A Perfect Dedome?

Hi,

I posted on the “100% dedome” about an XP-G2 I’m trying to dedome in gasoline (see: X-ML de-doming method with 100% success?). The dome came off easily, but left a thin uneven clear layer of something on the emitter surface.

I’m wondering if there is something about XP-G2s that causes this (different construction)?

The dome came off clean, but left a bunch of gunk on the wires going to the die. When I did the XM-L the other day and broke a couple of the wires, gluing them back down with electrical liquid solder worked out ok. But this one has the wires on the positive side. What’s up with that? I was very careful not to break these and left some stuff there this time but still cleaned the rest up with needle pointed tweezers.

This T6 warmed up a bit, but it’s still a nice tint, slightly warm and I like it. Also made a handmade Titanium reflector for it which also turned out well, it now has a large spot with a good even amount of spill, with the blend being smooth and creamy.

Thanks for all the suggestions, gasoline rules!! :slight_smile:

ohaya - read the posts, never seen that before with an XP-G2 (residue), but mine soaked longer. I noticed in your pic one wire is gone - the ESD wire side wire, but supposedly that's not needed.

Hi,

Sorry to bounce between this and the “100%” thread…

FYI, I think the problem was not waiting long enough. I did a longer re-soak, and that residue on the emitter itself disappeared after that longer soak (about 6+ hours, I think). On the XP-G2, I think, as far as I could see, there were only 2 wires, on the side where there’s a “+” on the PCB. I know that I’ve seen references to an ESD wire on XM-Ls, but the XP-G2 looks like (the wires are tiny, and I can barely see them with a 10x magnifying glass) there’re only 2 wires.

Were you referring to the pic of the XM-L on the “100%” thread?

I dedomed 2 XM-Ls the last couple of days.

An XM-L T6 (from Amazon) went in my shorty STL-V6, and is now giving me 122 Klux,

The other XM-L U3 (from FT) is in my Jacob A60, and is giving me 87 Klux now.

Post #1019 in the other thread, close-up pic of the XP-G2 de-domed:

I just so happend to have a de-domed XP-G2 on a 20mm Noctigon around, and those 2 pts above the emitter in the pic above are connected by a wire on mine - yours appear to be missing the wire.

When you say “above the emitter”, do you mean “above” in the pic (i.e., to the “right” of the + side of the emitter?

I guess I lucked out then, because I don’t remember seeing any wires there through this whole dedoming exercise, but the emitter still works :)!!

Ooops, sorry, 2 connections just above the yellow pad - one connection is to the left of the trace cut (small connection), the other is to the right (large connection). The wire is supposed to connect the 2 connections but it's gone.

ESD protection. Not needed.

Took a C8 pill with Sinkpad still JBWelded in place, made about a dozen shallow cuts all over the dome, tied it to a copper wire and dropped it in the who-knows-how-old gas (at least a year old, from last year's lawnmower gas, has been used for around 15 de-domes and I forget how many reflectors that needed the orange peel stripped). An hour later...

...and after 5 minutes with my homemade plastic toothpick...

Scoring the dome with a razor makes it happen A LOT faster.

nice job with the clean up :smiley:

I’ll definately have to remember that little trick, would save a lot of time and eagerness and from the look of it provide the best result.

I use a plastic toothpick to clean mine up as well, it has tapered ends that come to a flat…works nicely for this. :wink:

Well done!

As I see it, the main purpose of removing the dome is to eliminate a converging lens because it reduces the effective focal length and therefore enlarges the throw hot spot.
So, maybe, the next step in that direction is to introduce a diverging element to increase the effective focal length and make a smaller spot. A common device of this sort is a Cassegrain telescope or microwave antenna. As a transmitting antenna, it focuses a finite size source to a small angular range, as we want for a thrower light.
Classically this would be done by putting a convex, ideally hyperbolic, mirror in front of the led and surrounding it with a parabolic mirror as usual. The light that misses the diverging mirror would form the spill, being out of focus for the main reflector. Other possible configurations would be adding a diverging lens to an aspheric or putting a diverging lens between a backwards facing led and a parabolic reflector. Something close to a classical Cassegrain seems the most compact.
The spill is partly focused, which may reduce the chance of blinding people near you.

yeah, nice, but who is going to develop all that, chinese, for their mas MAS MAS production :D right

A simple job doesn’t sound any harder than de-doming to me. Of course I am not doing that either, but I can talk.

The word salad is strong in this one, yes I agree muchly.

Not as much as in my OL DIY contest build… :wink:

I would like to thank Tom E on this thread…

Although I become your member just recently I was lurking this thread as a guest before…

Yes I have 100% rate so far and sometimes I don’t care to clean silicone residues and it still works perfect… I am testing each on aspherical lenses.

I recently tried to put fujik carefully around XP-G2 led emitter to protect those tiny wires from eventual drop or shock… I got that idea thanks to DBCstm and his black solder glue(page eight) that looks very interesting so I ordered some of that from ebay…

It is still on a shock test but I think Fujik can not harm to those tiny wires as when it cures has similar properties as pencil eraser we used so much in old school days…

Any idea of protecting led after de-doming would be much appreciated…

LED Seal - LED Supply.com

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I did another XPG2 with cuts all over the dome, dome floated off after 40 minutes, left it in for another hour and every bit of silicone was gone. Didn't even need to use the plastic scraper.

How about dedoming bare emitter before soldering it to al/cu base?

Having it mounted to something makes things a lot easier, even if you have to move it to a different board after the surgery.