The hardest part was figuring out the lights, since there are limited resources here in the "country". (I live about an hour out of Savannah, GA) If you are only going to do smaller plates and have the resources to buy one, get a facial tanning lightunit from ebay or from a supplier. Solarplates need UV light to expose, so the tanning units work great. Then all you do is just build a box around that. Note, regular fluorescent lightbulbs won't work.
I wanted to make a little bit of a bigger unit, to accomodate larger plates, so I built one out of MDF to house two- two lightbulb- ballasts. (total of 4 bulbs) The cost ended up being about $100 for everything.
4- 2' blacklights that you can get from your home improvement store or even at Walmart
2- 2 bulb ballasts (Lowes)
Some screws and wood glue
Above. Here is a picture of the finished box with dimensions. I did not wire the cords from the two units together so you have to plug them in separately for now. Addition: You can plug the cords into a surge protector, which makes using them easy, since it has a switch on it.
Below. A picture from the inside of the box
A picture of the sides, the little strips are to make carrying easier. If yo plan on using the unit a lot, you might want to drill a couple of holes on the sides to let some of the heat out.
With this unit, the lights are about 8" away from the plate, and we have tested exposure to be 1 min 30 sec. For aquatint screens we have been doing about 1 min 10 sec first with the screen, then the same amount of time with the image.
Hope this is helpful to you. If you have any questions, please ask.