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PC case rust repair

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pinkdonut666

Experienced Member
Joined
Apr 18, 2019
Messages
195
Location
Alberta Canada
So recently I picked up a leading edge Model D that had been dumped off at a recycling center.

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As you can see the machine was in very sorry shape. I was able to get it completely functional hardware wise, but I really wanted to do something about the case.

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So I ground down the rusted areas with a 3M roloc disc on an air die grinder, there was actually alot of small bubbles that hid large rust patches underneath the paint.

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I used this Product to neutralize any of the rust that remained. It's basically just phosphoric acid & isopropyl alcohol. The phosphoric acid turns the Iron oxide to iron phosphate (black shale like) and stops it from spreading. I didn't wanna have it bubbling up again.

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and this is the somewhat finished product after a few coats of Rustolium 2X ivory Bisque spray paint. looks pretty good IMO.

now the question is whether or not I want to attempt to retr0brite the front bezel & keyboard. I'm going to leave it until the weather warms up at the very least (-20c here with 2feet of snow) so not ideal weather for retr0briting outside. But even then , not sure if i'm going to bother. The yellowing sorta gives this machine an aged charm. so I'm on the fence.

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(I didn't paint the black bezel in this photo i actually found a beige bezel that matched the floppy drive better.
 
You may just want to repaint the bezel in a water-based acrylic paint. That will seal it and help retard further degradation. Just mask off the badge.
 
T-R-A said:
Nice work on the cover. Personally, I'd just leave the bezels. In certain cases, retr0bright lost it's effectiveness in a rather short time (or you could paint those as well---as suggested above):

https://www.classic-computers.org.nz/blog/2013-01-15-retr0bright-only-temporary.htm
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Possibly could lose luster over time but not always. Seems to depend on the type of plastic. Honestly the front bezel is a small piece and would be easy to retrobright. I just bought a lamp to build my 3rd indoor retrobright cabinet. Its pretty easy at this point.
 
I've never Attempted to retr0brite anything before, and I have many "ripe" yellow computers lol

My concern was with the keyboard. I could paint the front of the case, but then they keyboard wouldn't match.

I really really don't like painting keyboards or game controllers. anything that your hands touch i've found paint does not react very well. The paint softens up and smudges in my experience. So I want to avoid even painting the keyboard bezel.

I don't mind the yellow, and I feel i'll probably leave it that way for now, and maybe in the summertime i'll experiment with the front bezel of the computer if i'm feeling adventurous
 
You did see the notice by the museum conservators rejecting the Retr0brite treatment--it apparently cause small cracks in the plastic surface. But hey, a Model D isn't as rare as a 2 cent Inverted Jenny...

On the other hand, a museum conservator is more interested in appearance, rather than actually trying to use the thing.

Paint resists handling very well, if it's the right type. Witness my F85:

F85_front.jpg


That's paint over high-density polyurethane foam.
 
If there's cracking perhaps they could be sealed up with the application of heat? Or a solvent dabbed on?

You can leave things out in the sun and rain to alleviate yellowing.

Repainting metal is easy. It's obtaining the gritty texture that's currently a mystery to me.

3rs edit. Maybe multiple gentler applications of retrobrite may rest in less or no cracking. A weaker solution iow.
 
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tipc said:
If there's cracking perhaps they could be sealed up with the application of heat? Or a solvent dabbed on?

You can leave things out in the sun and rain to alleviate yellowing.

Repainting metal is easy. It's obtaining the gritty texture that's currently a mystery to me.

3rs edit. Maybe multiple gentler applications of retrobrite may rest in less or no cracking. A weaker solution iow.
Click to expand...

There need to be more 3d imaging devices that can render these things into appropriate files for 3d printing... Retrobrite... not to retrobrite.. it doesnt matter they are at end of life.. decay is already set in.
 
VERAULT said:
There need to be more 3d imaging devices that can render these things into appropriate files for 3d printing... Retrobrite... not to retrobrite.. it doesnt matter they are at end of life.. decay is already set in.
Click to expand...

Plastic can be remelted. If you had the original dies, you could melt down a bezel, case or whatever, shoot it into the mold, and what came out would be like brand new. Certain plastics anyway. I was thinking likewise the cracked surfaces, I've never seen this but presumably the cracks are very small, could be "healed" by the reapplication of heat.
 
You first. When you succeed in preserving plastics, be sure to notify the Guggenheim and other museums with plastic artworks that desperately need preserving. The problem with a lot of old plastics is that binders have degraded and plasticizers have outgassed. 30-year old ABS is not particularly recyclable.
 
In general if it can be melted, it can be remelted. I imagine in cases if subatances are depleted, they can be replaced? No one is going to melt down computer case components, that wasn't the point. My thinking was surface defects can be smoothed over so to speak. Whether by application of heat or solvents.
 
Chuck(G) said:
You first. When you succeed in preserving plastics, be sure to notify the Guggenheim and other museums with plastic artworks that desperately need preserving. The problem with a lot of old plastics is that binders have degraded and plasticizers have outgassed. 30-year old ABS is not particularly recyclable.
Click to expand...

Yes i would imagine thats its no longer viable either.
 
Anyone with some of the late 80s self-destructing Apple gear might learn something. I tossed a perfectly good Apple color monitor because the case would spontaneously shed bits of itself with no one around. Come to think of it, I owned a Volvo turbobrick whose interior plastics did the same thing...
 
Has anyone else ever given serious thought to using vinyl dye as a better alternative solution to painting or retrobrighting? The biggest problem of course is colour matching the plastic but there are automotive paint shops I've found which offer this service.

I've only ever tried it with an off the shelf spray can brought from an automative store to paint a hard drive cover to match the original drive bay colour. To the naked eye it was almost a perfect match (see photo). Worked brillantly as unlike normal paint it's pretty hard to stuff up and once dry it will not scratch off due to the fact it seeps into the surface and effectively changes the colour of the plastic. I've always wondered since then if this would be a risk free way of retrobrighting/repainting without all the downsides to both methods.

IMG_20151010_135134.jpg
 
With what? Solvent? That turned the bits to crumbly granules. If you've followed my posts through the years, you'd know that I'm a big proponent of solvent cements in place of glue. Some stuff just doesn't have sufficient structural integrity after all of the volatiles have disappeared and the bonds start breaking.
 
Perhaps a solvent. As a precursor to actual melting some constituents may need to be added back in. I'm not claiming to be an expert, just putting stuff out there. In theory anything can be ground up and slathered onto something with a binder. Some modelmakers do this. A solvent is ideal as it reduces the plastic to goo then evaporates. But an adhesive could work also.

@Joe, never heard of vinyl dye. With paint though if you thin it to the consistency of milk nearly, oil based paints anyway, it goes on and adheres tightly to a surface, obscuring the surface minimally. Some colors vary in opaqueness though (that a word?). In some instances it may make more sense to blot or dab paint on.
 
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