Back in 2000 when we furnished our new home, we were seduced by the FLOS Lastra 8 Rectangular luminary, so we decided to get one for our dining room over the dining table. Both the table and the Lastra are essentially made out of glass, so they fit very well.

Our enthusiasm was dampened about one year later when we saw that the “8 pressed glass diffusers with high-temperature resistant white finish” (quote from manufacturer) started to lose their “diffusers”: a white dye that effectively fell off the glass, due to the high temperature of the 8x35 Watt halogen bulbs. But we did not dispair, the glasses looked OK even without the dye. But the really bad things started about four or five years later, when the whole electrical connexions begun to let us down. Due to the hot halogen bulbs, the connexion screws lost their contacts to the silver tracks on the glass plate and the lights went out one by one. I replaced all the connexions with self-adhesive copper tape and re-glued the screws on the glass with special Loctite glue. However, every now and then I had to re-glue the screws, as the temperature was really too high. It is a typical italian product: outstanding design, poor technology.

So after more than 14 years of use I decided the time has come to “LED-ize” the luminary. But, instead of going the easy way and simply replace the MR11 halogen spots with equivalent LED variants, I decided to use high quality LEDs mounted on a custom heatsink system. This is because the currently available LED MR11 spots do not provide enough light (they should provide at least 350 Lumen) and the light quality of a commercial LED spot is rather poor. So I used Osram Oslon SSL80 LEDs that have a typical CRI of 95 (I used the type LCW CQ7P.CC). Depending on the drive current, one Oslon can deliver over 100 Lumen, so I decided to use four LEDs per lighting element.

The “adventure” of this conversion is described in the following pictures.