Question Identification of keyboard dampening foam ?

[ShangWang]

I found this 4mm thick foam in my room that I could potentially use for dampening my HyperX Alloy Origins but I'm not sure what kind of material it is or if it's appropriate for the task. I just know that if the foam is not electrically conductive, it would work.

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The foam is a bit hard, with some rigidity and has a somewhat smooth texture with little pores. Does anyone know what material this is? Would it be good for keyboard dampening?

 

[Ralston18]

Appears to be styrofoam but I do not see the individual "pellets" common to styrofoam.

Do little tiny, round pieces come loose and then start sticking (electrostatic) to things?

Does the pad sort of squeak or crunch when gently flexed or bent?

That said:

How are you planning to actually use the foam: for example, just as a pad for under the entire keyboard?

No harm I think in giving the foam a try. See if it works to quiet down the keyboard noise.

 

[Eximo]

Looks like EVA foam perhaps? Usually found in yoga mats and stuff.

Perhaps a slightly more porous mix then what is commonly used in matting.

 

[ShangWang]

Looks like EVA foam perhaps? Usually found in yoga mats and stuff.

Perhaps a slightly more porous mix then what is commonly used in matting.

I see, if it was EVA foam it would not be electrically conductive and therefore fine to use?

 

[ShangWang]

Appears to be styrofoam but I do not see the individual "pellets" common to styrofoam.

Do little tiny, round pieces come loose and then start sticking (electrostatic) to things?

Does the pad sort of squeak or crunch when gently flexed or bent?

That said:

How are you planning to actually use the foam: for example, just as a pad for under the entire keyboard?

No harm I think in giving the foam a try. See if it works to quiet down the keyboard noise.

It's pretty rigid and doesn't really make any noise if I press it with my fingers, just soft pressing noises. It doesn't seem to tear apart easily or come out in little pieces, it is definitely some type of foam but I don't know what and if it's ok to use for keyboard dampening. How would I know if it's safe/not electrically conductive?

I'm planning to put it on the bottom base plate of my keyboard, right under where the PCB would rest.

 

[Ralston18]

Do you know where the foam came from?

There are non-electrostatic materials available for packaging electronics.

For example:

https://www.amazon.com/Multicomp-Density-Non-Corrosive-305x305x6mm-2-Pieces/dp/B071G74PGW

You can easily google for other similar products and information.

Very much doubt that the foam is electrically conductive. However, the foam could build up a surplus of electrons that eventually will create a spark as soon as the electrons find a path to ground/earth. Possibly through the bottom base plate, the PCB, and the cord....

Rub the foam. Try a piece of dry cloth. Rub the foam on a rug. Determine if the rubbing creates a surplus of electrons in the piece of foam.

If doing so results in a static build up then the foam will likely attract bits of paper, maybe hairs; the foam might stick to a wall or ceiling as can be done with an electrostatically charged balloon.

Or you might see or hear a spark much as in any situation where a static discharge occurs. More likely in cooler, dryer environments than in warmer, more humid environments.

May also depend on the surface where the foam rests: metal, wood, glass, plastic.

If the foam does not build up excess electrons then all should be well.

 

[Eximo]

EVA foam is often used for electronics packaging, but that is likely doped with metal to make it ESD safe.

I wouldn't think it would be a big deal under a keyboard or key-cap since it would more or less remain in contact with a grounded surface (unless the keyboard is wireless)

 

[ShangWang]

EVA foam is often used for electronics packaging, but that is likely doped with metal to make it ESD safe.

I wouldn't think it would be a big deal under a keyboard or key-cap since it would more or less remain in contact with a grounded surface (unless the keyboard is wireless)

Thanks, I'm not too informed about what makes a surface 'grounded.' The keyboard is wired and is on a wooden table. What exactly would make the keyboard 'grounded?'

Even if the foam was slightly conductive, you're saying it would not be much of an issue?

 

[Eximo]

Thanks, I'm not too informed about what makes a surface 'grounded.' The keyboard is wired and is on a wooden table. What exactly would make the keyboard 'grounded?'

Even if the foam was slightly conductive, you're saying it would not be much of an issue?

Actually no, quite the opposite.

Ground or neutral is tied back through the power supply chassis into the wall into, literally, the ground. Most homes have a metal rod that is sunk into the dirt somewhere.

So your USB ports are grounded, the cable to your keyboard is grounded internally, and your keyboard either has a metal or plastic surface also connected to the neutral at some point. Consumer electronics plastic is usually embedded with metal compounds in the mix for injection molding. That way the plastic can carry current and continue the path to ground. That is why if you get your keyboard wet, it isn't too dangerous since all the potential will short to ground rather than go through your body/skin to find a way to ground. The metal also prevents stray signals generated by devices from getting out, making them EMI rated.

