Are Rubber Domes good?

[erricrice]

HA!  Now that I've got you interested, here's my real question:

Ok, so do any of you know anything about the technology of rubber domes?
There are at least two(probably more) types of domes in my opinion:
Rubber mush, which feel exactly like it sounds like it feels
and something else which I can't quite describe, but less mushy, more plastic feeling.
My question is about the second type of switch.  My girlfriend has an old gateway keyboard that she has had for about 6 years and the thing still works great and feel exactly the same as when she originally got it, she says.  Now it is the type of rubber dome that doesn't really have a mushy feel but almost feels like a cheap mechanical switch.  It doesn't have the tactile response of a mechanical switch, but it is somewhat louder than most domes and like I said it doesn't wear out like the mushy ones do in a week or so haha.  And also by not wearing out I mean that none of the keys stick or are difficult to push down like some of the crappy dells get after a few months.  I also had some keyboards like this that I used at the computer store that I worked in.   They were VERY well used but none of the keys stuck in place.

Is there a different type of rubber dome technology going on here?  How do these compare with the 'decent' rubber domes like the older IBMs?  


PS:  Does anyone happen to have a Filco with Cherry Blacks that they could post an audio clip of?  If so, please post said clip!

[JBert]

You're mentioning three things here:
-tactility
-friction
-noise

The tactility depends on the little details of the rubber dome layer: the way it is shaped, the material it's made of, it's age, ...
All of these affect it somehow, and cheap keyboards are more likely to use a cheaper material, use less of it or simply use some shape of dome which doesn't work out that well. Keyboards with a higher design standard will keep that "new" feeling a lot longer.

Regarding friction, I think it is purely the design of the keycaps, key stems and the upper keyboard plate in which the keystems fit.
If I compare my brother's Logitech keyboard with my old IBM KB-8923 it is immediately obvious that the IBM has more key travel, less friction and less wobling keys.
So far, I think this caused by the material of the key stem and the keyboard casing; the IBM keys seem to use a shinier material and their keystems are longer. This allows them to make more contact with the keyboard casing, making sure keys are pressed straight down.

As for the last one, the noise it makes: I think this must be caused by the material of the keycaps and the "springiness" of your rubber layer. The IBM keyboard I talked about sure clatters if you lift your fingers off the keys and let the key stem's clip hit the keyboard casing. The Logitech had less return force, hence it didn't make so much sound in that aspect.

[itlnstln]

The one common factor of all standard rubber domes is that they have to be bottomed out for the switch to activate. There are quality rubber domes, but many folks don't want to have to bottom out switches to type.
 
This is part of the appeal of Topres. They, from what I hear, are smoother and nicer in feel to average rubber domes, and they don't have to be bottomed out to activate the switch.

[erricrice]

You're mentioning three things here:
-tactility
-friction
-noise

The tactility depends on the little details of the rubber dome layer: the way it is shaped, the material it's made of, it's age, ...
All of these affect it somehow, and cheap keyboards are more likely to use a cheaper material, use less of it or simply use some shape of dome which doesn't work out that well. Keyboards with a higher design standard will keep that "new" feeling a lot longer.

Regarding friction, I think it is purely the design of the keycaps, key stems and the upper keyboard plate in which the keystems fit.
If I compare my brother's Logitech keyboard with my old IBM KB-8923 it is immediately obvious that the IBM has more key travel, less friction and less wobling keys.
So far, I think this caused by the material of the key stem and the keyboard casing; the IBM keys seem to use a shinier material and their keystems are longer. This allows them to make more contact with the keyboard casing, making sure keys are pressed straight down.

As for the last one, the noise it makes: I think this must be caused by the material of the keycaps and the "springiness" of your rubber layer. The IBM keyboard I talked about sure clatters if you lift your fingers off the keys and let the key stem's clip hit the keyboard casing. The Logitech had less return force, hence it didn't make so much sound in that aspect.

Ok, cool!  Thanks for the info.  With this one it's not that it necessarily feels 'new' though, it's just always felt 'somewhat used' if you know what I mean haha.

Yes. You press the key cap which compresses the rubber dome. Under the dome, compressed air then escapes in the form of a "fart". A leprechaun living in the switch receives this fart, and this causes him to pull a lever for relief. The lever is also linked to an electrical circuit, and a connection is made. The lifetime depends on the type of leprechaun being used. The Japanese ones tend to last a little longer.

Japanese leprechauns?  Are they higher quality(better lever-pulling skills) in the Japanese ones?  I'm sure in some of the american 'boards they only have one leprechaun that runs around and must pull all the switches whereas the Japanese ones have one leprechaun per key.  That's why they're so much more expensive.