Making Keyboard Membranes

[questarian]

I'm looking to make some keyboard membranes similar to the replacement that are available for the ZX 81's Spectrums. Does anyone have any advice, or the name of a good company to consider?
-John-

[gammaray]

I am working on this without using mass production molds... the reason was to make membranes that had no keyboard labels that could be customized.

Otherwise use Retroradionics for replacement membranes.

Charles

[1024MAK]

I use membranes supplied by RWAP from SellMyRetro. Good quality and good support

Mark

[questarian]

I was actually looking to see if anyone had any information about, or experience with, making membranes... I have a number of retro machines for which no one's producing replacements, so I'm doing some research to see how feasible it would be to do runs of them.

-John-

[RWAP]

I am working on this without using mass production molds... the reason was to make membranes that had no keyboard labels that could be customized.

Otherwise use Retroradionics for replacement membranes.

Charles

Charles - I am actually going to have a short production run of ZX81 membranes with a blank (black) thin top layer, so that it is easier to use with one of the custom overlays from Tynemouth Software

[RWAP]

I was actually looking to see if anyone had any information about, or experience with, making membranes... I have a number of retro machines for which no one's producing replacements, so I'm doing some research to see how feasible it would be to do runs of them.

-John-

I have quite extensive experience of working with keyboard manufacturers and have invested large amounts in getting membranes made over the years.

It depends on where you live to some extent - I have experience with manufacturers in the Czech Republic, Poland and the UK (the latter is my preferred supplier). Djordje (Retroradionics) uses a factory in China - although I am always dubious as to what he must be promising them, because the Chinese factories never seem to have any interest in an order less than 10,000 !

Cost issues are based on 3 main factors:
a) Initial graphics work and layout for the tooling (expect to pay between £150-£450 plus tax for this)
b) The size and complexity of the membrane being produced
c) The numbers of membranes being ordered - as you do benefit from bulk discount; although you also want to offset the initial tooling costs through the membrane. I have found that a minimum run of 50 membranes is just about feasible using my UK supplier.

Taxation and shipping of course

Why not list which machines you have and we can try to see how much interest there might be....

[gammaray]

I was thinking he was asking about the "rubber membranes". Is that what they are being called? As opposed to the "circuit membranes".

If he means rubber keys, I am going to taken resin and silicone to make a mold and production of new ones. Very difficult... because of tiny spaces...

Maybe injection is only way.

[1024MAK]

The rubber keys (like on the ZX Spectrum, TS1500 etc.) are normally known as keyboard/ keypad mats.
Membrane normally refers to the multilayer plastic/metal film part that contains the electrical conductors and contacts. In the case of the ZX81 (for example) this also includes a “printed” top layer with the keyboard layout.

Mark

[gammaray]

I missed again.

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[questarian]

It stared out as a conversation about replacing TRS80 CoCo membranes, and then branched into other old machines like the Mattel Aquarius. I'm not sure there's a huge demand, as someone had looked into it and was saying he couldn't offer them for less the $60 USD.

I did run into one low cost alternative someone came up with that I hadn't thought of, which is using foil covered kapton sheets and chemically etching them like circuit boards.

-John-