When building a custom mechanical keyboard, switches and cases get most of the attention. But the part your fingers actually touch – the keycaps – matter just as much. The two most common materials are ABS and PBT. Which one should you choose? Let’s break it down.

• ABS (Acrylonitrile Butadiene Styrene): A soft, smooth plastic. Most factory keyboards come with ABS caps.
• PBT (Polybutylene Terephthalate): A harder, more durable plastic with a slightly textured feel.

Pros and Cons

ABS – The Classic Choice

• ✅ Crisp colors, great for intricate custom keycaps designs
• ✅ Smooth feel preferred by some typists
• ❌ Develops an oily shine within weeks or months
• ❌ Less resistant to cracking

PBT – The Long-Lasting Workhorse

• ✅ No shine – stays matte for years
• ✅ More rigid, resistant to heat and chemicals
• ✅ Deeper sound profile
• ❌ Can be harder to mold into very thin or complex shapes
• ❌ Some cheaper PBT caps feel rough or have warped spacebars

Which One Should You Pick for Your Custom Mechanical Keyboard?

• Go with ABS if: You love vibrant,, don’t mind regular cleaning, and prefer a smooth, slightly soft touch.
• Go with PBT if: You want a set that will look the same after two years of daily use, prefer a textured grip, and like a deeper “thock” sound.

Many builders keep both: a flashy ABS set for show, and a reliable PBT set for everyday work.

Neither material is “better” – it’s about your priorities. ABS shines in color and smoothness (literally and figuratively). PBT shines in longevity and texture. For a custom mechanical keyboard you plan to use every day, PBT is often the safer bet. But if you love collecting custom keycaps as art pieces, ABS offers unmatched vibrancy.

Whichever you choose, remember: the best keycaps are the ones that make you want to type.

Looking for more keyboard guides? Check out our Custom Keycaps Buying Guide.