Not old. Vintage.
I must admit, this chapter was not originally part of my plan. For a while, I had considered my restoration project complete:
All the damaged components were repaired .
. The computer was operational and usable .
. I had found the ideal furniture at Ikea to showcase and use the Macintosh, occupying minimal space in the house and thereby avoiding being kicked out by my wife .
at Ikea to showcase and use the Macintosh, occupying minimal space in the house . Additionally, I had just discovered the Floppy Emu, a floppy emulator that would enable me to explore all the software ever created for the Macintosh 128K without further financial strain.
So, what more could I have asked for? Yes, it’s true, the casing was still somewhat dirty and had yellowed over time, but wasn’t this a perfect reflection of its history and the character of this iconic machine?
For a while, I convinced myself of this romanticized view and thought it unnecessary to risk reopening and completely disassembling a Macintosh that had just begun working again, merely for cosmetic reasons. That was until my timeline started to be filled with articles and videos about retrobright, and a new doubt started to take root in my mind.
Retrobright
This mixture was developed by Dave Stevenson, an English chemist with a passion for retrocomputers 18. Its purpose is to restore the original color of ABS plastics 19, a material extensively used in the casings of various electronic devices over the past 50 years.
Stevenson hypothesized that the yellowing was not due to the ABS itself, but rather to bromine, an element added to ABS for its flame-retardant properties. When exposed to UV rays from the sun, bromine naturally tends to revert to its original brown color, thereby causing the entire plastic to yellow 20.
Label removal We save anything that could be damaged during washing.
Washing the case Water, soap and elbow oil.
Washing the case Water, soap and elbow oil.
Retrobright Gel ready to spread.
Retrobright Gel coated on plastics and exposed to the sun.
Disaster White spots and streaks on the surface.
Disaster White spots and streaks on the surface.
Retrobright #2 Let’s try to fix with controlled artificial light.
The Retrobright formula was made public in 2008 and consists of a blend of high-concentration hydrogen peroxide (10%–15%), active oxygen, and thickeners to create a spreadable product.
The outcome of this formula is a gel. When applied to plastics and exposed to UV rays, it is intended to return the oxygen molecule to the bromine, thereby it should reverse the yellowing process.
I use the conditional tense because, since 2008, the community of enthusiasts has continuously experimented with and modified the compound, leading to the creation of numerous variations 21. Over the years, there have been documented instances of failures and long-term effects on plastics. These findings have raised questions about both the role of bromine and UV rays in the yellowing process, as well as the effectiveness and safety of the mixture and method itself 22.
I confess that despite the wealth of information available for research, my complete lack of knowledge in chemistry, combined with the overwhelming number of highly positive reviews, led me to overlook any potential risks or negative aspects. I wanted had to try!
Everything under control
For my experiment, I selected one of the brightest (and hottest) days of the year, considering the significance of UV rays in the process. Prior to starting, I removed any labels, logos, or tags that might get damaged 20. Each piece of plastic was thoroughly washed to eliminate any dirt or dust residue from the surface 21-22.
I prepared about a liter of Retrobright and gradually transferred it to a basin for application on each plastic piece 23. To prevent the mixture from evaporating quickly under the sun, I followed several tutorial suggestions and covered each piece with a film 24. In hindsight, this was the first of many mistakes .
After approximately 2 hours of exposure, I decided to check the results of this initial attempt, and that’s when I encountered my first major setback. Despite the film covering, the gel had almost entirely evaporated and had done so unevenly, following the creases of the film. The outcome was disheartening. The gel had only managed to lighten certain areas of the plastic, creating stains and streaks across all surfaces 25-26.
Panic
Following that setback, I embarked on a series of hasty attempts, hoping that another application might even out the coloration. Initially, I repeated the process without the film, refreshing the mixture every 20 minutes throughout an entire morning to prevent evaporation. Subsequently, I replicated the procedure in an environment with controlled UV light 27.
In both instances, I managed only to lighten the different areas proportionally. The darker parts became lighter, but so did the already light areas, which further intensified and essentially preserved the initial streaks.
Plan B
It dawned on me that any further attempts would be futile, only serving to further degrade plastics already stressed by various treatments. This realization was followed by a few weeks of discouragement, during which I hesitantly returned to eBay to browse through auctions for exorbitantly priced spare parts. Eventually, I settled on the only viable option: painting the plastics.
Interestingly, Apple had abandoned the practice of painting plastics with the introduction of the Macintosh. They believed that using ABS plastic already colored appropriately would prevent the natural variation in paint color when exposed to sunlight. Ironically, the opposite occurred: all the painted plastics from earlier models withstood the test of time much better 23.
Plastic painting Professional back plastic painting.
Plastic painting Professional plastic painting on the front, keyboard and mouse.
Before yellowing state before retrobrighting and repainting.
After Yellowing status after repainting.
This time, thank God, I decided it was best to directly consult professionals. My sole task was to find the correct color reference 24. I entrusted the job to a local body shop specializing in plastic painting, and they executed the work with great precision and care 28-29.
What can I say? The Macintosh had not only become “presentable” but had almost turned into a showpiece 31, and I had finally run out of ways to potentially compromise its safety again.
The restoration could at last be considered complete. Just in time to celebrate the 40th anniversary of the Mac!