VOGONS


First post, by bristlehog

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I bought a mint condition IBM Model M keyboard. It's nearly perfect save for the spacebar button that is badly yellowed and has some scratches. What can I do about it? Can a spacebar button be ordered separately from anywhere? Or should I try and restore the button color by some magical reagent? Or, anybody here has a faulty Model M for parts?

From what I can judge this is an UK keyboard with large Enter key.

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Reply 1 of 15, by firage

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I replaced a few missing or worn keycaps and a yellowed spacebar on mine with parts ordered from ClickyKeyboards. The shipping cost a fortune, though.

I've used 20% hydrogen peroxide to bleach other yellowed plastic parts before. It would probably work.

My big-red-switch 486

Reply 3 of 15, by PCBONEZ

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firage wrote:

I've used 20% hydrogen peroxide to bleach other yellowed plastic parts before. It would probably work.

+1 hydrogen peroxide
UV light helps the process so soak it in a tray in the sun if you can.
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They use hydrogen peroxide + UV to whiten yellowed plastics on RVs and boats although they add something to turn it into a paste.
Basically they smear the paste on, put it in the sun or under UV lights, and keep it damp. Takes a few days.
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For small parts a bath should be good enough.
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Reply 4 of 15, by Malvineous

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This is pretty much what Retr0brite is. I've had some mild success with their recipe, but finding peroxide strong enough was a bit of a challenge for me.

Reply 5 of 15, by PCBONEZ

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Yes that's the idea. And I've seen that page before.
I question how much actual science and chemistry went into their formulation though because something they say doesn't make sense to me.

a mixture of hydrogen peroxide, a small amount of an "Oxy" laundry booster

Well, the "Oxy" in that 'booster' is there because it has hydrogen peroxide in it.
So... They are adding hydrogen peroxide to hydrogen peroxide... Huh?
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Cosmetology supply places (hairdresser supply places) should have it in strengths up to 12% (as opposed to the drugstore strength of 3%).
The 12% is called V40 (or Volume 40) - V30 = 9%, V20 = 6%, V10 = 3% ... see how the naming system goes.
The problem for me is that in the US one has to have a Cosmetology License to buy at such places.
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GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.

Reply 6 of 15, by firage

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Mine came from the pharmacy. I've also seen 17.5% and 12% solutions sold as gardening supplies. The higher concentration would be better, and if anything I would assume the stuff is easier to get ahold of in Russia.

My big-red-switch 486

Reply 7 of 15, by Malvineous

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PCBONEZ wrote:
I question how much actual science and chemistry went into their formulation though because something they say doesn't make sens […]
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I question how much actual science and chemistry went into their formulation though because something they say doesn't make sense to me.

a mixture of hydrogen peroxide, a small amount of an "Oxy" laundry booster

Well, the "Oxy" in that 'booster' is there because it has hydrogen peroxide in it.
So... They are adding hydrogen peroxide to hydrogen peroxide... Huh?

They explain this on the website - actually the old archived one now:

A catalyst is a really useful thing to have, as its purpose is to make a reaction go quicker by reducing the amount of energy ne […]
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A catalyst is a really useful thing to have, as its purpose is to make a reaction go quicker by reducing the amount of energy needed to start it; in effect, this was the “go-faster stripes” we were looking for.

TAED reacts with perborates and percarbonates which are formulated into the laundry booster, to produce hydrogen peroxide in the wash; all we are doing is cutting out all of the chemical “middle men” and giving the TAED some hydrogen peroxide to work on directly.

The small amount of Oxy laundry booster on it's own isn't strong enough to generate enough peroxides in solution to do the job, so we are deliberately giving it some help by adding some hydrogen peroxide directly into the mixture. It is this, along with the UV light, that allows us to destabilise the Bromine / Oxygen bond, break it and and attach a Hydrogen atom to the Bromine, removing the yellowing. Cool, eh?

The best explanation that I have for what we are doing is this. We are breaking apart hydrogen peroxide (H2O2) into O, H and water (H2O). Water dissociates into H and OH naturally. We are taking the oxygen away from the bromine using TAED and UV light, then replacing it with a hydrogen. The removed O links up with the O from the broken up peroxide and becomes O2 and is given off as bubbles. The picture below from Tonyyeb shows this crazy but useful mechanism at work; the bubbles are caused by the reaction on the surface of the ABS plastic.

Reply 8 of 15, by bristlehog

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firage wrote:

I would assume the stuff is easier to get ahold of in Russia.

I think you're right, it's possible here to buy 35% and even 50% peroxide. But how do I take the spacebar key away without breaking anything?

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Reply 9 of 15, by firage

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No special trick to removing the spacebar, just a bit of pressure. It does have a stabilizer bar and a grounding wire clipped to it.

Take care handling the chemicals.

My big-red-switch 486

Reply 12 of 15, by nekurahoka

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zstandig wrote:

That's the place. Unicomp continues to manufacture the Model M. You can get a full set of replacement keys if you want. I just bought an Ultraclassic myself.

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Reply 13 of 15, by bristlehog

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Here's the patient:

model_m_preview.jpg

If I just order a SDL to USB cable, it won't work with USB, will it?

Hardware comparisons and game system requirements: https://technical.city

Reply 14 of 15, by nekurahoka

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I wouldn't think so. It has to be able to talk to the USB controller and an original model m won't be set up to. An active PS/2 to USB adapter might work though.

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