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Keycap Materials

Nov 17, 20222550 VIEWS

Okay, so you’ve decided you want to get some aftermarket keycap sets. What should you look for? Broadly speaking, keycap sets will be split up into three different groups, according to the material they’re made of. In order of abundance, they are:

▪️ ABS

▪️ PBT

▪️ POM

Image Credit: @callmeL Despite this clean delineation of materials, keep in mind that nothing in the real world of manufacturing is this simple. Different manufacturers will use different material blends (the bulk material may be ABS, but there are all sorts of functional additives that will differ), tooling is different and manufactured/maintained to different standards, and quality standards are different. In addition to the materials used to manufacture a keycap set, we must also explore a few different “legending techniques” (how the letters that you see on each keycap get there). We’ll focus primarily on the more premium legending options here, but keep in mind that you might come across others in your searches. If you’re more price sensitive, don’t necessarily write all of those off - they can work just fine and certainly get the job done.

▪️ Doubleshot

▪️ Tripleshot

▪️ Dye-sub

▪️ Others (UV print, pad print, laser infill)

Top: Dye-sub PBT, Bottom: Doubleshot ABS

Image Credit: @HoffmanMyster Also important when selecting a keycap set is kitting/compatibility, which we will cover in a later article. There’s a lot of meaty details to that topic. Materials
ABS

Image Credit: @Mugi812

ABS is easily one of the most commonly used materials in the injection molding industry (notably, LEGO are made of ABS). It’s durable, well understood, and very easy to work with. Because of this, it is the most commonly used material in keyboard keycaps, whether for mechanical keyboards or not. There is one big downside though - shine. Chemically, ABS is less resilient to the oils on our fingers and in our environment than both PBT and POM. For example, as with LEGO, acetone will destroy your ABS keycaps. I don’t expect anyone reading this to be covered in acetone while typing (that would be hard anyway, considering the vapor pressure of acetone, but this isn’t a chemistry lesson is it?), but some lotions and other substances found around us and on our fingers can have a similar effect on ABS keycaps over time. Despite the long-term issue of shine with ABS keycaps, the ease of manufacture and versatility of legend capabilities (it is far easier to make doubleshot ABS keycaps than from any other material) makes them a very common material of choice, particularly when designing complex color combinations that require doubleshot manufacturing. In terms of feel, ABS has a more classically “plastic” feel to it, resulting in a more high-pitched sound profile. If that sounds like a negative description and you haven’t tried ABS, don’t write it off based on that though, a quality thick ABS keycap set is nothing to scoff at. PBT

Image Credit: @HoffmanMyster

PBT as a material addresses the one issue with ABS, introduces another problem, but solves it in a unique way. PBT is chemically resistant to pretty much all oils and greases that you would naturally expose it to, so it is very hard to shine a PBT set - awesome. On the flip side, PBT is harder to process and until the last decade or so there were no doubleshot PBT sets available. Even with the existence of doubleshot PBT sets now, they are not terribly common in the enthusiast space and for some reason most of the sets I’m aware of are on the lower quality side of things (not really sure why that is, but if you know of some premium doubleshot PBT sets that I’ve missed, let me know!). That’s not to say they’re bad sets, but when you get really picky about legend quality it becomes harder to find perfect quality sets. Despite the shortcomings of PBT as a doubleshot material candidate, it does have one great trick up its sleeve. PBT can have legends applied using the dye-sub legending process (detailed below), which results in equally durable legends as doubleshot keycaps. They do have one small drawback in terms of color combination options, but overall they are very nice keycaps and preferred by many enthusiasts. In particular, PBT is sought after by many for its softer and more …forgiving…(?) feel. It’s a very comfortable typing experience - if the colorway/theme you’re after is available in PBT, you really can’t go wrong. POM

Image Credit: @kahboom POM is a weird one. It has an even softer and more comfortable feel than PBT, making it similarly sought after for those after the best hand feel in their keycaps. In terms of processing options, however, it is much more limited. I’ve yet to see any POM caps which are printed with legends, and most are translucent white or other pale/milky colors. If that’s not your style, you’ll probably want to head back to the land of ABS or PBT. But for those that are into it, POM is said to be the best option around. I’ve actually only had the pleasure of typing on it once in my life though - keycap sets can be hard to come by and are a lot less common. Legending Technique
Doubleshot

