Thanks to everyone for the advice, I'm glad I asked. It never occurred to me about the issues I'll have with a solvent based spray and it looks like the product I'll be using does have acetone as an active ingredient.
@Oobly
Is there any chance you have a link to any info on your "latex" mod? Thanks
@0100010
"Or is it going to be a very loose bond, where after a few keystrokes it will start to delaminate and cause issues."
This is a real concern, I can see this happening over time or when removing any small pieces of masking tape causing some rubber to come loose dropping debris on to the pcb.
@spicebar
Your mod sounds superb and exactly what I want to achieve, are they the pads from elitekeyboards? my only concern is the pads expand over time and return to their normal width. This may have an effect on the travel distance of the slider altering the tactile feel as reported on a similar mod on a realforce.
"- Spraying the plate would be mostly useless. The click sound on the upstroke is caused by the slider hitting the inside of the switch housing. That's were you want to put some rubber."
I agree, one option of my plan was to spay the underside of the housing like in the image and possibly in a few other locations
Show Image
Photo credit: elitekeyboards
I only have an issue with 3 keys (which are all stabilised) and your mod isn't as destructive as my idea so i'll probably give your idea a shot, thanks.
Yes, these are the soft landing pads (black ones) from EliteKeyboard.com.
In your picture, you do not have to worry about the keycap touching the top of the housing. It does not happen, because the slider has little legs (see pictures below) and these legs hit the rubber sheet above the PCB
before the keycaps can come in contact with the switch housing. The legs touching the bottom rubber is what makes the "thock". If the keycaps came in contact, the noise would be a "click" similar to the one on the upstroke. But they don't.
For this reason, I still do not understand why CM includes O-rings with the keyboard. They cannot do anything. The O-rings are smaller than the circumference of the slider, so there is really no way they can help the same way they help in Cherry MX switches. However there is one thing they can do: they can make the keycap
taller, and it is possible that some keycaps could touch the side of the housing without O-rings. In this case, including O-rings is a waste of rubber: rings made with hard plastic would do exactly the same thing.
So either CM does not understand what they are doing, or they do understand it but they think it's too complicated to explain to us and that we will be satisfied with "O-rings = sound dampening". Or it just happens that they have loads of O-rings in stock and it's cheaper for us to provide them instead of hard plastic rings.
Anyway... No noise happens on the top of the housing and it does not serve any purpose to put rubber over there. Unless you have keycaps with strange shapes.
The only place you need to add rubber is
inside the switch.
Here are pictures that will help in understanding what happens, but please keep in mind that these pictures are not 100% accurate. They are just meant to explain the "click" on the upstroke and how to get rid of it:
Without sound dampening:
With sound dampening (a landing pad has been installed inside the switch):
Please note that the landing pads are much thinner in reality than on this picture.
You can find a step-by-step of the mod I did initially on the FC660C here:
https://geekhack.org/index.php?topic=49046.0What you do is that you follow this procedure, but at step 4 you insert a new step:
You take a clothing iron, you set it to the highest temperature, and you iron the landing pads as hard as you can. You must put them inside a folded sheet of paper to avoid direct contact with the iron, because they may burn.
Actually, depending on the power of your clothing iron, they may burn even inside the sheet of paper. So experiment with just one landing pad at a time until you find the right setting. When the landing pads start to stick to the paper, your iron is a little too hot. Just a little. It may be good at this temperature as long as you can remove the pads from the paper. I have not experimented this: even at its highest temperature, my iron has not been able to burn the pads.
Using the highest possible temperature before they burn guarantees that they will not return to their initial width. There is some melding happening here, so they will stay like that.
In my previous mods, I had started using this method, but I was afraid to slim the pads all the way down. When they were too slim they started to "climb" on the slider a little bit and I thought this would jam the switch. I was wrong.
So I was using pads that were between 1mm=0.04inch (first experiments) to just 0.4mm=0.016inch. There was a small change in the feel of the Topre switch.
Now I slim them down to between 0.15 to 0.20mm (0.006 to 0.008inch), and there is absolutely no change in the tactile feel of the switch. The upstroke noise is still dampened.
Here is what they should look like before and after "processing":
Obviously, the two in the middle have not been ironed... Yet! :)
Then you install these pads on the slider (they are more like a sheet of rubber at this point):
They do climb a little bit on the slider, but it turns out that it does not matter, thanks to the shape of the housing. The mechanical action of the upstroke will secure them in this position. They cannot climb any higher.
With the picture above, you get an idea of the width of the landing pad: the edge on which the pad sits is approximately 1mm in width (0.04inch). On the picture you can see that the landing pad is less than 1/5 of this. It's between 0.15 and 0.20mm (between 0.006 and 0.008inch) when it is free. Once inside the switch, it will be slightly compressed by the rubber dome and the conical spring under it, so I'm pretty sure we are talking about a reduction of 0.15mm here (0.006inch). It represents less than 4% of the key travel.
The pad's orientation is important:
On the stabilized keys, you install it like this:
Finally, the rattle of the stabilized keys can be dampened with thick silicon or lithium grease, like this:
I plan to post a complete description of the mod, but here you have the essential points covered with pictures.
Good luck! :)
