|Re: HP case yellowing. Shout it out.|
Message #7 Posted by Juan J on 21 Aug 2002, 12:28 p.m.,
in response to message #6 by Michael Meyer
Many plastic housings get yellow beacuse of dirt, smoke or direct sunlight exposure. Almost all plastics include additives for UV light protection, color and molding viscosity reduction, among other things.
Sunlight usually degrades the polymer's molecular bonds, and sometimes even the best UV absorbers cannot prevent degradation due to long-time exposure. However, it is easier to deal with dirt or smoke.
HP handhelds housings are made of acrylonitrile-butadiene-styrene (ABS,) a high strength copolymer with good resistence to chemicals. Since it is intended for heavy duty applications, ABS is carefully additivated to reinforce its mechanical properties in the long run, including direct sunlight exposure, heat, abrasion and impact resistance.
Therefore, a soak in oxyclean and soap will not harm any plastic housing. It will remove surface dirt and nothing else. And, as an extra feature, many cleaning solutions have substances known as optic blankers, which adhere to the surface being cleaned and do not absorb visible but UV light, making the surface look even cleaner.
HP might have made somewhat fragile circuit boards or wheels that become gummy in time, but the plastic it used for the housing was the best for the job. Shout the dirt out and make it look nice and clean.
Hope this helps.