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Need advice on paint stripper that is safe on plastic. Need to fix what a hack ruined

VERAULT

VERAULT

Veteran Member
Joined
Jan 30, 2012
Messages
8,552
Location
Connecticut, USA
Ok I am pissed, really pissed. I bought an Apple IIgs earlier this year and put it in the basement till I could get to restoring it. Today was that day. I recapped the main board and then thought I would tackle and clean up the case followed by a retrobright. The machine was blotchy yellow but I didn't think anything of it at first. Then while trying to polish away stains I noticed they got worse!

Long and short of it, the idiot painted the entire case various shades of yellow! Its long past my ability to file a claim which I would have done from the get go. Who paints a computer case to look old and yellowed?!

So I am determined to strip the paint, properly clean the case and retrobright it. However I don't know a thing about stripping paint, especially on delicate plastics. Can someone please recommend a stripper solution I cant paint on and strip away this nasty yellow paint without melting the plastic?
 
don't know really. But ammonia removes a lot of paint, and pretty quick. Perhaps dunk it in a container of strait ammonia, but don't leave it in there for long. Rinse immediately along with scrubbing with a scrubby sponge thing. Initially try dunking for 30 seconds. Most metal computer case paint can be removed, a lot of it anyway, by draping the case with newspaper and pouring on some ammonia. Just be careful though as I don't know what it does to plastic if left in it for long.
 
One of my hobbies is restoring Tonka and Buddy L trucks.

We've used brake cleaner to remove paint from the plastic parts without harming the plastic. But it's very dependant on what kind of paint used.

The last paint that I had to remove from the plastic wheels came off with soap and hot water.
 
I have a spare IIgs case. It has some damage, but fixing the damage with some bondo and wire and touch-up painting it might be easier than stripping the paint off what you have. Or you may at least be able to use the top cover (it has some damage too, but would be the easiest to fix).

It was a victim of poor packing from an ebay seller. Let me know if you are interested and I'll snap some photos sometime tonight when I get tired of playing Wasteland 3. :3

That is interesting that you had to recap it. I've seen a billion Macs with bad capacitors, I've never had to touch any of my Apple IIs (including 4 IIgs boards). The mainboards I mean. I have had a little trouble with one power supply, but only one.
 
Standard grade DOT 3 brake fluid has worked extremely well for me in the past on Apple plastics and I trust it enough I used it to strip my rattlecanned Lisa with EXTREMELY positive results pulling black paint even out of the texture without needing to scrub. It gets under the paint and lifts it off the plastic which it can't penetrate.
The only caveat is the surfaces must be kept moist either by laying soaked rags over the painted surfaces or immersing it. By the way, brake fluid is not environmentally friendly, but it's hygroscopic so it washes off with soap and water and leaves a nongreasy surface.
 
Citristrip is known to work well on ABS and other plastics. Non-VOC formula. You'll find about as many DIY strippers as there are recommendations. Pure isoproanol or methanol, Easy-Off Oven cleaner, brake cleaner... Testor's (they of the scale model kits) has a stripper of their own that claims to be safe for plastics.

You pays your money and takes your pick...
 
With everyone also suggesting brake cleaner, DO NOT substitute with carburetor cleaner.
I have melted screwdriver handles to explain why you should not bring that around most plastics.
 
Yes, but then, brake cleaner doesn't make you all woozy :). No really, carb cleaner is nasty stuff; even the so-called "green" stuff is pretty destructive.
 
bladamson said:
I have a spare IIgs case. It has some damage, but fixing the damage with some bondo and wire and touch-up painting it might be easier than stripping the paint off what you have. Or you may at least be able to use the top cover (it has some damage too, but would be the easiest to fix).

It was a victim of poor packing from an ebay seller. Let me know if you are interested and I'll snap some photos sometime tonight when I get tired of playing Wasteland 3. :3

That is interesting that you had to recap it. I've seen a billion Macs with bad capacitors, I've never had to touch any of my Apple IIs (including 4 IIgs boards). The mainboards I mean. I have had a little trouble with one power supply, but only one.
Click to expand...