ESD safe is quite straightforward, just means the surface is conductive so that any potential difference is quickly eliminated. That dark tint to common anti-static bags is a metal coating. (Or sometimes black lines painted on with metal bearing paint). Also the pink and blue ones, not actually sure what chemical that is, might look into that later. ESD wrist straps are literally a wire that goes around your wrist and you connect to a grounded surface.

On the positive side a lot of foams and plastics contain metal, not just intentionally, but also as part of the manufacturing process. Lots of polymers are kicked off to polymerase by metal catalysts. A good example is PVC which contains a bit of copper (Which is why they aren't too bad for drinking water since they still have the anti-microbial properties). Nickel is also common, and for very white plastics, often Titanium.

Wooden tables are pretty well insulated, so you could build up a potential difference, but a lot of wood surfaces also contain some amount of moisture and aren't terrible. Not issue since your computer is grounded as mentioned.

 

[ShangWang]

Actually no, quite the opposite.

Ground or neutral is tied back through the power supply chassis into the wall into, literally, the ground. Most homes have a metal rod that is sunk into the dirt somewhere.

So your USB ports are grounded, the cable to your keyboard is grounded internally, and your keyboard either has a metal or plastic surface also connected to the neutral at some point. Consumer electronics plastic is usually embedded with metal compounds in the mix for injection molding. That way the plastic can carry current and continue the path to ground. That is why if you get your keyboard wet, it isn't too dangerous since all the potential will short to ground rather than go through your body/skin to find a way to ground. The metal also prevents stray signals generated by devices from getting out, making them EMI rated.

ESD safe is quite straightforward, just means the surface is conductive so that any potential difference is quickly eliminated. That dark tint to common anti-static bags is a metal coating. (Or sometimes black lines painted on with metal bearing paint). Also the pink and blue ones, not actually sure what chemical that is, might look into that later. ESD wrist straps are literally a wire that goes around your wrist and you connect to a grounded surface.

On the positive side a lot of foams and plastics contain metal, not just intentionally, but also as part of the manufacturing process. Lots of polymers are kicked off to polymerase by metal catalysts. A good example is PVC which contains a bit of copper (Which is why they aren't too bad for drinking water since they still have the anti-microbial properties). Nickel is also common, and for very white plastics, often Titanium.

Wooden tables are pretty well insulated, so you could build up a potential difference, but a lot of wood surfaces also contain some amount of moisture and aren't terrible. Not issue since your computer is grounded as mentioned.

So it would be a good thing that my foam might be electrically conductive so that it doesn't have any ESD? I thought it was bad for it to be electrically conductive if it had added metal?

Would it be better if the foam had more electrical conductivity, or less prone to having a static discharge?

 

[ShangWang]

Do you know where the foam came from?

There are non-electrostatic materials available for packaging electronics.

For example:

https://www.amazon.com/Multicomp-Density-Non-Corrosive-305x305x6mm-2-Pieces/dp/B071G74PGW

You can easily google for other similar products and information.

Very much doubt that the foam is electrically conductive. However, the foam could build up a surplus of electrons that eventually will create a spark as soon as the electrons find a path to ground/earth. Possibly through the bottom base plate, the PCB, and the cord....

Rub the foam. Try a piece of dry cloth. Rub the foam on a rug. Determine if the rubbing creates a surplus of electrons in the piece of foam.

If doing so results in a static build up then the foam will likely attract bits of paper, maybe hairs; the foam might stick to a wall or ceiling as can be done with an electrostatically charged balloon.

Or you might see or hear a spark much as in any situation where a static discharge occurs. More likely in cooler, dryer environments than in warmer, more humid environments.

May also depend on the surface where the foam rests: metal, wood, glass, plastic.

If the foam does not build up excess electrons then all should be well.

Gotcha, so if it does not build up those electrons that would mean it's electrically conductive right? Wouldn't this be what I don't want, or is what I was told incorrect about electrical conductivity being bad? Is the risk of ESD worse?

I believe the baseplate of the HyperX Alloy Origins is made of aluminum on the exterior, but the interior is plastic. Does this have any negative effect?

 

[ShangWang]

Do you know where the foam came from?

There are non-electrostatic materials available for packaging electronics.

For example:

https://www.amazon.com/Multicomp-Density-Non-Corrosive-305x305x6mm-2-Pieces/dp/B071G74PGW

You can easily google for other similar products and information.

