Dusty, brittle plastic

A buddy on Classcomp asked that I re-post something I posted there. I have never heard of this particular forum but was glad to know of it and glad to perhaps contribute.

Every time I mention it someone responds with horror, but WD40 has been a terrific tool for me, is indispensable. It was plastic that was mentioned in the Classicomp post, brittle plastic.

I can’t guarantee that a totally disintegrated plastic can be rejuvenated by any method, but I’ve had very good luck with dusty-surfaced plastics, ones easily scratched, ablative due to age. A coating of WD40 will be drunk-in by the plastic, pretty quickly at first, and subsequent applications more slowly, overnight. Repeating this until the plastic no longer drinks the WD will rejuvenate the Surface of a plastic, at least the sorts of plastics used in many computer cases, the Atari computers (all of them), the bezels of floppy disk drives, faceplates of IBM PC/XT and just about any computer with a plastic shell. If got to early, the results are remarkable.

Other uses I put it to are to wipe contacts, card-edges, and to clean contacts and switches. I use swabs to apply it to the guide rails of disk-drive headsleds, to restore all kinds of moving parts. To access points I cannot use a swab on I use a syringe filled with WD40 to make precise, very tiny applications. This is especially helpful with floppy drives, as their most common failure modes are mechanical or electronic failures of the cascade variety, caused by sticky mechanical. A good example of this, and common, is failed darlington drivers. They fail because the motors require more power to move than the designed maximums, putting strain on the drivers and frying them. you can replace the driver and blow it again pretty quickly, but if you lubricate the mechanism (once in 40 years is not too little!), it will take the load of of a working driver or allow a replacement to live, a fair chance at life anyway.

As for retrobite, which was mentioned in the email to me, I’ve used the souse method to brighten keys, but larger items are difficult to do. I’ve been using paint, which the plastic also really appreciates, it being oil-based after all.

Thanks for listening and I hope I’ve given someone a hand-up. I’ve been working on computers for 40 years now, have had at least one of pretty much everything from Acorn to Zorba, and would not steer you wrong.




Welcome Jeff! An interesting idea, and a new one for me. (I have heard, I think, in the field of mechanical calculators, that WD40 should not be used as a lubricant: light machine oil is the right stuff.)

Another slightly unexpected tactic I’ve heard of: mixing superglue with cornstarch makes for a quick-setting plastic filler. Plenty of videos out there about this.

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Thank you for this! The applications of WD40 are apparently endless. Sadly, it’s not available everywhere. (Does anyone know a replacement product in continental Europe? Correction/Update: As I just learned, it’s actually available.)

I’ve used superglue with baking powder to great success. Especially for reinforcing stressed case parts. (E.g., the tiny bridges of plastic that grab a tab, or, I’ve used it to mend the case of an Olivetti M-15. These are notorious for cracked rear edges, because of the stress exercised by the screws for fastening the display.) It’s also great everywhere, where the surfaces to mend are too tiny to produce a lasting bond, just produce a reinforcing layer covering and around the crack and it will be ready to withstand any kind of physical stress.


This is true. They make sewing machine oil for such purposes.

What makes WD40 a good thing for restoration work is that it is mostly an aromatic carrier, Naptha. The naptha carries a light oil with it into places gummed up with 40 year old factory-lubricants entropy has solidified. The naptha liquifies this mess an carries it away, leaving a very light sheen of very light oil where it has gone. I sometimes follow this process up with a coating of white lithium grease, on worm gears etcetera, high-friction areas which will consume the very light oil in wd40 quite quickly. So my main purpose is to free mechanisms and return them to proper operation prior to providing whatever additional lubrication is needed. In this role WD40 is more a cleaner than a lubricant. Oh!, another excellent use for it is removing labels from parts without harming the parts. It will dissolve the atrophied gum under old labels. I soak the label, peel off what I can, and then work the gum off with a fingernail. It might leave a clean spot, shaped like the label, because the label has protected the area from wear/fading/yellowing, but that cannot be avoided and is no fault of your work or tools.



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OH!, there is a very similar product, CRC 666, which may be more generally available in Europe than WD40.

Regarding lubrication, a variety of thin machine oil and more viscous lubricants for gear mechanisms (including special lubricants for conductive parts) can be found at model train suppliers. However, as always with niche markets, prices are probably not the best and you can probably find similar products for a fraction of the price asked.

Remember, WD stands for “water displacer.” For cleaning contacts and switches I would use a cleaner specifically made for it, such as tuner cleaner. (Sometimes it is referred to as control or contact cleaner.) For card slots and card edges I would use something like Caig DeoxIT. For floppy drive rails clean them first, then apply a light sewing machine oil with a Q-tip.

I don’t think I’ve ever used WD-40 near a computer, except as an experiment to get some more life out of a printer ribbon. (And it worked well enough.)

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