Wooting 80HE black zinc case - Rare blistering issue

We’ve received reports on a rare issue with the coating on the Wooting 80HE black zinc case. In a small number of cases (less than 1%) the coating can blister and peel off over time. After digging into the reports, one common thread was that the problem occurs where the user tends to rest their fingers/hands on the case. This led us to believe that the problem occurs when the coating is exposed to the natural oils and sweat from a person's hands. Since this issue only affects a tiny percentage of users, it is likely that the individual's unique composition of that oil and sweat makes a significant impact. This is supported by the likelihood that if a customer experiences this with one case, that they are likely to experience the same thing with a replacement, even if it's a different manufacturing batch.

We’ve since managed to replicate the problem, confirmed the cause, and are now working on an improved version of the black zinc case for people who experience the coating issue. If you already own one or are planning to get one, don’t worry, we’ve got options for you. You’ll be able to choose how we help you out, and we’ll make sure it’s resolved in a way that works for you.

This blog shines a light on how we got to where we are, how we handle defects within and out of warranty generally, and how we're using this knowledge to improve our products in the future.

You can also watch this video of Calder explaining the situation:

How we tested the 80HE black zinc case

Before releasing the Wooting 80HE black zinc case, we ran a series of tests, all of which it passed with flying colours:

#1 Salt spray test

As the name suggests, a salty liquid is sprayed onto the keyboard and left for 48 or 72 hours (depending on the requirement) to observe how the coating reacts to salt exposure.

The Raw Zinc case had trouble going through this test until we applied a UV coating on the case.

#2 Acidity test

There are a lot of different substances your keyboard case could come in contact with and many of them are acidic, like Coca Cola. During this test we put many different substances your keyboard might be exposed to on the case. This includes Coca Cola, vegetable oil, hand lotion, tea and more. We choose products that represent the broadest range of everyday chemical interactions. We then look if the case stains or deteriorates.

#3 Ball drop test

The ball drop test confronts the case with a ball that’s dropped through a tube onto the case. If the case dents or affects the coating in any way it fails the test.

#4 Abrasion test

You’d be surprised by how often people gently stroke and pet their Wooting keyboard, and it would be a shame if the coating is affected by your affection. That’s why we run an ‘abrasion test’ where a machine rubs the case for a certain amount of time. The coating should not get rubbed off or get polished or it will fail the test.

#5 Alcohol test

Alcohol is a very strong chemical and is often used for cleaning. So if you’re using an alcohol wipe or liquid imbued with alcohol we want to make sure it doesn’t remove the coating or damage the case.

#6 Adhesion test

Then there’s the adhesion test. When a case has a coating applied to it there’s a certain level of stickiness between the coating and the case material. During this test, we put tape on the case and rip it off to see if the coating stays on the case. Adhesion is important because it prevents ‘chipping’.

#7 Pencil hardness test

We’ve added this test to the procedure because our (v1) white zinc case would get gray scratch marks after being scratched by a sharp metal object. During this test we use a range of pencils with different levels of hardness and scratch the surface to see if it leaves any scratches or marks.

After the black zinc case passed all these tests we brought it onto the market expecting no issues.

Black zinc case issue

After releasing the Wooting 80HE things were going great, until we got that first ticket where the coating peeled off: patient zero. What?! How? Why?

“It must be a quality control issue” - Calder

The black zinc case is produced as follows:

1. A zinc alloy is dye cast into the right shape.
2. The inside of the case is ‘cut out’ through CNCing.
3. The case is then polished.
4. A nano black e-coating is applied.
5. The coating is hardened in an oven.

After these processes, the black zinc case is done, ready to be packaged and shipped out.

Our first thought was that there must be a quality control issue in one of these steps, and it would probably be a whole batch that had the same defect. But after investigating the process we didn’t find any obvious gaps in the quality control process.

Replicate the issue, find the solution

The next step on our way to solving this issue was to try and replicate it.

Coating adhesion testing

To see if it’s a problem with the adhesion of the coating, we scratched off squares of the coating in a checkers pattern, applied tape to the squares that had the coating, and removed the tape to see if the coating would come off with the tape. We did this for different production batches to find out if the issue only occurred in certain batches.

Sadly, we didn’t manage to replicate the issue during this phase.

