Plastic yellowing: Light + heat?
Posted: Wed Jul 10, 2019 8:10 pm
I've just brought my TT back down from the loft and it's very much more yellow than it was when it went up there a few weeks ago. The previously retrobrightened parts have almost returned to their previous colour.
I've seen reports that heat accelerates or "develops" the yellowing of plastic and I think that this proves it as we've had some very high temperatures recently, which would have been even higher in my loft.
The plastic the TT's made of seems particularly light sensitive now, though it wasn't when it was new. It spent its first few years in a brightly light room and didn't yellow at all, it was only during the storage, after 1995, that the colour turned, and that was only in the areas previously exposed to sunlight. Now the plastic is quickly yellowing even in the other areas, suggesting the plastic is now far more photo-sensitive.
It's quite possible that to make the TT look the correct colour I may have to spray paint it with a satin-white paint.
P.S. Some of the areas which have re-yellowed have not had much light exposure since the retro-brightening, suggesting that this is old photo-effects triggering the yellowing. Also, when the machine was in the loft over winter there was no yellowing, suggesting that temperature is a major factor.
P.P.S. The keyboard, which had been retro-brightened again just before going into storage has also gone yellow again.
I've seen reports that heat accelerates or "develops" the yellowing of plastic and I think that this proves it as we've had some very high temperatures recently, which would have been even higher in my loft.
The plastic the TT's made of seems particularly light sensitive now, though it wasn't when it was new. It spent its first few years in a brightly light room and didn't yellow at all, it was only during the storage, after 1995, that the colour turned, and that was only in the areas previously exposed to sunlight. Now the plastic is quickly yellowing even in the other areas, suggesting the plastic is now far more photo-sensitive.
It's quite possible that to make the TT look the correct colour I may have to spray paint it with a satin-white paint.
P.S. Some of the areas which have re-yellowed have not had much light exposure since the retro-brightening, suggesting that this is old photo-effects triggering the yellowing. Also, when the machine was in the loft over winter there was no yellowing, suggesting that temperature is a major factor.
P.P.S. The keyboard, which had been retro-brightened again just before going into storage has also gone yellow again.