Transilluminators

(Under construction - photos and build hints to be added....)

A “trannie” typically has 15W MW bulbs installed (312nm). Some have 6 bulbs, some have 4. So far, almost every unit I have come across has Hoya U325c glass (SW glass). Since they have been run using MW bulbs the filters are not solarized and perfectly suited for our application. Various units have various filter sizes – 8” x 16”, 8” x 8”. The larger filter the better of course. CAUTION: there are some trannies which are LW and only have LW filter glass.

For the most part I have found these units to be scuffed, rusted, abused, etc – but the glass is usually pristine and the ballasts work. Sometimes the glass can be scratched from scientists cutting their gels directly on the glass, but aside from cosmetics these seem to work just fine.

It’s a simple job to replace the MW bulbs with SW bulbs (ozone free) and you have a 60w/90w SW display lamp with a 8” x 16” filter – huge and bright.  With electronic knowhow you can replace the ballasts and install new connectors, new ballasts, and 4ea 60w “U” tubes for a 240w monster light. Or, you can simply replace the magnetic ballasts with electronic ballasts and drive 25W bulbs for a 150w lamp. Some seem to have various types of reflectors – I usually replace them with specular aluminum if they are not already – not sure if that matters a whole lot as the company who designed the unit probably selected their reflector material for optimum UV output – I just don’t like the white reflectors.

I’m always on the lookout for deals: an example of one I just bought today is on Ebay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280268262372 - $120 including shipping. I use these at shows, and for my personal display. Sometimes I buy them just for the glass – vastly cheaper than buying new glass. This was (I think) an exceptional deal – usually they sell for around $200 plus shipping.

Manufacturers (units I have bought) include:

• Fisher Scientific
• Ultra-Lum
• Fisher Biotek
• Fotodyne

Again - be sure that the unit you purchase is a midwave model (typically 312nm). It really doesn’t matter if the bulbs are good as you will replace them. For me, I don’t care about the physical appearance (rust, etc) as I usually paint the entire unit flat black. On some the Hoya glass might be scratched. I have purchased one unit which had SW bulbs in it, and was completely solarized - but that’s one out of perhaps a dozen (and it still works - just not as bright as others).

I will take some photos of the next “build” I do and post them here when time permits.....