Aging Plexi?

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jim_p

jim_p

SGF, Supreme Grumble Framer
Joined
Apr 8, 2007
Posts
2,151
Loc
Natick, MA
On more than one occasion when I've proposed plexi to a customer for a large job they hesitated... and their biggest worry was that the plexi would yellow over time. Is this a realistic concern? Yes, I've seen frames from the 70s with thin, brittle, yellowed plastic, but does this happen with the materials we use today?

Along the lines of the "return policy" thread, my assistant suggested that we offer a "replacement guarantee" if the acrylic does yellow. Does this seem reasonable? How long of a guarantee would you suggest? (5 yrs? 10?)
 
In the 23 + years of framing, I have not had any of the acrylic/plexi yellow. Scratched yes, cracked yes, yellow no, under normal indoor situations.
 
You are thinking of polystyrene. .. I believe.

Acrylic might yellow a bit if left in direct sun for a very long long time, but polystyrene becomes yellow and brittle.

Cheap yukky stuff.
 
Yep the styrene is the stuff that yellows. Quality acrylic will not yellow with time.
 
From a plastic company:

Q. Does acrylic (Plexiglas, Lucite) yellow in the sun?

Since the beginning of the creation of plastics, many myths have been perpetuated about the longevity of plastics, especially outside in the elements. All plastics come from petroleum and natural gas. Sunlight, especially ultraviolet radiation, has a disastrous effect on most plastics. Some plastics, like polyethylene (PE) milk jugs, degrade quickly in the sun - in a matter of months. PE can easily be recycled. Many children's toys are made from PE and get brittle and crack when left outside.

Acrylic (Plexiglas, Lucite,and Acrylite) comes from natural gas and is completely inert when in solid form. American-made acrylic does NOT yellow in the sunlight. Witness the protective canopies and bubbles in the World War II bombers - they are still clear after 50 years in the sun! There are three other clear plastics that do yellow in the sun and get confused with acrylic - Styrene, PETG, and Polycarbonate. They have their respective qualities that make this an acceptable trade-off. ​
 
I just had this same conservation with a customer a few hours ago.

When talking to a customer I call it picture framing acrylic and add that it's far superior to styrene.

Doug
 
DVieau2 said:
When talking to a customer I call it picture framing acrylic and add that it's far superior to styrene.
Click to expand...

Doug, this is really smart. A lot of framers say they are using Plexiglas when indeed they are using a different, perhaps better, brand of acrylic. Plexiglas is simply a brand name but the word is used generically to describe acrylic.
 
Acrylic is so chemically stable that paper conservators use it all the time in framing. Be wary, however of Chinese-made things labeled 'acrylic', and doubly wary of Chinese-made UV-filtering acrylic. I'm not sure what all the issues are, but my supplier (who is far from a jingoist) warned me off.
 
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