Retro’s Rubbery Curse

Many retro computing enthusiasts have to deal with the headaches of decayed rubber and plastics. Here’s some advice from museum professionals and lab members.

By Yuri Litvinenko

Today in Tedium: I would’ve loved to claim I was targeted by Big Rubber while working on this piece; alas, it was nothing more than a chemical process. It all started with an attempt to restore an early-1990s Macintosh, during which I discovered that many of those Macs came with hard drives which turn faulty due to a degrading rubber dampener. A bit later, the rubberized sides of my vintage HP iPAQ handheld were discovered to be cracked. Newer devices were prone to degradation, too: this Christmas, I have inadvertently gifted a Nixon watch with a soft-touch coating which turned oily and sticky. With rubber decay being so widespread, is there some advice which museum professionals and people in academia can share? Let’s find out. — Yuri @ Tedium

Today’s GIF comes from one of many YouTube tutorials on dissolving sticky rubber coating on consumer electronics. A reasonable solution for household needs, it’s—as we‘ll see further—frowned upon by preservation professionals.

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Dissolving an old floppy drive motor wheel from a 1980 HP-85 computer. (Dennis van Zuijlekom/Flickr)

Institutional research into rubber degradation spans decades

Mesoamerican people processed rubber thousands of years ago, and further experimentation by Europeans and Americans led to an explosion of applications in the 19th century. Conservators hence had to devise ways to preserve rubber artifacts well before the modern enthusiast community was formed. In a 1988 study published in AICCM Bulletin, Sharon Blank of the Los Angeles County Museum of Art noted that rubber “is already posing problems in museums,” and listed several conservation practices. More research followed, with some compiled into guidelines—like the one by Canada’s heritage department—for use by accredited museum professionals.

Meanwhile, retrocomputing enthusiasts were forming their own takes on conservation which largely focused on the looks and ignored professional standards. Many people in the scene are still keen on de-yellowing old plastics with homemade peroxide-based gel (dubbed “retrobright”), a process which alters the structure of the material and does not prevent it from turning yellow again. The community is filled with stories which would make a museum curator gasp, such as when a high-profile YouTuber used a Dremel saw to open a rare computer.

What gives rubber and other elastic polymers their key capability—to return to an original form after being stretched or pushed—is their molecular structure. Building blocks which these polymers are made of are connected by carbon-carbon bonds to each other. When these chains are broken, rubber gets softer, Blank noted in his study; when they are linking together, the material gets more rigid and brittle.

“Sometimes it just becomes unpleasant to touch but doesn’t really leave much on your hands; other times, it’s a disgusting tar-like substance that melts like peanut butter as soon as you touch it and leaves hideous black streaks on your hands that are hard to wash off.”

— Gravis, a US-based pseudonymous vintage electronics enthusiast behind the Cathode Ray Dude YouTube channel. He notes from his experience that several mid- to late-2000s devices became sticky after a year or two of keeping them away outside a climate-controlled environment.

Rubbercare n95

That’s how bad a phone from 2007 can get. (Mobile Phone Museum)

Preservationists can’t completely stop rubber from degrading, either

Museums, especially ones which focus on consumer electronics, face the problem on a wider scale. Will Wood, content director of the newly opened Mobile Phone Museum, says they had to recycle some cell phones from their collections because “they are so sticky, and they are so disintegrated.” Registered in the UK, the museum lists over 3,500 devices including duplicates—and, per Wood’s estimates, “about 5 to 10 percent of our phones have some sort of cosmetic issues—with plastic, battery, that kind of thing.”

Plastic degradation can take other forms, too. Dr. libi rose striegl, a Media Archaeology Lab manager at the University of Colorado Boulder, tells that, in a semi-desert climate of the inland state, rubber tends to get hard and crumble.

“The age range on our collection is so wide that we encounter a lot of different rubber issues, but the thing that springs immediately to mind is our lie detector from the 1930s that had a lot of natural rubber components,” they say. Beyond getting rigid, these parts emit a distinct odor which striegl described like “the lingering smell you get several days after accidentally melting plastic, plus general mustiness/staleness.”

“Nothing can be done to halt this decay, but with care it can be slowed considerably,” says Adrian Page-Mitchell, collections officer at the Centre for Computing History in Cambridge, UK. Per the museum’s web site, it preserves over 800 vintage computers, as well as mobile phones, consoles, and memorabilia—about 24,000 items total.

In an email interview with 30pin, the curator advises keeping objects in a dry environment, as stable as possible temperature-wise. “Nothing will hurt an object more than being kept in a hot room, as it accelerates the gassing,” Page-Mitchell notes. He explains that all plastics and rubber emit gas, so items should be put in ventilated bags made of inert plastic and preferably left in the open. “If an object has to be kept in a box for space restrictions, remove it regularly and sit in out for an hour or two, separate all materials from each other,” he advises.

Rubbercare cable

A SCSI cable from the late 1980s, used to connect external hard drives to Macintosh computers. (Museums Victoria Collections)

Five components prone to rubber decay, and some ways to deal with it

  1. Belts, gaskets, washers and many other internal rubber elements—used in floppy drives or other motorized components—are easy to replace with modern parts, curators agree. striegl notes that vintage computers with built-in printers tend to take non-standard belts for their print drives, though.
  2. Cords and cables are, in striegl’s experience, covered in “the worst rubber I run into on a regular basis… always either rigid or sticky, always gross.” They note that rubber bands which some people use to wrap plastic around them decay as well. For that purpose, Page-Mitchell advises using museum-grade string. (He pointed at a Norfolk-based Preservation Equipment Ltd as the centre’s supplier.)
  3. Rubber feet were discovered by the Centre for Computing History to react to a wide variety of shelves, including those made of plastic, woodchip, and glass. “A project is underway to place all our computers that have them on inert Plastazote pads,” notes Page-Mitchell.
  4. Non-functional internal parts which have gone bad are better to be removed, thinks striegl—otherwise, they “might crumble and get in the way of proper functioning.”
  5. Hard drives with internal rubber components, like the one described here earlier, cannot be fixed without damaging them permanently, Page-Mitchell says. In cases of a faulty drive, he advises to keep the collection machine stored intact and use modern stand-ins—usually based on Raspberry Pi computers or Arduino micro-controllers—for the display one.

Rather than trying to fix devices which show considerable rubber decay, it’s better to focus on “preserving them in the state which they’re in and making sure they’re not getting any worse,” adds Wood—and his peers share the sentiment.

Page-Mitchell discourages any attempts to rework or clean the rubber: “No cleaning can take place, as it would only serve to destroy the object further, no detergents or soaps are ever used on the collection.”

Wood notes that, despite the museum’s desire to have every object in pristine condition, many of them only exist in a degrading one—and people do realize some exhibits were used daily. He admits the challenge is yet to be solved.

“We’ve almost kind of embraced that.”


Thanks again to Yuri for sharing this one with us; be sure to check out his website 30pin for more great stories like this!

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Yuri Litvinenko

Your time was just wasted by Yuri Litvinenko

Yuri Litvinenko is a media and telecom reporter at Kommersant, a Russian business newspaper, and was previously working as a news editor at Kommersant and Vedomosti. In his spare time, he maintains 30pin, an online magazine of consumer tech history.

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