The Definite "Cleaning Yellowed Plastic" thread

[chiark]

Not sure I understand your post's message. We're trying to find a way to unyellow the plastic without just removing the yellow plastic... But of course, sanding it off will work . Will the varnish completely stop the degradation and, if so, what sort of varnish?

[Merlin]

@ laser & chiark

No varnish will truly stop degradation, the fact that coatings are designed to be slightly unstable so that the driers and coalescent agents can do their work (don't ask, I'll be here all night explaining this) and they all degrade and oxidise with age. You can add anti oxidants and UV absorbers but all they do is slow it down, they don't stop the degradation.

The Amiga plastic is probably an acetal styrene butadiene / terephthalate type so you definitely are onto a loser, unless you just use it in the dark.

Just paint it and be done with it.

Merlin

[chiark]

Ah, the old terephthalate type eh? I suspected as much

[Merlin]

@ chiark

The sad thing is, I actually understand this stuff....

PET (Polyethylene Terephthalate) is what pop bottles are made from, it's not a Welsh railway station.....

PMSL

Merlin

[klx300r]

Originally Posted by Merlin

If cleaning doesn't help.....

The answer is Austin Rover acrylic car paint in Old English White, .....

I prefer commie blue

[laser]

Originally Posted by chiark

Not sure I understand your post's message. We're trying to find a way to unyellow the plastic without just removing the yellow plastic... But of course, sanding it off will work . Will the varnish completely stop the degradation and, if so, what sort of varnish?

there is no way to unyellow the plastic with any kind of product if the plastic was exposed to the sun....unless of course if you remove the yellowed layer

any kind of fine varnish will work and will protect the plastic from the air and corrosive agents like cigar's smoke,humidity and others corrosive agents.....

I used transparent varnish for wood...but any other will work..also a fine lacquer should work...but the lacquer generally is based on thinner and the thinner render the plastic...so I do not recommend it

OK

if you disassemble a yellowed A500' mouse for example you will found that the reverse side of that mouse is still white like new...that's cause was not exposed to the air and the others corrosive agents

bye

[laser]

Originally Posted by Merlin

@ laser & chiark

No varnish will truly stop degradation, the fact that coatings are designed to be slightly unstable so that the driers and coalescent agents can do their work (don't ask, I'll be here all night explaining this) and they all degrade and oxidise with age. You can add anti oxidants and UV absorbers but all they do is slow it down, they don't stop the degradation.

The Amiga plastic is probably an acetal styrene butadiene / terephthalate type so you definitely are onto a loser, unless you just use it in the dark.

Just paint it and be done with it.

Merlin

I think that the artificial light is inoffensive to the white plastic....anyways Im not 100 % sure of that....but I can guarantee that the varnish protect the plastic for several years....of course not forever

no one lives forever

[Fingerlickin_B]

I received a keyboard today with filthy, grimy keys.

I want to pop them off and stick them in the dishwasher, but just wondering...what do you do to stop them being tossed around by the water streams?

Obviously I don't want them falling to the bottom of the dishwasher, as that's where the hot element lives!

PZ.

[musashi5150]

Maybe try a mesh bag... like oranges come in or something like that?

[StevenJGore]

Wash them individually by hand! That's how I cleaned my A500 keyboard recently.

Also, I put the two halves of the same A500 in the dishwasher after giving them an initial scrub by hand, and they've come out very clean indeed.

The A500 now looks almost as good as new!

Steve.

[Fingerlickin_B]

Originally Posted by musashi5150

Maybe try a mesh bag... like oranges come in or something like that?

Time for me to go buy some oranges!

[Adropac2]

It probably wouldn't be all that hard to have the cases made in all honesty, certainly wouldn't suprise me if this happens at some point

[Magno Boots]

The dishwasher technique doesn't work for discolouration I'm afraid.

I placed a badly yellowed (on one side) tank mouse case in the washer and left it there for a whole four washes at intensive / 75deg.

The cases were clean and the glides & stickers were hanging off.. but no change to the colour.

[Cerberus73]

only cure ive found.... paint! just repaint them, ive tried everything, bleach, peroxide, oxygen bleach, once the stuff is yellowed there is nothing much that can be done.

if only some smart cookie at a plastics company would realise theres a huge potential market for new cases for vintage/retro machines. why should good hardware be chucked into the back of a cupboard just because its unsightly. if there was a easy way to get new casings and keytops for say amiga's C64's Vic 20's, spectrums, and all the other great old comps still soldiering on out there, then it could do the power of good to reduce inflated ebay prices for good clean machines, that simply for asthetics command far higher prices than aged looking but functional bretheren.

Personally i have a few machines that i keep hidden away because they look yucky but work perfectly. i would love to be able to make use of them or do them up and sell them on to a fellow amiga/c64 user