Attention
Only attempt to de-dome an LED if you are willing to do an emitter swap or scrap the light! Expect failure on your first de-dome procedure and treat it as a practice run. To maximize chances of success stick to the methods and the appropriate tools suggested
I tried to make a very brief summary of the main methods of de-doming that have been contributed to this thread. Sorry for not linking to the contributors as yet, this is a preliminary summary that I will flesh out later this week when I have time.
The three main methods of de-doming are as follows:
Heating the LED:
The LED PCB can be heated by an iron, stove, or the LED driven at a high current, to the point where the dome softens and can be pried off. Sealing the bare LED afterwards is recommended. Risks involve damaging the LED with heat, dislodging the LED from the PCB when the solder melts, damaging the LED bond wires as well as removing phosphor from the emitter surface. This is the “original” method of de-doming and the most popular.
Heating the LED dome:
An iron or other hot implement is used to heat the dome uniformly until it is soft enough to be pushed off, in the direction of the LED bondwires. Sealing the bare LED afterwards is recommended. Risks involve damaging the LED bond wires as well as removing phosphor from the emitter surface. This method has not received much testing as yet.
Slicing off the LED dome:
A very thin, very sharp blade, such as a razor, is used to slice off the LED dome a millimeter or less above the phosphor layer. A spacer/shim for example a washer of appropriate thickness can be placed around the LED to act as a guide for the blade. The motion of cutting should be a single push or slice to allow for a smooth clean cut. A dremel or fine grit sandpaper can be used to polish of the surface afterwards IF needed. Risks involve nicking the LED with the blade, getting too close to the LED and destroying it during polishing. This method provides seemingly less reliable results than removal of the entire dome provides.
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I’ve stumbled across an easier way to de-dome an XM-L that should yield close to 100% success if one is careful (maybe its been discussed before but I didn’t see it). I just dont know how much light is lost in the process since I didn’t have the good sense to take before and after beamshots.
Anyway The method is to take a razor, like this (the sharpest, thinnest thing I could think of) and just slice the dome off as close to the surface and possible, leaving maybe 1mm or less of material. Mine actually came out quite untidy but the beam still had no artifacts, though this probably affects brightness a bit.
I did it to a UF 3mode dropin. The beam is about 50% smaller and more intense, with a slightly warmer hotspot. Another pro of this method is that the thin layer remaining above the phosphor means that there will be no degradation of the LED over time through oxidation etc. My previous attempt at de-doming ended up ripping off some of the phosphor, which resulted in a purple bulls-eye in the hotspot.
It would be nice if someone with a luxmeter could replicate this and check the results.