Hrmmm I wonder if this is going to be effective inside a CA66. I’ve heard those are fairly hollow so not sure if it the PCB will actually make contact with sheet itself. Anyone have any thoughts here?
@Manofinterests I’m already in for 2 12x12 sheets, but I have at least 3 65% boards to cover, so I’m thinking of picking up some more since I don’t want to be left wanting and I may also just fuck some up. If invoicing starts tonight, should I just fill out another form for any additional sheets I’d like?
Even though I already like the sound of my preonic, I’m starting to wonder how this would sound in there.
I’m not sure I fully understand why you’d want a thicker sheet for a 1.5mm plate. How does plate thickness affect the amount of space available between the plate and the PCB?
Are you still sending out the invoices? I ordered 1 - 12"x12" sheet, but haven’t received an invoice for it yet. Now I’m wondering if I gave you the wrong email address since I used auto fill while filling the form out?
If you want to add more sheets, just let me know if you haven’t received an invoice yet. If you have, PM me your invoice number and I’ll add it to your invoice.
The context for this is for a sheet that would be put out for switches and be placed under the plate but above the PCB. If a plate is 1.5mm, that would leave 3mm clearance. A 0.1" thick sheet is only 2.54mm, so I’d want it just a tiny bit thicker to ensure the plate/PCB make contact with the sorbathane.
I did half last night and will do the last half tonight. If you haven’t received an invoice yet, you should today
Yeah still no invoice, I don’t have the loot to add anymore sheets but do still want the 1 - 12"x12" sheet. Should I fill the order form out again or could you just invoice me on PP? My PP email is rob27shred@gmail.com if that is possible. Thanks for the quick reply bud!
Edit: Huey, ignore my question about filling out the order form again. I just seen you said you’re about halfway through invoicing. When you do get to mine, if the PP address is rob27shred@live that is wrong. My gmail address above is what I use for PP. Thanks again, you rock man!
FWIW, during a build a couple of days ago I tried using strips of 0.188" thick Sorbothane between the plate and PCB, and found this to still be too much contact; it felt like too much pressure to bring the switch bottoms into contact with the PCB. I ended up thinning some of the strips with scissors to reduce the thickness by about a third, which, as you might imagine, was not exactly a precise operation. But it was close enough to get meaningful sound dampening. This experience got me wondering what the ‘ideal’ thickness might be for this application.
Working from the Cherry MX specs, there should be at most 3.5mm (0.138") of clearance between the bottom of a 1.5mm plate and the PCB. There are 0.125" sheets that appear on Amazon, but I’m not sure that’s quite thick enough to make good contact, and while I don’t have a good set of calipers, a quick straightedge measurement also suggests 0.125" isn’t quite enough.
Going deeper into the rabbit hole, this engineering guide suggests that a deflection of 10-20% is good for dampening with shape factors between 0.3-1.0. The shape factor is the ratio of loaded (dampened) surface area to unloaded surface area. As an approximation to the total surface area of a 60% plate, the dimensions of a GH60 PCB are 285mm x 94.6mm, which gives us a surface area of 41.8 sq in. As an approximation to unloaded surface area, we can use the combined footprint of 65 switches, which is 0.61" x 0.61" x 65 = 24.2 sq in. Loaded = total - unloaded = 41.8 - 24.2 = 17.6. This yields a shape factor of 17.6 / 24.2 = 0.72. So, 10-20% deflection on a thickness of 0.138" suggests we want the Sorbothane filling for our plate/PCB sandwich to be somewhere in the 0.151"-0.166" range.
All of which is to say - at the moment, I’m less excited than I originally was about 0.18" precut plate/PCB sheets, but more excited about something like 0.155", assuming sheets of that thickness are feasible from both manufacturing and pricing perspectives.
Great write up, I’ve been speaking to the manu. about my plans for the future rounds and are still working back and forth about my plans with them.
What a lot of it comes down to is the pricing to be honest. I already know the quote to have the appropriate thickness of precut sheets, and it’s over $100 per sheet if you want it to be cut out per switch. I don’t think that’s a worthwhile value for anyone in the community to be perfectly honest.
I’m trying to work with them on an ‘effective enough, but affordable enough’ solution with them, and right now what I’m working on is overcoming the failure rates for the thickness/size/cutting. Obviously I don’t think a single person here should spend over $100 for a sheet precut for a 60% (Sorbathane plates anyone?), but I’m working on it.
I’ll take what you said in mind (I have maths of my own to work out), and hopefully for R2 I can have some exciting exclusive products to share with you all
For right now, I’m just working on making sure R1 production and shipping goes smoothly hehe.
Yup, totally get it - arguably I should have written this up in a different thread, but I remembered the subject of thickness coming up here, and I got excited. Ha!
Back to your regularly scheduled program. Thanks again for the push on R1!
Not sure what was the price but are you planning offering any sorbothane sheet with custom cut?
I like sorbothane between plate and pcb (where i think it works the best, compressed as hell), while in the case it doesn’t do much unless it’s compressed (small spaces or thicker layer of sorbothane). Would be really cool to have it precut.
I plan on it for R2. Right now I’m working with the manu to make sure R1 goes smoothly (should be shipping to me at the end of the month). I’m still in talks with them for my desires for future custom products to offer in R2.
I’ll keep everyone in the loop for what’ll be released in the future
