So… I finally found a use for my DST. I ordered a 5500k XHP70, carefully sliced the dome down and lightly sanded it to give a frosted effect to eliminate the XHP “donut”. I built a FET+1 driver with a zener mod, assembled everything, fired it up with some half-charged Samsung 20R’s and… immediately started giggling. It was so bright! Within about 20 seconds though it started turning green and holes appearing in the hotspot. Oh no! I immediately assumed I had melted the DST’s plastic reflector. I opened it up, and this is what I found.
Somehow my precious reflector (mostly) escaped without damage, but what happened? I’ve ruined emitters before but not in such a spectacular manner. I have a spare XHP70, but how do I avoid this happening again?
It looks like the dome material burned. Did that light frosted effect trap light/heat? Or did just everything go poof from all that wattage? Have you identified all the burned/melted materials. It does look well heat sinked. I’ve actually warped a diffuser from heat that I placed too close on a triple build P60.
The frosted finish is the only thing I can think of, but I swear I’d seen people talking about doing it with no ill effects. It actually still works, still gives off light under all that mess.
At this point, the emitter is already toast. Maybe break out a fresh x-acto knife blade and try shaving off what is left. Then give it a go without the sanding.
Place a piece of white paper in front of an XM-L2 at a few amps. Bring the paper to touch the dome if you don’t care much about the dome. The paper will burn. There are concentrations of energy greater than some powerful lasers at the dome. Always use a filter away from the LED. Creating one near it is going to drop lumens and maximize heat at the die, as seen here.
