Is modding safe?

Hello there.

I’m thinking of modding a cheap keyboard for content. I was searching for foam to do polyfill mid, then I thinked something, I thought that if I did polyfill, pe foam, and tape mod on a wired keyboard, will it be safe?

In my opinion, I think it’s safe and the only thing unsafe is tape mod on battery. But I am not too sure. So I’m asking you guys because I feel like you might know better than me.

The thing I’m worried is that a fire could occurs which is totally scary!

So the question here is;
Q1: Is PE Foam, Tape, and Polyfill, and other modding safe to be applied on wired keyboards and maybe wireless keyboard.

Thanks in advance.

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What danger does the tape add that isn’t already there because of the Li-Ion battery?

Some tapes are conductive, which can cause shorts that could start a fire. However, most are not, so that is unlikely to be an issue, and it is easy to check the conductivity of a particular tape with a multimeter.

Some materials are flammable and could serve as kindling, but that is only an issue if some of the electronics are overheating, which typically should not be the case, unless it is malfunctioning. However, adding materials inside the case could add a bit of thermal insulation and slightly increase the likelihood of dangerous overheating. Batteries and power components do tend to normally get a bit warm, and a potential malfunction is to get hot enough to start a fire. However, if a lithium-ion battery catches fire, it’s already a great risk on its own, regardless of a bit of tape and foam as additional kindling.

Overall, these additional risks may be quite small, but are not completely zero. The incremental risk might not be significant compared to the baseline risk of a lithium-ion battery. I’ve seen some put little cut outs in their tape mod for various electronic components that they worry might get too hot, but there are many, including myself, that have not and have not run into issues. I even put felt as sound damping material in one of my keyboards. However, I did confirm the non-conductivity of the tape that I used, and I am generally paranoid in avoiding any keeb with a lithium-ion battery.

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By the time paper tape catches fire, the PCB and battery have already been in flames for a while.

It’s generally too late to avoid Li-Ion batteries since they are everywhere.

Laptops are far more testing use cases for batteries, they all use Li-Ion, and only a very small number catch fire every year. Keyboards operate on low drain and at room temperature.

If keyboard batteries worry anyone then they should not own a laptop or an electric vehicle.

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I would hope that a board of FR-4 is more fire retardant than masking tape! :nerd_face:


FR4 melts at 120C and burns after reaching 140C. Painter’s tape burns at 350C. The paper smoke is noxious but survivable, inhaling the FR4 smoke has several ways to kill you.

Modding keyboards is perfectly safe as long as one isn’t crazy. Although I will not be surprised when I see that someone is recommending lining the case with C4.

hmm… c4 you say :thinking:

Good sound absorption maybe.


Those temperatures are surprisingly low!

So I did some searchengineering and it seems the typical FR-4 Tg (glass transition temperature) is about 130 C, and the Td (decomposition temperature) is around 350 C — which makes sense given typical soldering temperatures.

As far as I can tell, the UL-94 flammability test involves holding the specimen in a normal methane gas flame, which is around 1000 C. If the FR-4 gets the V-0 rating it burned for less than 10 seconds after the flame is removed.

Having said that, when a spicy pillow lets go it can get a lot more challenging than a tickle from a bunsen burner :person_shrugging:


Wow thats really informative. But is pe foam modding and case foam modding (eva, Polyfill, etc) any safe? Since tape on lithium ion batteries feel unsafe for me, after I read a switch and click article.


“By the time paper tape catches fire, the PCB and battery have already been in flames for a while.”

I guess that’s true knowing that paper is easily burnt and spreads fire fast, so even if we did extinguish it, the PCB will already be dead by the time we tried to extinguish it, just like you said.

“It’s generally too late to avoid Li-Ion batteries since they are everywhere.”

Yes, indeed they are everywhere, I’m guessing in the future everything, even keyboards would go battery type. But even now, cheap keyboards have batteries in it!

“If keyboard batteries worry anyone then they should not own a laptop or an electric vehicle.”

I guess it’s true. The truth is, laptops have batteries and are enclosed without heatsinks (only thing that helps sink the heat is probably the protection layer), so I’m saying, why are keyboards more of a fire hazard than laptops? Laptops in fact use more energy and laptop batteries get pretty hot when put on charging mode while gaming or productivity.

Good sound absorbing item because you’d be deaf for a few minutes lol.

So FR4 smoke is just like the effect of smoking cigarettes for years lol.

Thanks for letting me know that modding is safe, but is tape mod or any type of mods safe on lithium ion keyboards?

I mean… Not everywhere. Certainly not in keyboards, where the high end stuff is mostly still wired only.

Out of a dozen or so keyboards I only have two wireless ones and they both run on AAs.

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Skipping the tiny implied sneer at some people’s keyboards, you’re wrong. Phones, laptops, home automation, electric cars/bikes/scooters/boats, flashlights, to name a few.

It’s a question about modding keyboards. On a forum about keyboards. Where pretty much every conversation revolves around custom keyboards. Removing all context from the question to make a point isn’t helpful to anyone.

It is extremely easy to avoid keyboards with lithium ion batteries. You don’t really need to, but it isn’t “too late to avoid” by any stretch of the imagination.


Please explain to me why Li-Ion batteries are terrifying fire risks when in a keyboard but not in a phone or a laptop.

I have to add that, in all honesty, it looks like you are playing deliberately obtuse to start a fight. I’m sure you have your reasons, but they aren’t clear.

I’m not trying to start a fight at all, and I don’t know why you think I’m being obtuse. If my comment seemed inflammatory, I’m sorry. I just thought it was odd that you said Li-ion batteries are unavoidable and I left a comment saying such without thinking much about it.

As for this:

I said nothing of the sort and I don’t know why you’re putting words in my mouth. @yeeb is the one who said they deliberately avoid them. In the context of modding a keyboard by putting flammable materials like polyfill in direct contact with electrical components. I don’t think it’s the idea that the battery may spontaneously combust that’s the problem, more that if a bunch of polyester started a small fire next to a battery it may end up becoming a big fire.

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@Marksmad and @Laughmaster

Let’s not call names and argue with a seemingly angry tone.

‘‘Please explain to me why Li-Ion batteries are terrifying fire risks when in a keyboard but not in a phone or a laptop.’’

Sadly, I cannot explain as I am not an expert.
But in my opinion, it’s because most of the time, people who buy laptops or phones don’t modify it (Except changing ram or storage on a laptop, which is safe.). Meanwhile most people in the keyboard community modify their keyboards, and this creates a risk since the ways of modification are made by keyboard enthusiasts, not companies. But it seems companies have started to apply these modifications on their keyboards, such as PCB foam, switch foam, etc.

So, I would say modding on a Li-Ion battery type keyboard is safe, but I’m not 100% sure if it’s safe to tape mod Li-Ion battery type keyboards. Since most people in the keyboard community use paper type tapes with low conductivity, instead of electrical tape which has higher conductivity, despite electrical tape could be more safe.

Thanks @yeeb Your solution is really helpful for me.