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Switch films: small gasket, specific job

Switch films show up in nearly every switch modding guide, often with vague promises about better sound. They do one specific thing well. Here is what that is, when it helps, and when you can skip them.

An MX-style switch housing is two plastic halves that clip together. Mass production leaves a little tolerance in that fit, so on some switches the top housing can shift slightly against the bottom one. When you press and release the key, that looseness can add a faint rattle or a hollow, clicky quality to the top-out and bottom-out. A switch film is a thin gasket, cut to the shape of the housing, that sits between the halves and takes up that slack.

What films change

  • Housing wobble. The main effect. The two halves sit tighter, so the switch feels more solid when you rock the keycap.
  • Sound. A tighter housing tends to sound a little fuller and less rattly, particularly on the upstroke. The change is subtle on most switches.
  • Consistency. Filming can even out key-to-key differences on a batch of switches with variable tolerances.

What films do not change

This is where many guides overpromise. Films do not affect:

Which switches benefit

The simple test: hold a switch by its bottom housing and try to wiggle the top housing, or listen closely as you press and release a key. If the halves move or the switch ticks on release, films will help. If the housing is already tight, they will not do much.

Many modern switches are designed with tight housings and do not need films. The Gateron Ink switches, for example, are commonly reported to be tight enough that filming adds little or makes them hard to close. Older designs and budget clones are more likely to benefit. Because tolerances vary between production runs, the most reliable guide is to test a few switches from your own batch before filming all of them.

Materials and thickness

Films are commonly made of PC, PET, or a paper-like material, and some brands sell their own blends. In practice the differences between materials are small compared with getting the thickness right.

Films are usually sold in thicknesses around 0.1 to 0.2 mm. Thinner films suit switches that are only slightly loose. Thicker films take up more slack but can make a housing difficult to close, and a housing forced shut over a film that is too thick can bind the stem. If a filmed switch feels gritty or sticky compared with an unfilmed one from the same batch, remove the film.

How to install them

  1. Open the switch with a switch opener and lift off the top housing.
  2. Place the film on the bottom housing, aligning its holes with the pins and the LED window.
  3. Put the stem and spring back, then press the top housing down until both clips click.
  4. Press the stem several times to check for binding or scratchiness.

Films are almost always installed at the same time as lubing or spring swapping, since the switch is open anyway. Doing them on their own is rarely worth the effort of opening every switch. Our spring swapping guide covers opening switches in more detail.

Should you bother?

If you are lubing a set of switches that have loose housings, films are a cheap, worthwhile addition. If your switches are tight, skip them. If you are not opening your switches at all, films are not a reason to start. The upgrades that make a bigger difference to most boards are listed in our overview of keyboard sound mods.

Frequently asked questions

What do switch films do?

A switch film is a thin gasket placed between the top and bottom housing of a switch. It fills the small gap left by manufacturing tolerances so the two halves sit tighter, which reduces housing wobble and can make the bottom-out and top-out sound a little more solid and less rattly.

Are switch films worth it?

On switches with loose housings, often yes, especially if you are already opening them to lube. On switches whose housings already fit tightly, films make little difference and can even make the housing too tight to close properly. They are not a fix for scratch, ping or stem wobble.

Do switch films reduce stem wobble?

Not really. Films tighten the fit between the two housing halves. Stem wobble is the stem moving inside the top housing, which films do not touch. Switches with tight stem tolerances or longer stem guides are the fix for stem wobble.

What thickness of switch film should I use?

Films are commonly sold in thicknesses around 0.1 to 0.2 mm. Thinner films suit housings that are only slightly loose. If a filmed switch is hard to close or the stem binds, the film is too thick for that switch.

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