Thanks Lee, I appreciate it but this case plastic is fine, no cracks. Only issue is one tab in back is broken off which is common. I think I need to do it out of spite. cleaning a case is easy. Retrobrighting is easy. I know some think it is not good in the long term, but painting a case blotchy shades of yellow seems even worse. I'm going to fix it just because I cant stand shoddy work.

As for the IIgs caps the psu's need the 1uf 50v caps replaced and the board needs the 1000uf 16v and 1uf 50v replaced. These seem to be the usual ones to go bad so I just replace them. In this case the 1000uf caps were bulging. The psu 1uf caps were just shot. Board worked fine beforehand but its not much work. And yeah.. all the macs have bad caps... terrible design.



TO ALL: And thanks everyone, I am going to try oven cleaner, ammonia, and brake fluid. (I know you guys mentioned brake cleaner too which doesnt make much sense.. which is it brake fluid or cleaner? I can rub the plastics with semi metallic brake pads if you think that may work :grin:
 
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Be careful with brake fluids. Be careful with oven cleaner. Whatever you try, drape a paper towel over am inconspicuous area and wet the towel. Watch what happens. You never know how some chemicals will react with that particular plastic composition.
 
Are you sure it was really painted by someone? Can you post a picture?

I don't own a IIgs, but a couple of Apple systems used a colored coating instead of dyed plastics, which may look very similar to paint. Trying to remove that will damage the case. The blotchiness when trying to retrobright the IIgs is also quite common, so your case was probably just how it left the factory.

Even the Modern Vintage Gamer ruined his IIgs:
https://www.youtube.com/watch?v=eBrJw3Ui-gQ
(from 6:55 to 7:50 for the relevant stuff)
 
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yeah Its paint. I have worked on a few dozen IIgs computers before I am very aware of how the plastics should be. Plus I verified it with a cotton swab and acetone which removed paint from a small area.

From what I gather the rf shield was rusty and stained the plastic, so the guy spray painted the whole thing.
 
Since noone mentioned if it was brake fluid or brake cleaner I used neither. I did buy a large can of oven cleaner. And I can say that is a BUST! It loosened some of the paint when I let it soak for 3.5 hours but not all of it. For the price of a can of oven cleaner Id say not worth it. Plus I only got to partially treat the base and front small cover. I didn't get to do any of the top. I will try ammonia but believe it or not the whole cleaning section was sparse when I went and they didn't have any. This is really turning into a S*#t show.
 
Look, you can use starting fluid as a headache remedy, but nobody in their right mind recommends it.

Get a small container of 3M Safest Stripper and give it a try. No gloves, no fumes, water-based. If it doesn't strip off the paint, at least it won't hurt anything.

Or go find a can of the Testors stripper, which is specifically made for the purpose.

That being said, I need to refinish my entryway (wood) door, which has heaven-only-knows how many coats of peeling spar varnish on it. I'm going to use the methylene chloride-based aircraft stripper on it (gloves and outdoors) when the daytime temps dip below 80F. I wouldn't dream of using the stuff on plastic.
 
Thanks Chuck. I can give that a try.

BTW, isnt starting fluid just Ether? Which historically was used to anesthetize anyway?
 
But it works a charm! And most cans say "do not use to start engines, Do not spray into carburetor".... So they intended people to huff it perhaps??
 
It's what I call a "wink-wink, nudge-nudge" product. Like DMSO (dimethyl sulfoxide). All bottles and jugs of the stuff that I've ever seen are labeled "For solvent use only". Uh-huh, that's why people with arthritis and sports injuries buy lots of it.

Come to think of it, have you tried it on your box?
 
. . . Uh-huh, that's why people with arthritis and sports injuries buy lots of it.

Maybe like Absorbine as opposed to Absorbine Jr.
 
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