Article on plastic yellowing

[Blacklord]

Kinda interesting - http://www.vintagecomputing.com/index.php/archives/189

[nikoniko]

Interesting article! I only wish it had an answer for a similar problem I dealt with when I lived in Texas. I didn't take any appliances with me when I moved there, so I purchased new when I arrived. It was perplexing to me that any light-colored items with plastic cases began developing brown or yellow spots within weeks of purchase, progressively getting worse. It happened regardless of manufacturer or which store I'd purchased them from, I don't smoke, and except for a coffee pot, none of the appliances were exposed to heat. I didn't have flourescent lighting, and my apartment was completely shaded by trees, so I didn't get any direct sunlight either. The degradation was so rapid that I found it remarkable, and on asking some other people found that they no longer purchase light-colored items because they'd had the same experiences. Before then the only yellowing plastic effect I was familiar with was the kind discussed in the article you linked.

My only working theory is that it had something to do with pollution. There's a lot of dirty industry in Texas -- oil refineries and the like -- and the air was affected enough that my asthma was reawakened many times worse than I'd ever had it before. I suppose the same chemicals doing a number on my lungs also interacted poorly with certain plastics. Thank goodness I decided to leave after six months.

[xlar54]

Good find. Interesting that its not "smoke damage".  Ive seen this effect with some bathroom tubs actually.  Where light from a window beams down on the tub, the sunlit half starts to discolor.

[adric22]

I live in Texas, just barely south of Fort Worth.  I've never experienced any yellowing plastic except that which was exposed to sunlight or cigarette smoke.  As I don't smoke, my Commodore equipment is just as white as it was when I bought it 20 years ago.  Now I have some other commodore stuff that I bought second hand which is yellowed.  I even have some old Commodore 64 breadbox units that appear brown, even though my original 64 still appears charcoal gray.  Some people dispute the color of the original C64.. I suppose it is possible that it is slightly brown when manufactured, but nowhere near as brown as those exposed to sunlight.

Granted, we do have a lot of pollution from Dallas and the DF/W airport.  And it does upset my athsma sometimes too.  But as far as my Commodore stuff, haven't noticed.

[Guest]

I live in Texas, just barely south of Fort Worth.  I've never experienced any yellowing plastic except that which was exposed to sunlight or cigarette smoke.  As I don't smoke, my Commodore equipment is just as white as it was when I bought it 20 years ago.  Now I have some other commodore stuff that I bought second hand which is yellowed.  I even have some old Commodore 64 breadbox units that appear brown, even though my original 64 still appears charcoal gray.  Some people dispute the color of the original C64.. I suppose it is possible that it is slightly brown when manufactured, but nowhere near as brown as those exposed to sunlight.

Granted, we do have a lot of pollution from Dallas and the DF/W airport.  And it does upset my athsma sometimes too.  But as far as my Commodore stuff, haven't noticed.

I think you are the exception and as such a conscientious owner probably didn't submit your equipment to the type of environment (including heat) that leads to the yellowing effect.  Heat really does appear to be the major cause of the yellowing as equipment gets hot both inside and out, and since heat rises  (and the venting in the bottom of the cases pushes heat away from the bottom half of the computer), it makes sense that these thing would yellow inside and out on the top half of the case.  It also makes sense that the whole case would turn yellow somewhat uniformly because the heat shields in the systems are metal and thus would spread the heat out uniformly within the interior of the computer computer.

[adric22]

Well, I hope you are wrong about the heat.  I just moved most of my commodore collection to the attic a few weeks ago.  It was just taking up too much space in my closet.  Even my 128D is up there, of course it is only partially plastic.  The only ones I kept in the house were my 64c, 1571 drive, and 1581 drive.  Those are the ones I use the most, when I use one at all.  Here in texas, my attic can easily reach 140, maybe 150 degrees on a really hot day in the middle of the summer.   These computers are all inside plastic storage crates.  I don't have to worry about them getting wet or exposed to humidity or anything, but heat will definatly be present.

[nikoniko]

Poor 128D.

If you ever decide you're willing to part with it, please let me know.

[Mark Smith]

Well don't come to New Zealand if you value your plastic toys, the lack of ozone layer has discoloured my TV in 6 months and unless your plastic garden furniture is UV resistant it WILL crumble in about 2 years!

[Blacklord]

Well don't come to New Zealand if you value your plastic toys, the lack of ozone layer has discoloured my TV in 6 months and unless your plastic garden furniture is UV resistant it WILL crumble in about 2 years!

That is somewhat similar to here in the Blue Mountains. 18 months back I got six UV resistant outdoor chairs that are still fine, but the table wasn't - the green surface on the top is slowly decaying to a white powder.

Lance

[nikoniko]

*Note to self: Sell Google stock and invest money in UV-resistant plastics made for outdoor products distributed in Oz and NZ*
*I'll make a fortune... as long as the ozone layer stays crap!*
*Additional note: Must start supporting lax environmental policies*
*shudder*
*Nope, just can't bring myself to do it.*

[Mark Smith]

*Note to self: Sell Google stock and invest money in UV-resistant plastics made for outdoor products distributed in Oz and NZ*
*I'll make a fortune... as long as the ozone layer stays crap!*
*Additional note: Must start supporting lax environmental policies*
*shudder*
*Nope, just can't bring myself to do it.*

hehehehe ... I never thought of it that way :-)

[nikoniko]

This is the worst case of yellowing I've ever seen on a 128. Note the location of the seller.

[Blacklord]

This is the worst case of yellowing I've ever seen on a 128. Note the location of the seller.

And he wants $US120!!!!!!!

Lance