[Help] Ways to make a cheap case feel/sound more sturdy?

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ZedTheMan

[Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by ZedTheMan » 14 Jan 2019, 19:31

Hello DT!

Today I come to you with a question: what materials would be best to making a cheap plastic case seem less cheap? Of note, I'm using an OEMMAX MAC-105 with Alps SKCM Blue switches, and it is based as an AEK clone VERY similar to the Ortek-105. My main problem is that the keyboard creaks a lot and has a lot of flex. I tried filling the keyboard with a small thin pillowcase underneath the PCB, and this actually worked pretty well at reducing the creaking and made typing feel more sturdy, but unfortunately the seams on the side of the board were noticably spread apart by this and so I do not wish to damage it. There is a lot of open space between the plastic and PCB. This I wish to fill without stretching the board. Any recommendations?

Anything to make it feel heavier also is appreciated. I will post pictures later when I have them available.

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TheInverseKey

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by TheInverseKey » 14 Jan 2019, 19:49

I found that craft foam like the sheets used when you replace the IBM Model F foam is the best for the price.

Findecanor

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by Findecanor » 14 Jan 2019, 20:11

I have seen mods of more modern keyboards with sheets of bitumen put inside gaps. You should find it in auto parts stores, as they are used for sound-absorption in cars. They come in different thicknesses and could also be self-adhesive.

Electrical tape on resting-surfaces might reduce some creaking.

You could also reinforce the inside of the plastic case to make it more rigid. The best method to reinforce it would probably be to make it thicker by gluing on strips of ABS or some other polystrene-blend onto flat surfaces on the inside. Solvent-based "plastic model" glue for plastic would partly melt the pieces together for a strong bond. You could use small expensive sheets from a plastic model store, cut pieces of cases from other keyboards ... or so I've heard has been available at Home Depot in USA: pieces of a "For Sale"-sign that is supposedly made of ABS.
Care must be taken though so that you don't disturb the fit. If you make an error, ABS could be ground down with a Dremel with a routing bit at slow speed.
The best way to cut ABS sheet into smaller angular pieces is the "score-and-snap" method: there should be many videos about it on Youtube. Otherwise, a hack-saw or larger "razor saw" and a flat file are good tools for plastic.
I just noticed that coincidentally, this picture of my (rebranded) OEMMAX/Ortek-105 happens to also show my yellow "scoring knife": a hooked knife made for scoring plastic: The edge is on the reverse: You pull the knife towards you along a metal ruler. Most people use a box cutter but it is not as easy and safe to use.

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ZedTheMan

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by ZedTheMan » 14 Jan 2019, 21:18

Findecanor wrote:
14 Jan 2019, 20:11
I have seen mods of more modern keyboards with sheets of bitumen put inside gaps. You should find it in auto parts stores, as they are used for sound-absorption in cars. They come in different thicknesses and could also be self-adhesive.

Electrical tape on resting-surfaces might reduce some creaking.

You could also reinforce the inside of the plastic case to make it more rigid. The best method to reinforce it would probably be to make it thicker by gluing on strips of ABS or some other polystrene-blend onto flat surfaces on the inside. Solvent-based "plastic model" glue for plastic would partly melt the pieces together for a strong bond. You could use small expensive sheets from a plastic model store, cut pieces of cases from other keyboards ... or so I've heard has been available at Home Depot in USA: pieces of a "For Sale"-sign that is supposedly made of ABS.
Care must be taken though so that you don't disturb the fit. If you make an error, ABS could be ground down with a Dremel with a routing bit at slow speed.
The best way to cut ABS sheet into smaller angular pieces is the "score-and-snap" method: there should be many videos about it on Youtube. Otherwise, a hack-saw or larger "razor saw" and a flat file are good tools for plastic.
I just noticed that coincidentally, this picture of my (rebranded) OEMMAX/Ortek-105 happens to also show my yellow "scoring knife": a hooked knife made for scoring plastic: The edge is on the reverse: You pull the knife towards you along a metal ruler. Most people use a box cutter but it is not as easy and safe to use.
Thanks for the detailed response! I'm going to start with the removable modifications, IE, the bitumen and electrical tape, and see how that goes. If I still want more I do actually have some model glue for this purpose and know where to get ABS sheets.

Though, one follow-up, what exactly do you mean by resting-surfaces for the electrical tape?

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fohat
Elder Messenger

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by fohat » 15 Jan 2019, 00:46

Some people have simply pressed art-style modeling clay into the case to add weight and dampen the odd vibrations.

Might be a bit of a chore to scrape/wipe/wash out if you don't like it.

Personally, I have used felt fabric or "waffle" rubber sheets laid flat and/or rolled into cylinders of the proper volume to fill the voids.

Findecanor

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by Findecanor » 15 Jan 2019, 09:49

ZedTheMan wrote:
14 Jan 2019, 21:18
Though, one follow-up, what exactly do you mean by resting-surfaces for the electrical tape?
I'm sorry, I meant surfaces where a PCB or plate is touching plastic. The tape would reduce any rattling sound.

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ZedTheMan

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by ZedTheMan » 15 Jan 2019, 23:25

Thanks! That did help a bit with creaking! Bitumen is expensive, so for now I am just using a cut up pillowcase.

andrewjoy

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by andrewjoy » Yesterday, 14:27

I put in quite thin soft foam but several layers of it , use the case fixings themselves to slightly compress the foam So your making a sandwich between the PCB and case. This helps quite a bit !

The foam stops the echo inside the case and the fact the foam is pushing on the case reduces movement , any sounds that are made will also be better absorbed .

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Hypersphere

Re: [Help] Ways to make a cheap case feel/sound more sturdy?

Unread post by Hypersphere » Yesterday, 17:33

All the above are excellent suggestions. I especially favor the "art foam" or "craft foam" available from Michael's and probably other online sources. It is inexpensive and very easy to work with. I use light colors so that I can draw cutting guides with a ballpoint pen. It cuts easily with scissors. For keyboards that have reinforcing struts or ridges with contact points for the PCB, I cut the foam into strips and use double-sided sticky tape to secure the strips in place between the ridges.

I've also tried covering the ridges and contact points with foam, but this tends to create too much pressure, causing the case seams to bulge open when the case is put back together.

Most keyboard cases are tapered, with the narrowest part near the bottom (spacebar), so fewer foam strips are needed in the narrow end than in the top end.

Edit: Sometime, I would like to try some materials that have been specifically designed to absorb vibrations to serve as acoustic isolators. I did once try some sorbothane bumpers as keyboard legs, but this material contains lots of liquid plasticizer, which oozes out of the plastic creating a bit of a mess.

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