Image Credit: Drop.com

Doubleshot manufacturing of keycaps is the process of shooting one color of plastic into a small cavity, then injecting a different color of plastic around that initial shot of plastic to form the rest of the keycap. Doubleshot keycaps are incredibly robust in terms of legend durability because you can’t rub the legend off - it’s physically built into the keycap. This means that even if finger oils were to eat away at some microscopic layers of the cap, it will have no noticeable effect on the legibility of the lettering itself. Tripleshot

Image Credit: Drop.com Tripleshot manufacturing is doubleshot plus one more - literally. There is an initial shot of plastic to create one legend, a second shot to create a sub-legend elsewhere on the keycap, then a final injection to encapsulate both and form the overall keycap shape. In terms of durability, tripleshot keycaps are identical to doubleshot keycaps.

Aside:

The one place where triple and doubleshot diverge is if the keycap set is doubleshot and includes sublegends of a different color. Because those sublegends cannot be injection molded in a doubleshot manufacturing process (that would make them tripleshot and more expensive), they are most often UV or pad printed. As a result, the sublegends included on doubleshot keycap sets with other-colored sublegends are less robust and more prone to rubbing off.

Dye-sub

Image Credit: @XiK

Dye-sublimation is a technique used to transfer “ink” (the dye-sub industry may have a different name for it) from a substrate onto/into the surface of a keycap. The process doesn’t literally sublimate the material - it’s a bit of a misnomer - but does cause the legend coloring to diffuse into the surface of the keycap. This diffusion of material into the keycap results in a similar level of robustness as observed with double and tripleshot keycaps. Because the legend is literally baked into the keycap itself below the surface, some layers of material can be removed and the legend is still present. As you can imagine, dyeing a dark material with a lighter material (white legends on black keycaps, for example) is unlikely to yield successful results. One inherent limitation to the dye-sub process is that the legends must be darker than the overall keycap color. There are some small-scale “reverse dye-sub” processes floating around that dye the entire keycap except for the legend, but this is less common and I haven’t had the chance to inspect any myself - your mileage may vary. One additional potential downside to dye-sub legends, particularly with lower quality sets, is the possibility of legend bleed. The legend ideally should only diffuse down into the keycap, but sometimes it will diffuse to the sides and create a fuzzy/blurry effect around the legend. Higher quality dye-sub sets will usually not have this issue, but it’s something to be aware of when looking. Others (UV print, pad print, laser infill)

Image Credit: @HoffmanMyster The “others” category here is mostly all the legend techniques used for cheap keycaps on membrane boards you’re used to. UV print is generally considered to be more durable than pad print, but both can/will wear off with extended use. Laser infill is a little more durable, but ends up looking pretty cheap - cavities are etched into the top of keycaps and then filled in with coloring. You can feel the etching when you use the keycaps and it’s generally just not a great experience. There are two instances I can think of where you should consider a set with one of these techniques. The first is something like the Keysterine keycap sets (or any other printed clear keycap). Because these caps can’t be made from PBT and still be clear, they also can’t be dye-subbed; doubleshot would inherently not be a totally clear keycap. This leaves UV print as the only option. Thankfully it is possible to add an additional protective layer to UV printed keycaps which improves the durability, but they are inherently less durable than the other techniques. The second is a doubleshot tri-color keycap, like the GMK cap pictured above. Considering how uncommon tripleshot keycaps are at this point and the high quality of GMK overall, they are a great option if you're after a tri-color cap. A keycap like this is also a good candidate for the dye-sub process, but that won't always be an option for the particular design you're after. Which material and legend combination do you prefer? Edit: Formatting

(Edited)

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Jan 18, 2023

what is the name of the purple keyboard in the first photo?

HoffmanMyster

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Jan 18, 2023

kyo1It's a Fancy66 (original post)

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Plexiform

Jan 4, 2023

Why no mention of metal keycaps? Some custom manufacturers offer Silver or Stainless Steel keycaps which look amazing. Are those worth the expense? Stainless steel set of keycaps for a 100% keyboard will cost $2k. Silver would be 5x that.

(Edited)

HoffmanMyster

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Community

Jan 4, 2023

PlexiformMight be worth mentioning metal, but it's fringe enough (and costly, as you pointed out) that I don't think it's vital to an intro/primer article. They're fun novelties, but metal caps almost always end up being more of a pain than they're worth. You need to mod or swap switches to accommodate the increased weight, they usually ping like crazy, and often they don't seat properly on switch stems. People have done it and seem to enjoy them, so YMMV and to each their own, of course. :)