supplier uses, how long it runs, and what result counts as a pass. A test number without a method and pass criterion means nothing, and comparing two suppliers who test differently is meaningless.

At receiving, build a simple checklist: verify the shipment against the agreed finish statement, compare against the retained sample, check edges and hidden features visually, and spot-check adhesion. Keep records by lot so that if a problem appears months later you can trace it back.

Before the purchase order is issued, ask the supplier directly: which finish do you recommend for this environment, how do you control consistency between batches, and what documentation will accompany the shipment. The answers tell you as much about the supplier as the samples do.