Model F XT foam

Wazrach · 06 Oct 2018, 19:30

Hi guys, I'm looking to buy a foam mat cut to size and ready to use for my XT. I've tried making my own mats with different foam thicknesses, but I just can't do it right... I assemble the keyboard together and it feels inconsistent and sounds like crap. I'm really looking for some high quality foam that will not deaden the sound or ping. I'd happily settle for something like this: https://www.mcmaster.com/8647k102 if anyone has any. Thanks in advance!

fohat · 06 Oct 2018, 19:57

That is softer and thinner than I would recommend, but it may keep the sound loud.

Wazrach · 06 Oct 2018, 20:07

Ah, I meant 1/8", not 1/16

xxhellfirexx · 06 Oct 2018, 20:07

Try asking Orihalcon to see if he would make you some XT foam. I know he does for beamsprings.

Wazrach · 06 Oct 2018, 20:09

I did ask him about this a little while ago, and he said he no longer has the time to do it.

Wazrach · 06 Oct 2018, 20:10

I really enjoy making mats, but I just mess up everything I touch.

fohat · 06 Oct 2018, 22:30

People have used plastic packing sheets and all sorts of materials. I don't know what the slippery stuff (that is not closed cell foam) is called, but that might give you what you want.

Are you using a punch and doing it the way I did in my guide?

Wazrach · 06 Oct 2018, 22:41

I used a hole punch, yes. I realised the plate was bent when disassembling it again. This must have happened after I disassembled it the first time. I tried bending it inwards and putting the original foam mat in, but it still feels terrible and mushy and inconsistent. God I hate myself. It's going to feel like crap forever. It was fine until I started messing with it. Why can't I do anything right?

Wazrach · 06 Oct 2018, 22:58

Forget it. Foam isn't going to save this.

fohat · 07 Oct 2018, 00:58

Whoa! Bent the plate?

That is a serious hunk of metal. How in the heck could you even do it?

xxhellfirexx · 07 Oct 2018, 01:45

fohat wrote: Whoa! Bent the plate?

That is a serious hunk of metal. How in the heck could you even do it?

Maybe by applying too much pressure with the clamps while trying to separate the plates?

Wazrach · 07 Oct 2018, 11:27

It's obviously tried to straighten itself out along the middle. This has happened every single time I've opened a Model F. Seriously, what am I doing wrong? I had a lovely keyboard until I ruined it.

fohat · 07 Oct 2018, 15:36

As detailed in my guide, I straighten out the (usually) one tab that was bent over at the factory to keep the plates from sliding apart, then stand the inner assembly on end and gently tap one of the plates with a hammer until it slides a few mm and the tabs dis-engage from their slots, allowing all the pieces fall onto the table.

To re-assemble, I do the reverse, and, as soon as I have slid the plates together just far enough to engage the tabs, I stand it back on end and tap it down the rest of the way with a hammer.

Wazrach · 07 Oct 2018, 22:14

I know how to disassemble and reassemble these, although I really appreciate the detailed advice. I tend to use clamps with the XT, even with thin foam.

I was talking about the fact the barrel frame straightened itself out along the middle, so that it was no longer parallel with the backplate. I could feel a lot of wobble and sponginess in the center row, so I disassembled it yet again and tried to add curvature to the barrel frame with the spine of a book. I couldn't get it uniform like it was before, and it still feels spongy. The spacebar sounds quieter and has lost its presence, as well as its amusing ping sound.

I have some art foam coming tomorrow. I don't know how thick it is, but hopefully it will be thin enough to use in the keyboard. I will also try adding more curvature to the barrel frame, so that the foam may force it back into its natural position once assembled. If that doesn't work, then I really don't know what will. May as well sell it for parts.

Assembling it with thick art foam should be fun! I will be home alone for a week, so no help - just three spring clamps and my bare hands.

orihalcon · 08 Oct 2018, 05:33

It's not too uncommon for the center row to feel a bit looser than the other rows if thick enough foam isn't used. The way around that though is to just put a bit of extra foam on that row. Something like a thin 1/8" or so strip of the same foam that runs down the row to give it some added thickness only there, and there's no fancy cutting that needs to occur.

I do have some original IBM foam from 3178 blue switch model F's that is the non-degrading type, though the layout is different than the XT, the main block is pretty much the same and you can cut it and have it work on an XT. I've done this with several XT's and I think the results are pretty good. There is no rule that says the foam has to be one continuous sheet

Wazrach · 10 Oct 2018, 00:04

It doesn't just feel "a bit looser" unfortunately, it feels terrible - 10x worse than before I took it apart and put the new thicker art foam mat inside. The little alignment nubs that stick through the barrel frame are not uniform - they're just about poking through the middle of the barrel frame. I really don't know what to do, but I have a feeling a bolt mod is the only possibly thing I can do to save the keyboard... Really, really regret taking it apart to clean it in the first place. The key feel and sound is COMPLETELY ruined.