So, UV photos...well problem is a weak LED light and therefore long exposures...

I needed a strong source of UV light....specially for underwater use...
All my led's power is calculated at 3,6V x 2A .... 7,2 Wat's..ad dissipation.. collateral looses...and so on. Weak.
Long lightning is good... but I need short exposure, to avoid movements.
I need strobe/flash .... about 160Wat/s...short strong UV light...and here it is....

Step 1: Woods Glass

This glass is a UV band pass filter.
You can usually find this on a bulbs for Disco/Party purpose. All teeth under this light are white :)
Cheapest way to get this glass is a bulb. So, get the bulb, remove metal and wires....
Break a small tube and let air inside...

Step 2: Cutting

Do not try to correct this on normal grinding wheel.
Woods glass is fragile and you shall get smaller and smaller pc's.... :(

Step 3: New Attempt

I use thin diamond grinding plate/wheel. Practiced first on smaller diameter and finally on half, to get biggest diameter sphere. I correct sharp edges on fine water grinding stone by hand,,, long gentle grinding...

Step 4: Top Part

I put sphere in a plexi and glue this with epoxy glue...to make a black cover on my old underwater Marine Sunpack 32 flash.

Step 5: Assembling

Then I add a snap on cover on my normal UW flash, powered from camera, which was connected by 4 optical fibers with snap on ring on Sunpack body to guide light impulse on slave sensor on Sunpack flash...