Right Acrylic for a diffuser

[saltyfilmfolks]

How do you know when you have sanded enough? Assuming some sort of uniformity

Yup. Exactly.

Take a scrap piece and lightly sand. Then keep going. See what happens.
(If you kept using finer and finer grits you’d actually wind up polishing it to clear again)

 

[oreo54]

So, simply put. Anything clear is a good diffuser and impacts light insignificantly for our needs.

Use a lux or fc meter to make sure it’s not cutting too much.

Err not quite ..depends on if you are running a lot of 400 or less nm diodes.
And LUX or FC meters are useless (practically) for that bandwidth..

BUT since, in general that range is a SMALL proportion to overall photons.. err OK..

 

[saltyfilmfolks]

Err not quite ..depends on if you are running a lot of 400 or less nm diodes.
And LUX or FC meters are useless (practically) for that bandwidth..

BUT since, in general that range is a SMALL proportion to overall photons.. err OK..

Err. I think we’ll agree to disagree.
56kt12 and 48k leds grow coral just fine. Great in fact.

So cheap plexi and sand paper or rosco 216 ain’t gonna do nothing to a Radion.
Unless you set the overall intensity too low. even if you set it with a lux meter.

 

[theatrus]

To summarize:

Shortest wavelength 420nm or 445nm? Use whatever

Shorter than that? Make sure to use a PMMA without UV additives, or glass, since otherwise you’ll just filter out the lights you’re paying to run and it won’t reach the tank.

 

[theatrus]

Err. I think we’ll agree to disagree.
56kt12 and 48k leds grow coral just fine. Great in fact.

So cheap plexi and sand paper or rosco 216 ain’t gonna do nothing to a Radion.
Unless you set the overall intensity too low. even if you set it with a lux meter.

No, it won’t do any harm to the ratio and wavelengths, as cheap plexi doesn’t filter violets or UV appreciably (as long as it’s acrylic, and not another plastic).

Will it drop light output? Yeah. But it will do so evenly over the band and loss could be approximated with a LUX meter that’s cosine corrected.

 

[saltyfilmfolks]

No, it won’t do any harm to the ratio and wavelengths, as cheap plexi doesn’t filter violets or UV appreciably (as long as it’s acrylic, and not another plastic).

Will it drop light output? Yeah. But it will do so evenly over the band and loss could be approximated with a LUX meter that’s cosine corrected.

Yup.
Lux meter. $15.

 

[oreo54]

To summarize:

Shortest wavelength 420nm or 445nm? Use whatever

Shorter than that? Make sure to use a PMMA without UV additives, or glass, since otherwise you’ll just filter out the lights you’re paying to run and it won’t reach the tank.

Guess since we are throwing out Radions and the like..
Rough composite showing nothing in the "cutoff" range..

you start losing it even w/ PMMa at 400,390

• LED UV (390nm) [120°] x2
• LED UV (400nm) [120°] x2

 

[adw]

Good to know thank you.

 

[oreo54]

Note the purple "cone" chart also cuts off at 380..so it's missing some of the left hand
spectrum.
Also it"s "theoretical"..
Would like to see "real life" numbers but at least food for thought...

You could "pour your own" clear silicone (floppy) covers I suppose.
https://www.ledsmagazine.com/articles/2006/03/silicone-materials-development-for-led-packaging.html
going way outside the box here..;)

High optical transmittance in the UV-visible region
• Can be synthesized to cover a wide range of refractive indices from 1.38-1.58
• Excellent photo-thermal stability
• A variety of cure chemistries for easy processing
• High purity
• A wide range of cured moduli from gels to hard resins.

Most UV LED diodes are lensed w/ either glass or silicone I believe..

for fun..
https://consumer.dow.com/content/da...k-prod-info/45/45-1612-01-lsr-3d-printing.pdf

Defining Shore A of 50
https://www.smooth-on.com/page/durometer-shore-hardness-scale/

Huh.. found this (no idea of the cost or really material..)

20-3401
MEDICAL, OPTICAL AND SEMICONDUCTOR GRADE
EPOXY RESIN
https://www.epoxies.com/products/potting-encapsulating-and-casting/
Spectral Transmission
@300 nm ≥94%
@400-1,200 nm ≥99%
@1,200-1,600 nm ≥98%
82 hardness Shore D

20-3401 is a low viscosity system with an extended working time. It is designed for L.E.D. encapsulating, an underfill for flip chips, glob top encapsulation, fiber optics, and any potting or adhesive application requiring clarity. It has excellent adhesion to glass, quartz, most plastics, and metals.

Hardness of PVC pipe..
sorry going down rabbit holes is a sickness.. ;)

 

[adw]

You try it first and ill copy you. :)

 

[oreo54]

You try it first and ill copy you. :)

I requested a sample.. and pricing.
I'll see how it goes. Different type of project but same need though..

 

[theatrus]

I requested a sample.. and pricing.
I'll see how it goes. Different type of project but same need though..

Interesting line of thought. I have some clear casting epoxy, wonder what happens if you fill it with glass beads.

Though to be honest I’d rather just thermally form the Satin Ice material for other shapes than working with a lot of casting.

 

[oreo54]

20-3401
MEDICAL, OPTICAL AND SEMICONDUCTOR GRADE
EPOXY RESIN

Sample is being shipped today.. I'm all a twitter.. ;)

 

[adw]

Can't wait to here how this works out

 

[Thatguy96]

Starting to think I should have just bought the radion diffusers lol

lol - I wish they would just include the diffusers with the light. Not sure why something like this that is so beneficial for a hobbyist success would also go up in price :(