Improved polishing and coating process

The polishing process affects the adhesion of the coating, so we checked if we could find our issue here. The thing with polishing is that it’s very important to immediately coat the case after it’s polished. The more time a polished case rests, the more the outer layer oxidises, which in turn makes for a worse surface to apply the coating to.

So we shortened the time between polishing and applying the coating and did the checkers pattern test again, and improved the adhesion of the coating on the polished metal surface.

Put the improved case to the test

We then sent one of those improved cases to that same customer that had the coating peel off (thanks for being our guinea pig). Although it took a bit longer this time, the customer ran into the same issue where the coating peeled off.

Two new occurrences

By now there were 2 other customers that had the same issue, meaning it happened in less than 0.4% of all cases. We knew we had to go at it more aggressively, and do more tests to find the root of the issue.

At this point we decided to not ship any replacement cases to people who ran into the coating issue, since the issue would most likely occur again.

Rubbing test

We did a rubbing test on the exact spots where the issue occurred with customers, but didn’t find the problem there.

Sweat test

Then we did a sweat test, where we simply applied artificial sweat to the spots where the peeling off occurred, and this time we were able to replicate the issue. So we dialed up the sweat test, using different, more acidic solutions for the artificial sweat.

We also added these tests to the Wooting 60HE v2 case testing procedure. *We posted a video on that you can watch here: *https://www.youtube.com/watch?v=5vBXhzRdeQ4

Now that we found the perpetrator…

We needed to find out: is the coating reacting to the sweat? Or is it the case material?

So we visited the case factory, as well as the coating factory and concluded that it was indeed the coating that was reacting to the sweat.

But why is the coating not reacting to everyone's sweat?

Every person is unique, and so is their sweat! Your sweat’s composition is affected by a lot of factors, like your location (inside or outside), what you’re doing (running, baking in the sun) and your diet.

To find out more we looked at the correlation between the artificial sweat’s pH value, and the effect it has on the case coating.

Fun fact: pH measures the ratio of hydrogen (H⁺) to hydroxide (OH⁻) ions in a solution. The lower the pH, the more free hydrogen is floating around, and the more acidic your sweat is.

The acidic sweat test

To see if the coating reacted differently to different pH values in sweat, we tested two types of artificial sweat, one with a pH value of 4.5 and one with a pH value of 8.5.

Human sweat has a pH value typically between 4.7 and 5.7,¹ and environmental changes or factors like if a person has exercised recently (or a recent intense ranked match?) can change sweat composition.²

The test confirmed what we already expected: a lower pH level accelerates case coating deterioration.

Now that we understand the issue we’re dealing with, we’re figuring out where to set the standard when it comes to our keyboard’s case coating resilience against sweat.

Extent of the issue

Five months after the official Wooting 80HE launch, we were looking at about 2 or 3 cases that had coating issues, after which we started monitoring the amount of incoming tickets related to this issue closely. After about 6 or 7 months we saw a significant increase, but it still happened in less than 0.4% of all cases. Over the last few months, the number of reports we've received has stabilized at just under 1% of customers.

While this occurs to a manageably small number of people, to those who do experience it: a blemish like that on their premium keyboard case is a blemish on Wooting as a company. We have to do right by them.

What does this mean for (future) black zinc case owners?

If you have a Wooting 80HE black zinc case, or you’re planning on buying one, don’t panic! We plan to create a black zinc case with an alternative coating method and will make that available for people who experience this, which should take 6 months to be ready. In the meantime, if you run into this issue with your black zinc case, please contact customer support, once we’ve validated the issue we have a range of solutions you can choose from.

We will keep you updated on any progress we make regarding the black zinc case for the Wooting 80HE

We’re committed to our customers and creating sustainable and reliable products that stand the test of time.

<3

Tim

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Refrences:

1. Baker, Lindsay B., and Anthony S. Wolfe. “Physiological Mechanisms Determining Eccrine Sweat Composition.” European Journal of Applied Physiology, vol. 120, no. 4, 2020, pp. 719–752. https://doi.org/10.1007/s00421-020-04323-7

2. Baker, Lindsay B. “Physiology of Sweat Gland Function: The Roles of Sweating and Sweat Composition in Human Health.” Temperature (Austin), vol. 6, no. 3, 2019, pp. 211–259. https://doi.org/10.1080/23328940.2019.1632145. PubMed Central, PMC6773238.