Plate made of PCB-material? Crazy or sound?

[Eszett]

I'm prototyping on my custom DIY keyboard since a few years and up to now I ordered plates from a local steel cutting company, which is pretty expensive. To save money I came to the idea that while ordering my PCBs from China, I could order with the same shipment a pseudo-PCB which is cut as a plate, but made out of PCB material? Does that work, what do you think?
1) Standard thickness of PCBs is 1.6mm that matches the thickness a plate should have, isn't it?
2) Is the material maybe too soft to type on?
3) My rough calc is, that for a 60% steel plate I usually pay around 40 Euro (incl. shipping) to my local steel cutting company. But for a PCB of that size, it's rather ~15 Euro, so less than half the price. (shipping doesn't matter, since I order my real - electrical - PCB from the same manufacturer anyways).

[King Icewind]

It works fine but not as good as a metal plate in my opinion.

[nevin]

yes, all good. i actually prefer FR4 plates to metal

and depending on size, you can order it all as one piece like this numberpad

https://spacecat.design/collections/pcbs-cases-kits/products/soyuz-number-pad-kit

some other examples
https://spacecat.design/collections/pcbs-cases-kits/products/gherkin-kit
https://spacecat.design/collections/pcbs-cases-kits/products/laplace-40-staggered-kits
keeb.io has built a whole brand around the spaced FR4 plate idea. offering all sizes & shapes of mainly split keyboards.
and there are many, many more that use the spaced FR4 plate design

[Eszett]

nevin, I guess you are using 1.6mm? Can you tell why preferring FR4 to metal? Does it feel softer than metal? Is there a huge gain in stiffness switching from 1.6mm FR4 to 2.0mm FR4? My PCB manufacturer wants like ~30€ more if 2.0mm is chosen instead of standard 1.6mm, that is pretty prohibitive.

[nevin]

mainly the sound. FR4 doesn't ping/ring like metal does.
nope. 1.6 is the standard. if you go thicker the switches won't "click" into place. just measured the one i'm typing on and plate is coming in about 1.53mm (cheap caliper)
if you want it stiffer, just add more supports. m2 brass standoffs & screws are typical hardware used

another note: if making a new plate, use the cutouts that support switchtop opening or the alp/mx cutout (also supports switchtop opening) that way you can basically change your switches (all but bottom housing) without desoldering anything

[Eszett]

Thanks, man. Only downside is you can't powder coat that FR4 stuff, isn't it. Maybe some acrylic laquer sticks to it.

[nevin]

you could paint it, it's just fiberglass. nothing fancy needed. just give it a good sanding so the paint has something to stick to (get rid of the shine).
the latest thing is for manufacturers to paint the pcbs black or some other color.

[Eszett]

Ye, gettin a matching PCB color from the manufacturer is the more clean solution!

[nevin]

i liked it better when the fiberglass was colored.... transparent, red, blue, amber, etc AND you could still see the traces. they weren't buried under a layer of paint.

[Rayndalf]

i liked it better when the fiberglass was colored.... transparent, red, blue, amber, etc AND you could still see the traces. they weren't buried under a layer of paint.

Old PCBs that are semi transparent are the best. When I replace the PCB in an old keyboard I usually hold on to the old one just because of how cool they look. Older DIY (made in someone's oven?) feel so special.

[nevin]

Older DIY (made in someone's oven?) feel so special.

yeah, the ones with hand drawn traces! super cool
it's the same etching process as ones made now, was just done by hand instead of computers and automated processes.

[piit79]

But for a PCB of that size, it's rather ~15 Euro, so less than half the price.

Is it a very large board? The PCB plates I order from JLCPCB turn out much cheaper, less than half that (MOQ 5 though, or even 10 as for lower quantities they sometims charge me extra for excessive milling).

As a bonus, if you wanted a really fancy plate, you could use the copper areas for aesthetic purposes, like they did with the Polaris plate: https://i.imgur.com/S2gslFr.jpg

[Eszett]

I do order from JLCPCB too. My plate would be ~31 cm x 13 cm. IIRC guess there is a huge price difference if something is larger or smaller than 30 cm ... not sure though.