I really like that you used unconventional methods to build it. So much of what we see is basically the same old thing in a different color with slight layout deviations. I’m sure you learned a lot through the process. I hope you don’t mind a few questions about the construction and end results.
Thanks! That was exactly my goal.
Construction
Were you able to laminate all the layers in one step or did it require several?
I was able to do everything in one bag, with the top and botton half next to each other. I used a coated ceramic tile (600x600mm) as the base, so it end up being perfectly flat on the faces.
I did it with a dry process, as opposed to a wet-layup. The epoxy does not permeate the paper very well, and to try and counter this somewhat, I placed a layer of fiber glass on the bottom. This did not help too much, and the center of the bottom two layers did not get any epoxy. I fixed this afterwards by adding some epoxy. Next time I will definately opt for a wet-layup. It is a lot more messy, but I think it will work better.
Did you have to cut out the switch holes later or were they made before the glue up?
I made the cutouts beforehand. I used a chisel that I made the same width as the hole so that I could cut one edge in one go. I used 6 layers for the switchplate part, with each layer 0.3mm. Then I cut the holes in the bottom layer a bit bigger so that I end up with 1.5mm for the switches to click in. The process had limited success for a couple of reasons. First was that the paper would move, despite me giving the layers tabs that I used to glue them together for this part of the process. That meant that the final sizes were not as exact as I had hoped for. The second reason is that the peel ply I used while laminating was not pliable enough, so some excess resin would end up in the cutouts and that meant I had to break it off and file the holes clean again.
(I don't think I would be able to make the holes afterwards the material is really tough.)
Are there nuts on the underside or do the screws “bite” into the lower shell?
I drilled them 1.6mm and tapped them M2, so 75% thread. I don't expect the thread to be very strong - a bit weaker than a tapped PCB would be, so fingertip torque only for tightening.
How does the composite sand/grind/drill? Is it hard? Soft? Flakey? Gummy? Any challenges working it?
Very much like fiberglass/g10. Which is to say it gums up the belt easily, and also burns/burnishes/discolor relatively easily. And it also is not at all lung friendly - so I wore a decent respirator.
So for the shaping I used a 80 grit belt at very low speed, going to 150 and finishing with 320.
End results
How does the weight compare with a wood or acrylic Atreus?
Well, it is surprizingly light, and sturdy. This was one of the design goals. Make it travel friendly. The case is about 155g in itself. Total coming in at 317g. This is my first Atreus, so I cannot really compare it, but since it does not have the top layer, and the material should be less dense than acrylic or plywood, I believe it is lighter and more sturdy.
Do the switches sound and feel any different in the Papyrus compared to other keyboards?
This was also a surprize to me. They sound unlike anything I have ever heard. It is hard to explain. I would have to make a recording to illustrate. I also put double orings on the caps. Overall it feels tight - that is the best way I could describe it. Tight, but in a very pleasing sense. And the sound is a very high pitched click. About half-way between how a mounted blue switch sounds and how a bare blue switch sounds when you hold in in your hand.
What do you like and dislike about the Papyrus, and in hindsight, what would you have done differently?
Thanks for sharing your project with us.
I expected to make a "novelty" keyboard - something that would not get much use, but this is so pleasant to type on. It is my first board with blue switches, but from experiences with other blue swidch boards, I was not expecting to like it. So I am very happy. The process was much more time consuming than I had hoped, so the one thing I will change is to have the paper laser cut before lamination.
I do think I will do this again, and soon. Next up will be a split something. Something like a (modified) Redox or Minidox or split Atreus. It will have either 50 or 62 keys.