Will the Acrylic Shield on a Black Box Filer UV (Sub 400)?

[RevMH]

Hello R2R.

I have 395 and 365 LEDs (3W Epistar "Egg" type) on some of my Black Boxes (Lightmetunnel WiFi). Are these accomplishing anything with the Acrylic Shield in place, or does all the UVA get filtered out?

If they aren't helping, I'll swap them for something more beneficial.

I saw some forums regarding these topics with posts from @oreo5457 (call out to Oreo for helping me in the past!), but I don't know if there was ever a clear answer.

As always, thank you, R2R.

 

[Ron Reefman]

Is the Acrylic Shield a product brand name? Do they say it blocks UV? Or do you just have a piece of ordinary acrylic in place?

 

[RevMH]

Is the Acrylic Shield a product brand name? Do they say it blocks UV? Or do you just have a piece of ordinary acrylic in place?

Thank you for replying back. It doesn't have a brand or anything associated. Probably something cheap, since it's a black box.

Looks like it's a regular piece of acrylic or plexiglass. There to stop the water from entering the electronics.

 

[EMeyer]

Every black box I've ever owned had a glass shield, not plexiglass. Are you sure its not glass? I believe they have quite different absorbance of UV.

 

[Spieg]

Many lights on the market use optical grade polycarbonate shields without problem. If you are unsure of what your shield is made of, you can probably replace it with a thin sheet of polycarbonate cut to the same size.

 

[oreo54]

Thank you for replying back. It doesn't have a brand or anything associated. Probably something cheap, since it's a black box.

Looks like it's a regular piece of acrylic or plexiglass. There to stop the water from entering the electronics.

most plastics start their cutoff before glass..

Infrared and Ultraviolet Transmission in Plexiglass Acrylic and Makrolon Polycarbonate Sheet

Well, this explains everything. I finally got my hands on the charts to show UV, Visible, and IR light transmissions in Plexiglass sheet. An...

www.plasticgenius.com

same w/ polycarbonate..
thickness matters as well

365's, unless by some Chinese miracle, would probably not be very effective...even normal glass wouldn't be great.

 

[RevMH]

Thank you, everyone, for your replies.

@EMeyer
It's definitely a "plastic" material, maybe it a cheaper type then most others (sigh)?

@Spieg
If I can find something that allows transmittance of the UVA (for a reasonable cost), I'll certainly replace what came stock.

@oreo5457
Thank you for sending that. Looks like a probably have a good shot of the 395 getting through, but almost none on the 365. I'll pull those out of the fixture, no reason to have them if they are being filtered and running without shield feels too risky.

 

[oreo54]

Thank you, everyone, for your replies.

@EMeyer
It's definitely a "plastic" material, maybe it a cheaper type then most others (sigh)?

@Spieg
If I can find something that allows transmittance of the UVA (for a reasonable cost), I'll certainly replace what came stock.

@oreo5457
Thank you for sending that. Looks like a probably have a good shot of the 395 getting through, but almost none on the 365. I'll pull those out of the fixture, no reason to have them if they are being filtered and running without shield feels too risky.

Well the "MC" is normal plexiglass and not too bad..You might get 10-15% out..
Obvious problem is what is it exactly and what its real absorption is.
"G" is cell cast.



Glass

Actually the lenses are probably more of an issue than the splash guard I believe.
Little black dip is about at 350nm. PMMA = Acrylic. Seen charts w/ better response at the UV though)
PET is polyethylene.

Removing the lenses (going 120 not 90 degree ) and replacing the splash guard w/ plate glass makes it doable AND without question (well as long as it isn't UV blocking treated glass

Too many unknowns for a really solid answer on the plastics involved.
Theatrus here did a lot of real life measurements of real materials.

 

[RevMH]

Well the "MC" is normal plexiglass and not too bad..You might get 10-15% out..
Obvious problem is what is it exactly and what its real absorption is.
"G" is cell cast.



Glass

Actually the lenses are probably more of an issue than the splash guard I believe.
Little black dip is about at 350nm. PMMA = Acrylic. Seen charts w/ better response at the UV though)
PET is polyethylene.

Removing the lenses (going 120 not 90 degree ) and replacing the splash guard w/ plate glass makes it doable AND without question (well as long as it isn't UV blocking treated glass

Too many unknowns for a really solid answer on the plastics involved.
Theatrus here did a lot of real life measurements of real materials.

Thank you very much.
I removed the lenses, already, but I'll look into replacing with plate glass. I appreciate the help and all the diagrams. Your helping of other people gave me a lot to research before posting a question!