Thought I’d give it try instead of just slicing it flat. It’s hard to tell from the picture but it has about a 1/2 inch radius. Unfortunately, it’s too thin for refraction to have much of an effect so the apparent size difference from a flat dome really isn’t significant. Next time, I’ll make it taller and try to reduce the radius.
I used a bent razor blade and shaved away tiny bits while constantly turning the LED then, ever so lightly, sanded it smooth while frequently flushing away the minute silicone bits. I’m not sure if I’ll finish polishing it anymore until I get another MTG2 to shave flat and compare beamshots.
Here’s an MTG2 (right) which I carved out about a 1/4” radius concave and kept it further away from the phosphor. The surface of the sliced dome (left) is actually much rougher but being cut so close to the phosphor, it looks cleaner. So far, it appears about 12% smaller (4.3mm vs 3.8mm) which makes it 12% brighter per area than a slice or dedome but with a reflector, it probably won’t have any advantage because more than half the dome is still intact and leaks magnified light to the sides. If that part could be made reflective, I believe an aspheric lens could take full advantage.
Yeah if you used a router bit, like pinkpanda3310 suggests, you might get a more perfect concave surface. And, if you could mirror the sides to work similar to a Wavien collar, and use an aspheric lens, like you said, the increase in throw could be considerable! Great work! Keep us posted!
I have done this before, but wasn’t happy with the results. Yes, the hot spot was smaller, but there was a green ring around the hot spot created by what’s left of the original dome (around the perimeter). I did use a router bit mounted in a drill press. It works better if the dome is cold…fresh out of the freezer cold.
When you get ready to polish, I found the easiest and best way is to use a Q-tip. Cut one end off and mount the Q-tip in a drill. Put a drop of ‘plastic polish’ into the depression and use the drill/q-tip to polish it. Again, the polishing works best if the dome is kept cold. It makes the material harder and harder materials polishes better than soft materials.
uh i dont think you can remove the dome completely from a MTG2 as the phosphor will come up with it…let alone removing the dome completely and replacing it does nothing…
What smaller lights was suggesting is to make a concave “dome” out of silicone using a mold, so that it would be smooth and clear. And the MT-G2 has been successfully de-domed before, but that won’t even be necessary. If you just slice it flat, you could mold the concave “dome” (what should that be called?) onto it cleanly.
If I can I’ll try it with an older XML first. Drill small hole just short of die surface and follow with a counter sink bit. I’ll need to do before and after beam shots as well. Should be done with this by 2525. Just a wag but my thought is that the with a curved shape(convex or concave) refraction takes place leading to wavelength separation and tinged carona but a cone shape might be predominantly reflective instead maintaining a more even color distribution while also causing more light to hit the reflector surface. While I wouldn’t expect it to reduce apparent die size the hope is that it would reduce spill and increase spot intensity. Something to try anyway just to see how other shapes besides dome and flat affect beam profile.
