Anyone know what LED's are cast from?

[Eric Allen]

I cut the end off of one of the Wal Mart clear LED's from a string, and P U! El stinko grande! The cut end went from clear to a clear tan/brown, and the Mrs. came out to exclaim about the stench. Mind you, I cut acrylic and she never says anything, so for such a little sucker, that was potent! Starting to wonder if maybe it's clear PVC, hard to tell from a burn test.

[Mike Christen]

Good chance its epoxy i think, depends who makes it i guess. PVC test it, use a torch to heat a copper wire, melt a bit on the wire and put it back into the torch flame, if it burns green even a hint of green it has pvc in it.

[Eric Allen]

It was hard to get any on the wire, so I just burned the LED, still kind of hard to tell. It looked a little green to me, but I figured I'd check around and see if anyone else had tried to roast one.

[Mike Christen]

get the wire red hot and try to get a little on it, really doesn't need much. If you can't get it on the wire it may not be PVC not sure though

[Robert Walters]

I believe it's PMMA
http://en.wikipedia.org/wiki/Poly%28methyl_methacrylate

[Jason Roehl]

http://en.wikipedia.org/wiki/LED

That article has a diagram that claims it's epoxy.

[Dan Hintz]

Cool, finally a question I know I'm uniquely qualified to answer

For the type your talking about (cheapy Wal-Mart string), it's guaranteed to be a polymer of some form... for most visible LEDs, it's an epoxy resin (most likely a thermo-set). Some of the blue ones will use a different type, but even the cheapies use it.

[John Coloccia]

It depends on the optical qualities wanted. It can be epoxy or plastic. Both can be rather stinky. I doubt there's any PVC in there but I still wouldn't want to breathe the stuff if I could avoid it.

edit: nevermind. Dan beat me to it.

[Eric Allen]

Thanks all It sounds like I'm probably "safe" to cut them, although, if the Mrs. is home, no guarantee I thought it would be nice to customize the optical properties by changing the lens shape with the laser. Pretty sure the smell is such that it could even attract unwanted attention from the neighbors, pretty unreal.