Very much doubt that the foam is electrically conductive. However, the foam could build up a surplus of electrons that eventually will create a spark as soon as the electrons find a path to ground/earth. Possibly through the bottom base plate, the PCB, and the cord....

Rub the foam. Try a piece of dry cloth. Rub the foam on a rug. Determine if the rubbing creates a surplus of electrons in the piece of foam.

If doing so results in a static build up then the foam will likely attract bits of paper, maybe hairs; the foam might stick to a wall or ceiling as can be done with an electrostatically charged balloon.

Or you might see or hear a spark much as in any situation where a static discharge occurs. More likely in cooler, dryer environments than in warmer, more humid environments.

May also depend on the surface where the foam rests: metal, wood, glass, plastic.

If the foam does not build up excess electrons then all should be well.

I noticed that cutting off a piece and rubbing it over a carpet did not attract pieces of hair at all, but if I rubbed the whole roll of foam over carpet and dropped pieces of hair close to it, the hair will fly towards the roll. It will not however pick up hair like a magnet by just getting close to hair, but if hair drops near it. I suppose this means the foam is not electrically conductive, but it might cause ESD?

If I move my finger towards the pieces stuck on the foam, the hairs will slightly move. What does this mean? Does it mean my finger has static built up on it too?

 

[ShangWang]

EVA foam is often used for electronics packaging, but that is likely doped with metal to make it ESD safe.

I wouldn't think it would be a big deal under a keyboard or key-cap since it would more or less remain in contact with a grounded surface (unless the keyboard is wireless)

I think the material might likely be EVA foam, since my sister said that it was used for cosplay from a friend.

The texture does look similar. If this is likely to the case, is 4mm generally too thick for padding? Is it bad if the foam were to make contact with the PCB, or is this ok? When would it be too thick?

 

[Ralston18]

Appears that the foam can build up a charge.

However between possible paths to ground via the keyboard (as described by @Eximo) and you (fingers on keyboard) any build up is not likely to be a problem.

I have inadvertently zapped my systems a couple of times via wired keyboards. I just rebooted and all was well.

Very much in the habit of touching my PC case or a file cabinet before typing - even though I mostly use wireless (BT) keyboard and mouse.

 

[ShangWang]

Appears that the foam can build up a charge.

However between possible paths to ground via the keyboard (as described by @Eximo) and you (fingers on keyboard) any build up is not likely to be a problem.

I have inadvertently zapped my systems a couple of times via wired keyboards. I just rebooted and all was well.

Very much in the habit of touching my PC case or a file cabinet before typing - even though I mostly use wireless (BT) keyboard and mouse.

Gotcha, thanks. I was also wondering if it might be a good idea to use a small layer of scotch tape underneath the foam to let it stay on the bottom plate. Will this interfere with sound dampening if any/does it have any issues with ESD?

 

[Ralston18]

Should not interfere with sound dampening or ESD.

Start with small pieces of strategically placed double-sided tape.

 

[ShangWang]

Should not interfere with sound dampening or ESD.

Start with small pieces of strategically placed double-sided tape.

Ty, I don't completely understand the factors that go into grounding, but I'll look it up and come back to ask if I still don't get it.

 

[Eximo]

A common analogy used to explain current flow is water:

The key concept to understand is potential difference (ie voltage)

If I have a full bucket and a half full bucket sitting next to each other, nothing happens (6v and 12v). If I connect those two buckets at the bottom with a tube, water will flow from the full bucket to the half full bucket until the water levels are the same. (9v and 9v)

Ground, also known as the common, is always zero in respect to a circuit. So if I have a full bucket and a path to ground, the bucket will always be empty and at zero volts. Ground is also the lowest resistance path to zero in any protected circuit.

Static electricity is very high voltage, which can be damaging to low voltage circuits at the atomic level. By having a ground plane it makes sure any discharge that may happen will not go through the electronics, but straight to zero. This is why ESD safe materials must be conductive, and more conductive than typical electronics internal resistance.

Also why ground is a safety measure. Any short in the system that could be dangerous will go to ground, not through a person which has a higher resistance then the grounded circuit. This applies to electronics as well as electric appliances. Either the common and neutral are tied together (simple things like lights and fans), or there is a third ground prong to shield potentially much higher internal voltages from getting to a person.

Inside a PC power supply for instance, is roughly 170 volts DC before it gets converted to 12V, 5V, and 3.3 volt. 340 volts if you use 240V AC as input.


It is simplified though, as electric fields don't really work like that, but the math works when designing circuits. Water = current, buckets = capacitors, resistors equal different tube diameters, transistors (sort of) = valves. (Early vacuum tubes were called valves even)