DIY : Adding H-EVA sound dampening foam to my MiniVan – Hung – Medium

There was a recent sale by u/parallelojam on reddit for H-EVA foam. These foams were meant to dampen the sound of the keyboards when typing and possibly remove ping, sample sounds can be seen in parallelojam’s original post. Sounded interesting so I bought some😜.

This is a small log on how I added the foams to my MiniVan with Clear Minded Pandas (Cherry MX Clear in Invyr Panda housing and spring) and my opinion on the results. First time foaming 😃.

Method

Firstly, the foam itself:

Foam came in!

Quoting parallelojam :

It is comprised of H-EVA, which is ethylene-vinyl acetate, but has a higher proportion of VA so has a denser, more rubberised texture.

One side is a smooth foam surface which gives you the option to stick down flat with double-sided tape, and the other side has a small, egg box-like construction that helps dampen impact sound. More than anything else though, is that it does wonders for reducing that annoying pinging sound in aluminium cases and being only 1.5mm thick, you can layer it up for additional benefit if you have the space.

The foam was the 40% size and the dimensions were fairly larger than my MiniVan so it should cover pretty much any 40% keyboards. Of course this meant it was necessary to cut it down.

  1. I measured the dimensions of the hollow area in the MiniVan case. It was about 24.2cm in length and 7.8cm in width for mine, but don’t take these measurements if you have a Minivan, its probably better to do measurements yourself just ‘in case’ 😝once its cut, it won’t grow back.
Measured and traced

2. Once I cut the foam, I fitted it into the case. Some slight mis-measurement as seen in the picture below, so I had to cut a little more on the longer side.

Some screw holes are circled in red

3. In order to locate the screw holes to cut, I pressed the foam down with some pressure on the case so that I can see the protruding screw holes (circled in red above). This resulted in the screw holes leaving an imprint on the flat side of the foam.

Imprints of screw holes, easy to cut!

This made it so much easier to know where to cut the holes out.

4. I cut the holes by poking a screwdriver through the imprints, not an engineer so just did what worked 😛.

Finish 😃

5. After the holes were cut, I fitted the foam into the case. With some pressure, the screw holes poked through the cuts and essentially enlarged it, resulting in a very nice fit. Could be cleaned up further by getting rid of the cut trails.

Sound Trials

Reassembling my MiniVan, here’s the difference in sound, sorry for potato quality.

Before foam
After foam

Opinions/Verdict

Ping

Without the foam, the ping from the aluminium case is both loud and deep, in my opinion. Very noticeable in the sound trials. After the foam was added, the ping was definitely less noticeable. It is still there and also has a slightly higher pitch. Overall it does reduce ping from aluminium casing.

Typing Sound

My Minivan used Clear Minded Pandas and DSA keycaps so the vanilla sound is pretty clacky.
The foam took away the reverb of the case and it has a noticeably clearer and cleaner clack. clack is niceee 😃
In terms of volume, for my board it did not decrease by much, if anything the clack is emphasised (oh so sweet and satisfying) and sounds a bit more noticeable. But in other boards it may sound quieter, as in parallelojam’s same videos.

Feel of the board

Decided to write something about this because it has changed. In hindsight, when I typed on this board without the foam, I felt a sense of hollowness beneath the switches, like punching a thin wall. With the foam, the typing feels a lot more solid, like punching a very thick wall. This could potentially be the feedback from the switch sound thats doing the trick, but with the hollowness under the plate being filled by the foam, this feeling makes sense anyway.

Evaluation

Two things I could have done to improve.

I could have done was trim the trails of the screw-hole holes on the foam, but I am lazy 😄.

I could also add a layer in between the plate and the PCB. Since I did solder the Panda hot swap sockets onto the PCB (bad idea? probably), I can do this rather easily, but will need to find the time as cutting the holes for the switches will be effort. Luckily with a 40%, this would not be a overly time consuming job.

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