P.S. Sorry that some of the images are sideways, I didn't have time to rotate them.
Step 1: Parts And Supplies
I chose 365 nm and 380nm leds because they are really the only available UV LEDs, they are reasonably priced, and give the UV light a wide range of use.
For parts, this is what you need. The total cost of this project was just under $70, but you get all the extra UV leds as well.
Prices are in CAD
x100 380 nm LEDs - 30.49 (free shipping)
x20 365 nm LEDs - 21.12 (without shipping)
3mm clear green LED - 1.50 (bought locally)
LED Worklight - I chose one that was already cheap and turned out to be on sale for 9 bucks, with a 4 LED flashlight and 28 LED work light that sprung out.
As you can see 380nm LEDs are much cheaper than 365nm, and that's good because most uses are in the 380nm range, so I used them to modify a few flashlights, and have spares for whatever I'd like.
The flathead screwdriver is for opening this light as it does not have any screws, yours will probably differ.
So, according to the site I linked to earlier, my finished UV light will be able to be used for all these things:
Anqitue glass (uranium glass, vasceline glass)
Forged document detection
A/C coolant leak detection (using dye)
Arson Investigation Flashlights Lanterns
Hotel room inspection
Mineral Hunting (diamonds, etc.)
Salmonella and Shigella bacteria detection
Contaminate inspection (clean environment)
Drivers licence UV markings
Dye penetrant inspection (NDI/NDT)
Magnetic surface analysis
Counterfeit currency detection
UV Curing (requiring 365nm)
Note that blood requires 465nm wavelengths, so it won't work with this, however if you use luminol, which reacts to the iron in the blood, it might work.