Lexan drops - Which side is UV?

[mattready]

So we have a ton of drop left over from panels we have cut. Problem is they were not properly marked when they were cut and now they have nothing to distinguish the UV side. Anyone have a tip/trick to figure this out? Thanks in advance!

matt@signshopltd.com

 

[ChicagoGraphics]

sure

welcome to signs 101

 

[BIG EASY DOES IT]

Polaroids show up only when light is transfered onto them correct. Black cloth stops light but not UV light. Put an unexposed poloroid under the plexi with a black shirt over top and let it sit outside for a day. If it changes then you know you have it the wrong way. And vice versa.

That's the only thing I could think of otherwise. Welcome To :signs101:

 

[mattready]

thats a cool idea. do they even have polaroids anymore i was hoping there was a marker or pen or chemical to test with.....hmmmm maybe i should come up with that?

 

[BIG EASY DOES IT]

Your other option could also be some sort of test with screen printing emulsion which is also UV sensitive.

 

[J Hill Designs]

my only problem with the above steps, is the UV will still get filtered from the 2nd surface down...they only reason for the UV protection is so the face doesnt yellow...I doubt the UV protection is 1-way only