How to Test For Plastic Compostion Using IBM Spacebar As Example

[keyb_gr]

Was the spacebar under test worn shiny? Doesn't take much in my experience. Even the one in my main M is, which was almost unused when I got it 8 or 9 years ago. Now I don't write extremely much by any stretch, being neither a writer or typist nor a programmer. PBT should be tougher than that. Frequently-used keys like E or N have become smoother but are far from having lost their texture.

[keyb_gr]

Looks like further analysis will need to be carried out on a Greenock M spacebar in the future. I have a hunch that those are ABS.

[keyboardlover]

The things your wife lets you use the good kitchenware for...

[False_Dmitry_II]

Looks like further analysis will need to be carried out on a Greenock M spacebar in the future. I have a hunch that those are ABS.

Well, that would explain why mine warped a little bit. If anybody wants to send me a good model m spacebar, I'll do all the tests to it instead of trying to save it (it's not unusable yet).

I can say that it looks like all my space invader keys including spacebar are pbt. When I'm done with this set I'll do some pictures and make a rit thread.

[False_Dmitry_II]

Yeah. But not fun to find out while doing this. I was pretty sure all model m keys were safe to boil, so the less than that needed for rit should be fine. At least the space invaders don't seem to care. Now the only problem (with this in general) is that I was trying for a color that required a mix of two types of rit. I will never do that again, because it isn't doing it right.

[Findecanor]

A few months ago, I got a Cherry Corp black double-shot ABS set from a G80-11800. The space bar, however had the text ">PBT<" on the inside.
 ... today I did the acetone test, just to compare, and it failed! Cherry is lying about it being PBT.

[limmy]

Please edit incorrect information in OP on Topre sliders and slider housing.

TOPRE: The Topre sliders and plastic plate are ABS. This makes sense since the shell is marked ABS.

This is what I meant.
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(1) Upper keyboard housing(casing) of HHKB is marked as ABS in the casing. This also acts as slider housing of Topre switch used in HHKB.
(2) Slider housings of space bar sliders are not part of the upper keyboard housing (1), it is a separate piece inserted into a square hole of (1) -- This part fails acetone test (swiping with acetone left a mark) and seems to be ABS plastic.
(3) The slider of Topre key switch : this part passes acetone test. I used KG8 on this before it works fine although the lubricating effect wore off quite quickly. This part feels pretty similar to Derlin and it seems to be coated with some kind of lubricant. (The coat is hard and it doesn't come off by scratching with my finger nail. I didn't attempt to wash it. However, it gets scratched when used. Sliders from my 5-year-old HHKB are all scratched and don't feel as slippery as like-new HHKB and it lost some its slickness.)
(4) I placed adhesive silicone pad on the rubber that absorbs shocks from space bar for additional shock absorption. I like it so far.

My question here was whether slider housing of Realforce keyboard is made of ABS plastic. I explained here why this matters.

My question in more clear form is..
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Image from here

[limmy]

My question here was whether slider housing of Realforce keyboard is made of ABS plastic. I explained here why this matters.

My question in more clear form is..
(Attachment Link) 45344[/ATTACH]
Image from here

It is ABS plastic according to acetone swipe test. Since ABS plastics are not very good material for sliding surfaces due to its high coefficient of friction and high wear rate, Topre lubes the sliders to reduce friction and to add smooth feel.

Here is a picture showing a Topre slider that is relatively new.
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You can see thin film of what looks like grease. It is not sticky at all, so I am assuming it is not regular grease.

You can see more clearly in comparison between old and new sliders.
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The photo of the old slider show
1. visible scratches near the bottom of the cylinder and
2. its original shiny texture without lube being present.