Most powder-coating advice is written for the person who holds the spray gun. This one is written for the person who signs the purchase order, checks the delivery, and hears about it when a batch fails.

I manage purchasing for a 165-person metal fabrication company. I order powder coatings, liquid primers, masking supplies and finishing consumables, roughly $450,000 a year across seven active vendors. I have never operated a coating line. What I have learned is how to write a specification that prevents failures, and how to prove what went wrong when a failure still happens.

Use this checklist when you buy powder coating from a new supplier. If the supplier is already established, steps 3, 4 and 5 are still worth reviewing, because those are the ones I ignored for too long.

Step 1. Confirm the actual manufacturer, not just the logo

The coating trade is full of brokers and repackagers who say they supply AkzoNobel products. Some are legitimate distributors; others buy a drum, repackage it, and borrow the name. AkzoNobel does make a broad portfolio of powder coatings under the Interpon brand, but the word AkzoNobel on a quote tells you whose product is supposed to be in the box, not who actually put it there.

Ask the seller to confirm in writing on the order:

  • brand and product line, for example Interpon for AkzoNobel powder coatings;
  • the legal manufacturer name. In the United States this is often AkzoNobel Coatings Inc.; in other regions it will be a different named legal entity;
  • product code, batch number, and the technical data sheet number, not just a color name.

This is not paperwork for its own sake. In 2022 I accepted a quote that was about $900 cheaper because I liked the salesperson. The powder came from a repackager who could not supply a traceable batch certificate or a proper invoice. Our finance team rejected the invoice, and our production team had already used part of the material. The rework and wasted labor cost us roughly $4,600. I still remember that number whenever someone tells me that technical details are only for chemists.

Step 2. Buy a product code, not a color description

Powder coating is not liquid paint without the solvent. It is a factory-blended mix of resin, curing agent, pigments and fillers. The same gray color can be an epoxy for corrosion protection or a polyester for exterior durability. If the order says gray RAL 7035 and nothing else, you are leaving the most important decisions to whoever happens to fill the order.

A product code tells the applicator what the coating is and how it should cure. Our internal work orders now list the manufacturer, the product code, the batch number and the required film thickness. If the code is missing, we stop and ask.

The strangest lesson came from a tote with no label at all. Someone put it into inventory as untitled paint. No product name, no code, no batch number. It looked like ordinary industrial gray, so a team treated it as ordinary industrial gray and coated 140 brackets. The finish cured with an uneven texture and poor adhesion, and all 140 had to be stripped. The powder was not necessarily bad; the problem was that nobody could verify what it was. Untitled paint should be a quarantine signal, not a production experiment.

Step 3. Put dry film thickness into the order

Powder coatings are specified by dry film thickness, usually measured in microns. Too thin means the coating lacks protection. Too thick costs extra powder and can cause surface problems such as orange peel or poor flexibility. If you do not write a thickness range into the purchase order, you have no way to judge the delivery later.

Ask the product data sheet for the recommended range. For many architectural polyester powder coatings, 60 to 120 microns is typical, and we order 70 to 90 for most parts. This range also helps an applicator quote the work accurately. Thickness is not a theoretical matter. On a line doing several hundred square meters a week, a coating that is consistently 20 microns above target consumes substantially more powder. That difference shows up either in the quoted price or in rework time. Decide where you want it.

Step 4. Make a powder coating thickness gauge part of incoming inspection

If you cannot measure thickness, you do not have a specification; you have a wish. A powder coating thickness gauge is the tool that turns the thickness range into an enforceable term.

For steel substrates, use a magnetic induction gauge. For aluminum, use an eddy current gauge. Dual-function gauges handle both. The gauge does not have to be an expensive laboratory instrument, but it does need to be checked before use. ASTM D7091 describes the common practice of verifying gauges on known reference standards. Our QC team checks the gauge at zero and at a known shim value each day.

The gauge caught our most expensive potential error in Q3 2024. A new supplier delivered parts that looked perfect. Our readings showed an average of 45 microns where we had ordered 60 to 80. Without numbers, the supplier could reasonably argue that the coating was fine and that we had changed our mind after delivery. With the log, there was little to discuss, and they agreed to recoat the batch.

One more lesson from our floor: if a gauge is dropped, verify it before the next use. Ours took a fall from a workbench and measured roughly 20 microns high afterward. Everything we accepted that day was thinner than we thought. A gauge that has never been verified is a decoration.

Step 5. Answer the acetone question, then verify cure

People often search does acetone remove powder coating. The first useful answer for a buyer is this: if the powder coating is fully cured, no. Acetone will not dissolve or strip it, though heavy rubbing may dull the surface. If the powder coating is under-cured or was never cured properly, then yes, acetone can soften it and wipe it off.

That distinction matters during incoming inspection. A batch of powder coated parts can look perfectly normal and still be under-cured. The film may be hard to the touch but weaker than it should be because the curing window was missed. An acetone rub test is a quick way to catch this before parts go out the door.

Here is a simplified version of the solvent rub approach similar to ASTM D5402:

  1. Use a test panel from the same production run, not a customer part, if possible.
  2. Wait until the panel has cooled to room temperature.
  3. Wet a clean white cotton cloth with acetone.
  4. Rub one small area back and forth with moderate pressure. Use the number of double rubs recommended in the coating specification, often around 25.
  5. Check the cloth. If color transfers heavily or the coating starts to soften and uncover, cure is probably incomplete.

This is a rapid signal, not a full quality test. The product data sheet gives the proper cure window in temperature and time, and your coating supplier's technical service can tell you what additional checks make sense. For harsh-environment parts, rely on the full set of recommended tests, not just one solvent wipe.

Also, do not treat acetone as a stripping agent for fully cured powder coating. On a properly cured film, acetone will not work the way paint stripper works, and soaking parts in acetone creates an unnecessary vapor hazard. If you need to remove a cured coating, use the intended removal route: chemical stripping, thermal stripping, or abrasive blasting, depending on the substrate.

Step 6. Log the readings and close the loop with the supplier

The final step of a good powder coating purchase is writing the result down. For every delivery, keep a simple record:

  • date and purchase order number;
  • product code and batch number;
  • dry film thickness readings from the first parts checked;
  • cure check result;
  • gauge verification record.

This list is your evidence. Since we started sending a one-page summary to our distributor, we get faster answers. A complaint without data becomes a debate about blame. With data, it becomes a diagnostic conversation about product, pretreatment or process. Suppliers respond well when they see that you are trying to solve the problem, not just create a dispute.

Last note: small orders still deserve this checklist

This article started from a time when we were still a small shop ordering a $300 trial batch. The distributors who treated that trial seriously are the same suppliers we trust now with much larger programs. Small does not mean unimportant; it means potential. Good suppliers understand that.

Ask the same questions whether the order is $300 or $30,000: who is the actual manufacturer, what is the product code, what thickness range do you need, how are you going to measure it, and how will you verify cure. If a supplier cannot answer those questions for a small order, that is not a sign that you are too small. It is a sign that you should keep looking.