The Board That Failed in the Rain
March 2023. A control board from one of our marine power units came back covered in green corrosion. Two days later, four more came back. By Friday, our largest customer had pulled 38 units from their fleet. That stung.
I manage procurement for a 140-person electronics manufacturer. Over the past six years, I have tracked every invoice, quote, and rework order in our cost tracking system. We spend about $180,000 a year on materials and services. The conformal coating on a circuit board is a small line item. But that March, it became the most expensive line item in my spreadsheet.
A year earlier, we had switched to a cheaper acrylic conformal coating. It saved us about $1.10 per board. With 4,000 boards a year, that was $4,400 in savings. The coating vendor’s quote looked fine. The field data did not.
The Difference Between Price and Cost
Here’s the thing: I was measuring price, not cost. The old coating was $28 per liter. The replacement was $22 per liter. On paper, that made sense. But the replacement had a higher failure rate in humid environments, and we didn’t catch it until the boards were already in the field.
Our rework cost came to $214 per board. Replacement boards, freight, technician time, and testing. We replaced 87 boards under warranty. That was $18,618. Plus the cost of the extra stock we kept for emergencies. Plus the phone call from our customer’s operations manager, which I cannot put a price on.
The field failure in March 2023 changed how I think about conformal coating. Until then, I was comparing the number on the invoice. After that, I started comparing the number on the annual report.
Had 48 hours to decide whether to pull a second batch and rework it. Normally I would wait for a root-cause report, but our customer’s line was down. I made the call with incomplete information and ate the labor cost. In hindsight, I should have pushed back on the timeline. But with the customer waiting, I did the best I could.
Most buyers focus on per-gallon price and completely miss application cost, rework yield, and warranty exposure. The question everyone asks is “what’s your best price?” The question they should ask is “what’s included in that price?”
Testing Dow Corning 1-2577 Conformal Coating
After the failed batch, I went back to the drawing board with the engineering team. We asked three suppliers for samples. Dow’s industrial coating support services team was the only one that sent actual test boards, a film thickness guide, and a person who answered the phone when we had questions.
We ran humidity, thermal cycling, and solderability tests. The Dow Corning 1-2577 conformal coating was not the cheapest per liter. It was not the most expensive either. It was the one that survived the humidity chamber. According to Dow’s product datasheet, 1-2577 is a one-part silicone conformal coating that cures at room temperature and can be repaired with a soldering iron. That repair ability mattered a lot to us, because we always catch a few wrong components after assembly. Our internal system still lists it under the original dow-corning part number.
Dow Corning 7091 Adhesive Sealant: A Quiet Workhorse
While we were re-qualifying the coating, the assembly team asked me to look at a leak problem in the housings. We had been using an off-the-shelf sealant that sometimes left a strong vinegar smell and caused cure issues in cold weather. We tested Dow Corning 7091 adhesive sealant because it is a neutral-cure, one-part silicone adhesive sealant. The assembly lead liked that it was easy to dispense and did not have that sharp acid smell. I liked that our leak test failure rate dropped from about 6% to under 1%. That saved more in labor than the sealant cost in a year.
The Same Trap With Ship Hull Coatings
Later that year, a customer asked us to help them compare bids for the maintenance of a small barge fleet. I did not know much about marine coatings, so I called the same Dow technical team that helped with the conformal coating. They connected me with their marine specialists and explained the difference between standard antifouling paints and silicone-based foul-release systems. Ship hull coatings are a different world. Same math, different world.
One bid was cheap per liter. Another bid cost more per liter but required fewer coats and had a longer expected dry-dock interval. Over a five-year period, the cheaper bid was about 14% more expensive per square foot once I added surface prep, labor, and downtime. I sat in the meeting and thought: this is the same mistake I made with the conformal coating.
Location Is a Cost, Too
After the coating projects, I started asking better questions before buying anything. When our pharma customer asked us to source a secondary supplier for silicone tubing, the first question that came up was: where is Dragon Pharma located? I was not asking for gossip. The manufacturer’s location drives freight, duties, lead time, and emergency stock requirements. One supplier might quote a lower unit price, but if the product sits on a ship for six weeks and costs an extra $400 in customs paperwork, it is not actually cheaper.
So now my procurement checklist includes three things: unit price, total cost, and location. The first one is easy to find. The second one takes a spreadsheet. The third one takes a question that most buyers forget to ask.
Bottom Line: Teach, Don’t Just Quote
Look, I am not saying cheap coatings are always wrong. I am saying that buying on price alone is a guess. The manufacturer with the lowest quote might have the highest total cost, and the salesperson with the best explanation might save your calendar.
An informed customer asks better questions and makes faster decisions. That is why the industrial coating support services mattered more than the per-liter price. Dow’s team spent time explaining options, not pushing a product. I would rather spend 10 minutes understanding my options than deal with mismatched expectations later.
The board that failed in the rain cost us about $28,000 all together. The replacement coating cost us a little more per liter. The new policy saved us a ton of money in the first year. Price is the number you see before you order. Cost is the number you see after the field report. Use the second one.