Guys I keep my Lego collection in a room that sunlight doesnt hit. The room has the windows open so daylight comes in, but it is not direct sunlight.
Am I safe from discoloring issues or should I just cover them up with a fabric or something?
Effect of UV Radiation on Plastics:
UV energy absorbed by plastics can excite photons, which then create free radicals. While some plastics cannot absorb UV radiation, catalystic residues and other impurities will often act as receptors that lead to degradation. Small amounts of these impurities are sufficient for the degradation to occur, which in the case of Polycarbonate will initiate color instability. In the presence of oxygen the free radicals form oxygen hydroperoxides will lead to a brittle structure. This process is often called photo-oxidation. As an example, a polyvinyl chloride (PVC), window frame exposed to sunlight undergoes discoloration, loss of impact strength, chalking, and a reduction in tensile properties in addition to other chemical changes.
Common synthetic polymers, in addition to PVC, which may be affected by UV include:
Polypropylene
Polyolefin
Poly methyl methacrylate (PMMA)
Polyethylene
Aramid Fibers such as Kevlar®
POM (Acetal)
Polycarbonate
ABS
Polystyrene
PA6/6
UV-A rays cause more serious long-term damage. They penetrate and ruin your carpets, fabrics, window treatments, wall coverings, and fine wood furnishings.
UV-B rays quickly bleach and burn surface colors.
Regular clear glass windows block only about 25% of UVA and most of the UVB radiation.
Curtains can be more or less protective, depending on thickness, color, fabric type and many other factors.
Tinted and reflective glass will block a lot of visible light, reduce UVA by 50 to 75% while still blocking most of the UVB.
Low-E (low-emissivity) glass acts similar to regular clear glass unless specifically treated with UV reducing properties.
There are some specialty glass available specifically designed to block UV light, but are generally only used in commercial structures (laminated glass panes and specially coated UV-blocking panes), blocking 80 to 99% of UVA and all UVB.
You can
reduce fading by applying a clear window film that filtres UVA and UVB. I'd recommend going with a product from an established manufacturer such as 3M (
http://solutions.3m.com/wps/portal/3M/en_US/Window_Film/Solutions/ )
I only did a quick search for whats available easily online (i.e. Amazon) and here's one I found that
may be OK to use (I haven't researched the company at all and can't say anything about the quality of this product). You can get a 36-inch x 15-foot roll for about US$30. The company claims that 99% of all UV light can be blocked with their product.
http://www.amazon.com/Gila-LES361-Control-Residential-Platinum/dp/B000KKM8EG/ref=sr_1_1?s=hi&ie=UTF8&qid=1453226374&sr=1-1&keywords=uv+film+3m
My guess is you are safe. Nobody ever says to wear sunscreen inside during the day. I only worry about direct sunlight and extreme heat.
Hate to tell you that you are not safe, you only mitigated the effects. UV rays can bounce off many objects and enter you home indirectly. Though they may not be as strong as being outside on hot sunny day, they will still cause long term damage.
So, if you plan on having your sets on display for many years, you're still at risk.
On a side note, one of my best friend's father was instrumental in developing the UV Index we all see on local weather reports around the world while working for Environment Canada in the 80's and 90's.
The Lego Balrog by siegfried_fm, on Flickr
The Lego Balrog by siegfried_fm, on Flickr
