For: Dealers and commercial buyers ordering racks, frames, benches and storage, and anyone who may later have to argue a finish warranty claim.
The decision: What the manufacturer must state in writing about the finish before the order, so a later chip, peel or rust spot can be judged against a document instead of an opinion.
60-second answer: “Powder coated” names an application method, not a finish system. Before ordering, get in writing the powder product and resin family, the pretreatment sequence, the film thickness range and how it is measured, the cure schedule from the powder manufacturer’s technical data sheet and how the line verifies it, test reports that name the method and the test conditions, and the finish warranty terms. A salt spray result is a laboratory comparison, not a prediction of service life.
What the finish specification decides
The finish on a rack or frame is what members see first, and it takes chalk, sweat, cleaning chemicals and plate contact every day. When it chips, peels or rusts, the question is whether it met what was promised, and a purchase order that says “black powder coat” promises nothing that can be checked.
Specifiers outside fitness make the same point. The Construction Specifier’s review of powder and liquid coatings says that “powder coating is an application method, not a specific product,” and that a common mistake is to specify only “powder coating.” Two quotes that both say powder coated can describe different resins, pretreatments, film builds and process control.
Records to pull
- Finish complaints, photos and warranty claims for the frames already in service, with model, purchase date and location of each.
- The environment for each area of the new order: interior strength floor, pool-adjacent room, daylight through glazing, or covered or open outdoor space.
- The cleaning products used on frames, with dilution and contact time, and the finish and warranty sections of the current supplier’s documentation.
The finish system: resin, pretreatment and film thickness
The resin family should match the environment. Arkema, which supplies resins to powder makers, says polyester powders are widely selected for exterior and outdoor applications, while hybrid epoxy-polyester systems are typically selected for interior applications where UV exposure is limited. Ask which powder is used, by manufacturer and product name, and whether that powder’s manufacturer rates it for the conditions you described.
Pretreatment cannot be inspected on a finished frame, so it has to be described in writing. IGP Powder Coatings’ technical information says surfaces must be pretreated to improve corrosion resistance and adhesion, and that contamination on the metal impairs adhesion. It describes iron phosphating as sufficient for powder-coated parts in unstressed areas but generally not for weathering or permanent moisture, and zinc phosphating as achieving the best corrosion resistance of paint coatings on steel. It also says a protection system should be chosen for the desired duration of protection and the environmental conditions. Ask the manufacturer to list its cleaning, rinsing and conversion-coating stages and chemistry, and how they fit the environments on your order.
Film thickness is one of the few finish properties a buyer can check after delivery. ASTM D7091 describes the use of magnetic and eddy current gages for nondestructive dry film thickness measurement on ferrous metals. Ask for the specified range, the measurement method and where on the part readings are taken. A powder’s data sheet may give a recommended range, as IGP’s data sheet for one of its industrial powders does, so ask that the equipment maker’s range be consistent with the data sheet for the powder it names.
Cure: the schedule comes from the data sheet
Thermoset powder does not dry; it cures. Arkema describes the coated part being heated so the powder melts, flows and chemically crosslinks into a continuous film. The time and temperature needed are set by the powder manufacturer for each product, not by the equipment maker and not by FEX. IGP’s data sheet for one of its industrial powders, for example, gives its curing conditions as a table of temperature and time combinations. Columbia Coatings, a powder coating supplier, says its cure schedules are listed as part metal temperature unless otherwise stated, and appear on both the powder label and the technical data sheet.
That gives a buyer two questions: which powder product and data sheet apply to this order, and how does the coating line confirm that parts, including the heaviest sections, reach that schedule, and what record does it keep? An oven set point alone does not answer the second when the schedule is stated as part metal temperature.
The same IGP data sheet reports film tests on 0.5 mm steel panels at a stated cure, and reports salt spray results separately for iron-phosphated and zinc-phosphated panels. Those results describe the powder on a prepared test panel. They are not results for your rack unless the equipment manufacturer tests its own production parts.
Test reports: what B117, D3359 and D3363 show
Suppliers often answer finish questions with a test name. Each test has a defined scope, and each leaves something out.
| Test | What its scope covers | What it does not establish | Request with the report |
|---|---|---|---|
| ASTM B117 (current edition B117-26a) | Operating a salt spray (fog) apparatus | It does not prescribe the specimen, the exposure period or how to interpret results; ASTM says prediction of performance in natural environments has seldom been correlated with salt spray results used as stand-alone data | Exposure hours, specimen and pretreatment, any scribe, and the pass criteria applied |
| ASTM D3359-23 | Rating adhesion of coating films on metal with tape applied over cuts; Method A mainly for coatings over 125 µm (5 mils), Method B for coatings under 125 µm | It does not distinguish between higher levels of adhesion, and in multicoat systems a failure between coats does not measure adhesion to the substrate | Method used, measured film thickness, rating, and whether samples were production parts |
| ASTM D3363-22 | Film hardness of an organic coating on metal, using pencil leads of known hardness | Results can vary between laboratories with different pencils and substrates, and ASTM advises caution when comparing coatings of similar hardness | Pencil grade achieved, substrate and testing laboratory |
| ASTM D7091-22 | Nondestructive dry film thickness measurement with magnetic and eddy current gages | Thickness only, not adhesion, cure or corrosion resistance | Readings by location, including edges and welds, with the gage recorded |
A test report supports a claim only if it names the method and edition, the specimen and its pretreatment, the conditions, and the result against a stated criterion. “Passed salt spray” without hours, specimen and criteria supports nothing. Data sheets may cite ISO methods instead: IGP’s uses ISO 2409 for cross-cut adhesion and ISO 9227 for neutral salt spray, and ASTM says D3359 is similar in content to ISO 2409 but not technically equivalent, so ask for the method actually run.
