DIY: Converting a Transilluminator into a Short Wave Lamp

My small hand-held short wave lamp is useful, but has its limitations. I was interested in a much more powerful light for display and photography. After some research and talking to collectors with large displays, I learned about the transilluminator, a piece of laboratory equipment which is essentially a large enclosed filtered UV lamp. I learned that a mid wave transilluminator can be changed into a short wave lamp by replacing the tubes, and I learned that I could gut the fixture and build an even brighter lamp. Having electronics experience myself, that was the option I chose. I bought a used transilluminator and successfully converted it into a 240 watt lamp.

I could not have performed this conversion without the excellent DIY guide on transilluminator conversion from MinerShop, written by Mark Cole. It contains useful and highly applicable advice on this topic and is required reading for anyone undertaking a similar project. I decided to document how the conversion process worked for my particular fixture from start to finish, and I present it in the photo gallery below.

Electrical work is dangerous. Do not attempt a project of this nature without a strong understanding of light fixtures, wiring, and electrical safety.

The first order of business was choosing a transilluminator with a low price and a big filter. I found a good deal on this Fisher Scientific model with a 14" x 6" filter. The glass is beat up from use and has a crack across its width, but this does not matter for my purposes and does not affect functionality.

Unsurprisingly, it's dirty inside. I used the light a few times before tearing it down. I'm kind of amazed that these UVB tubes worked, because they all fell apart when I removed them. I could simply put in new tubes for a 90w light, but I am going to take out what's here and upgrade to 240w.

Fulham Workhorse 5 ballasts and Philips TUV PL-L 60w bulbs. The best price for them was on Amazon. The 2g11 bases and the metal bulb clips I got elsewhere. I later learned that 2x60w bulbs is technically out of spec for these ballasts and 2x55w is the recommended maximum. The next model up is advised if you copy this configuration.

Checking out placements. This type of bulb does not emit light from the entirety of its glass portion. For maximum output, I want to horizontally align the portions of the bulbs which do light up, with the filter glass on the lid. I was lucky with this model; I won't have to do much to make that happen except mount the bases as far back as they will go on these rails. To do that, I just need to drill several holes. I can even arrange the bulbs in alternating directions, and they will still align properly with the filter.

Beneath the reflector, the old ballasts and wiring. For some reason there's no fuse in here, so I'll have to add one. The power cord is beat up, so I will replace it as well. Basically, this is all coming out. Only the switch and fan will be re-used.

Marking the holes for drilling required no tools because the four bases just barely fit flush inside the reflector. I drilled through the reflector and the bar below it together, then filed each smooth.