XP-G dome defects- Mtbr.com
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  1. #1
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    XP-G dome defects

    Has anyone built a light using an emitter with a visible defect in the dome? Out of a recent batch of LEDs from Cutter, 2 have issues. One has a crack that extends about halfway across the dome and the other has small, but noticeable air bubbles in the plastic. I don't have a camera with a decent macro ability, but I'll see if I can get an image posted.

    If any of you have tried this, was there a noticeable defect in the final beam quality?

  2. #2
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    I have had various emitters with lump, bumps, cracks, solder burns, etc. I don't notice anything in a beam as artifact from these imperfections.
    You may be more observant than me though since you can build smaller lights than I can.

  3. #3
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    Thanks OD! That helps me feel better about using them versus trying to pursue exchanging them. Solder burns??

  4. #4
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    1) Iron too hot makes flux sizzles/pops and flux hits dome melting small gouge.
    2) Trying hold wires, solder, iron, and light and end up singeing dome with tip of iron.
    Good times....

  5. #5
    A waste of time it is is
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    OD, THIS is my best friend during assembly

  6. #6
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    you may see stuff like that if using aspherical optics and focusing them but I have never seen the effects of criminal damage like OT`s in the beams and am guilty of all his crimes too .

  7. #7
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    Quote Originally Posted by odtexas
    2) Trying hold wires, solder, iron, and light and end up singeing dome with tip of iron.
    Good times....
    Oh, I do know how easy that would be to have happen. Getting the wiring in my microlight took all the skill I could muster to keep from messing it up.

    This next light I'm starting is going to be even tougher as the bores for the reflectors are 18mm diameter at the top, tapering to 10mm diameter at the bottom, and are 18mm deep.

  8. #8
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    Butterfingers followed by a quick recovery, saved a drop to concrete for one light during construction BUT tore a pad off an XP-G 10 mm round. Soldering to what lead remained overheated the die at one corner. (So I learned to order for some loss during construction. ) That is the one I dedomed like they do the XR-E's to get a narrower beam with aspherics. It has a triangular yellow-greenish patch when aimed at a surface within a few feet. On the road, where it is aimed in the 50-100 m range it is not noticeable, and the light output with my cheap meter compared to the other light indicates all is well that way. I cut as smooth as I could, but the fill material behind the dome has tiny ripples from the X-Acto blade. They do not show. I am planning on trying an XP-E R3 in that position, partly from curiosity, partly from the fact I know it isn't as it should be. Experience: what you get when things don't turn out as planned.

    Another XP-G has a line like a hair that is only seen at certain angles. It doesn't show either. I suspect that individual XP-G differences in output per watt are at least as big as any effect from minor dome defects, if not an order of magnitude larger.

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