[island911]

Originally Posted by cashman

btw2; Paradoxically, Windex says that their (ammonia) product is fine for PC.

The ad does not mention PC? It mentions Lucite =Acrylic, Plexiglas, and Plastic = ?. It does not specifically mention PC...

Right, but PC IS a plastic, and LCD's are often PC. --some coated, some not.

Originally Posted by cashman

...Either way, PC is an amorphous plastic highly susceptible to chemical and oil attack. Ammonia is one of the chemicals. Also, the PC you purchase for window glazing is not "stress free", it is produced by squeezing hot melted PC between
(2) polished calandar rollers and it hardens quickly on-line. Stress free PC has to go through and annealing process and it does not for this product. You can purchase machine grade PC which has been annealed but that is usually 5/8" and thicker and you should only use water as a machining coolant. ...

Being an amorphous material does not make it highly susceptible to chemical and oil attack. --Again, just look at the clear plastic bottles which cleaners come in; which are made of non-crystalline amorphous plastic.-- It's the chemistry that maters,

Also, Being an amorphous (and non-crystalline) material, does however mean that it will "self-anneal" over time. Yes I realize PC can hold some internal stresses, but those are very small. Certainly not the type to increase chemical sensitivity.

What I'm really trying to get at is the degree of (in)compatibility; which you seem to allude to here:

Originally Posted by cashman

...The flat surface of the PC forms a skin while extruding and will offer some protection for the quick spray but you really have to be careful about the cleaner getting to the exposed cut edge. ...

The thing is, until yesterday, I had never heard of a warning about using something like windex on PC. ...and I should note that my understanding of engineering plastics is important for me. Not only do I design many consumer and medical product with PC (lots of lenses and light pipes) but I've also taught an engineering plastics course for a few years.

Anyway, this warning, I suspect, is nothing more than an over-hyping of a slight incompatibility. ...but I would love for someone to demonstrate otherwise.

Aside, I have read that Rain-X works well to help protect PC. --seems reasonable.