What to request in writing, triggers and red flags
| Item | Request in writing | Acceptable answer | Resolve before ordering |
|---|---|---|---|
| Finish system | Powder manufacturer, product name and resin family | Named product with its data sheet | “Standard black powder coat” |
| Environment | Confirmation the powder suits the conditions you described | Written confirmation that refers to the data sheet | One house finish for every room, with no answer on conditions |
| Pretreatment | Cleaning and conversion-coating stages and chemistry | Stages listed in sequence | “Cleaned prior to coating” |
| Film thickness | Specified range, method and measurement locations | Range consistent with the data sheet, edges and welds included | No range stated |
| Cure | Data-sheet cure schedule and how part temperature is verified | Schedule cited from the data sheet, with a description of the verification record | Oven set point only |
| Test reports | Method and edition, specimen, pretreatment, conditions, criteria and results | Complete reports, stating whether panels or production parts were tested | Test names with no reports |
| Color and batch | How replacement parts will be matched for the life of the order | Named color reference and powder product | No color reference |
| Repair | Approved touch-up product and replacement parts in the same finish | Named product and stocked parts | Nothing supplied |
| Warranty | Finish failures covered, exclusions for environment and cleaning chemicals, and the remedy | Defined failures and remedy in writing | Finish excluded or undefined |
Compare the finish warranty alongside the rest of the terms using the commercial warranty comparison, and check the cleaning-chemical exclusions against the products your staff use with matching cleaning products to surfaces and contact time.
Review triggers you set
Decide from your own records what reopens the finish specification: for example, the first finish complaint on a new model, contact-point damage on several units, a change of cleaning products, an order for a new environment such as a pool room, or a top-up order that must match existing frames.
Red flags
- Salt spray hours presented as years of service.
- Test-panel results presented as results for the equipment.
- A finish warranty that excludes “cosmetic” damage without defining it, or cleaning-chemical exclusions your staff cannot comply with.
What to do this week
- Pull finish complaints, photos and claims for current frames, and record the cleaning products used on them.
- Send each quoted manufacturer the request list above, with the environment for each area of the order.
- Ask for the powder data sheet and complete test reports, and check that each report names its method, specimen and criteria.
- Write the film thickness range, measurement locations and finish warranty terms into the purchase order.
- Plan the delivery inspection: photograph contact points and record any film thickness readings at edges and welds in the acceptance file.
Continue with FEX
- Installation closeout: acceptance, punch list and final invoice
- Rack attachment compatibility before ordering
- Refurbished equipment grading
FEX editorial guidance: the request list, review triggers and red flags are FEX analysis. Cure schedules, film thickness ranges and pretreatment requirements come from the powder manufacturer’s technical data sheet and the equipment manufacturer’s process; FEX does not set them. This is not engineering advice; for a disputed finish failure, ask the manufacturer for its test evidence and consider an independent coatings inspector.
Source notes
- The Construction Specifier: VOCs… and Beyond: Powder and liquid coatings reviewed (April 28, 2014) — Powder coating as an application method, not a product.
- Arkema: Powder coatings (accessed October 2026) — Resin families by environment and the cure process.
- IGP Powder Coatings: TI 100 Pretreatment of metals (v1) — Pretreatment, iron versus zinc phosphating, and matching protection to environment.
- IGP Powder Coatings: Technical data sheet, IGP-HWFindustry 7909A-A0 (accessed October 2026) — Curing conditions, film thickness, ISO test methods, test panels and salt spray results by pretreatment.
- Columbia Coatings: General Powder Coating Instructions (accessed October 2026) — Cure schedules stated as part metal temperature on the label and data sheet.
- ASTM: B117-26a Standard Practice for Operating Salt Spray (Fog) Apparatus (updated September 22, 2026) — Scope and limits on correlation with natural environments.
- ASTM: D3359-23 Standard Test Methods for Rating Adhesion by Tape Test — Methods A and B, limits, and relationship to ISO 2409.
- ASTM: D3363-22 Standard Test Method for Film Hardness by Pencil Test — Scope and limitations.
- ASTM: D7091-22 Nondestructive Measurement of Dry Film Thickness — Scope.
Editorial update, October 8, 2026: Removed the unsourced nine-month failure narrative and under-cure claims, plus EPA transfer-efficiency, VOC and powder-recycling figures that did not bear on the buying decision. Verified the scope of ASTM B117, D3359, D3363 and D7091 on ASTM’s pages, stated that cure schedules come from the powder manufacturer’s data sheet, and reframed the piece as a written finish specification request.
