…or copper possibly…
Great tip. It got me thinking… how about freezing that container with water before use?
I really don’t see any benefit there… I put what I soldered together in the water and after it stops sizzling, I just set it down and leave it in there for a little bit. Honestly, after being in there just a few seconds it is cool enough to pick up.
Yeah, check that one. It sure looks like it isn’t bridging any more.
Maybe not, but the solder is.
I’ve dealt with some real hot ones in the past and have moved away from anything that can cause steam. I have a 10lb slab of copper that I put out on the balcony before hand. (It’s winter) copper absorbs cold as well as heat. I just move the heated copper onto the cold slab and it cools instantly with no worries of scalding steam or exploding ice.
I can’t see it that well. Is it bridging? It looks like there is a dark line where the “bridge” would be. I wouldn’t want to trust the operation of a hot triple to what little solder there may be in that gap.
I’ve never had any problems with the steam. It you immerse it slowly you will be fine.
Guess not. I haven’t done your method myself so I have no idea how much it sizzles. Was just thinking it might be a safer way if one is concerned about getting the LEDs wet.
Maybe things have gone fine so far, but when modding, S**t happens. Maybe next time the copper will be twice as hot and things go a little differently.
I think the safest way is to place a hot piece of metal onto a cold piece of metal. It doesn’t have to be copper, just a hunk of metal you threw in the freezer beforehand.
Even then, you may still end up dropping that hot hunk of copper in your lap while fumbling with your tweezers.
Actually, I often do cool the hot piece off to some extent by placing it on a cpu heatsink I have sitting right by where I reflow things. If it’s a pill or something larger (not a mpcb) I’ll set it down on the heatsink for a bit first, then cool it off the rest of the way by water. If I’m reflowing an led onto mpcb, I just put it right on the heatsink and it’s cool to the touch in not more than a few seconds as well. The issue I have with the copper spacer/ brass pill is that there’s little thermal mass sitting on the heatsink or cold hunk of metal or whatever, and it takes too long for my liking to cool. More than anything I want to resume working on it so it’s fast that way. Also for transporting things I use pliers, not tweezers. That’s not saying I haven’t dropped things tho, bad things can and will happen while modding. I’ve become quite good at ruining xpgs through the dedoming and reflowing process!
Testing for continuity says everything is bridged correctly. However, I do believe there is a gap of solder that is connecting the bridge. IDK if this is a problem or not. I may try to just move it a bit with my iron.
It also test without any shorts. I know though! I sure looks shorted, but its not.
When there is emitters involved, I was under the assumption that the work needs to cool down slowly for about a minute or so?
If it’s a fat copper heat sink I just get the feeling that it takes too long.
Most of the time, I don't solder a mcpcb to a heat sink, although I used to. I use Arctic Alumina or Arctic Silver thermal adhesive. If the bottom of the mcpcb and the top of the heat sink are finished to a mirror finish, then thermal adhesive works well enough. It's used in a super thin film, so it basically just holds the two together. Soldering a mcpcb is a pain in the arse and I don't think there's enough reason to, if the adhesive is used properly. A film so thin that it is somewhat translucent and you can see the part under it, is about right. Never had an issue using it and it makes it easier if you ever have to take everything apart again. Also, drilling and tapping for machine screws, will do more for making great contact between a mcpcb and a heat sink, if there is room. Then thermal paste can be used, instead of adhesive.
In the balder triple I just finished, I didn’t solder the the mcpcb to the heat sink. The tolerances were to tight and might have jammed everything up if it was slightly off. Since the heat sink was being screwed in tight against the noctigon from the bottom against the head of the light, I just used artic silver paste. It does just fine. Nothing worse than soldering down your noctigon and finding that the optic fits cock-eyed in the head and have to either de-solder or file down the optic.
That’s good to know. I just did it because most of the triples I have read about have had the mcpcb soldered to the heatsink. And it “feels” like it is superior even if in reality it is not. Idk if that count for something or not? Probably sound silly to the veterans though
Well, if you solder it you can be pretty confident that the thermal interface between the MCPCB and the pill will remain intact. With thermal grease/paste/etc you need to ensure that adequate clamping force is keeping the MCPCB and pill in contact with each other. Some of the thicker grease feels pretty solid until you heat it up, I’ve been fooled by that once or twice on the bench. Next thing I know the MCPCB is dangling by wires (and roasting) instead of resting on a heatsink. That brings us to our next thing: if you want to make sure that you get full contact across the bottom of the MCPCB (which isn’t strictly necessary!!) you’ll probably want to solder. Clamping the MCPCB by the edges often warps stuff so that you don’t get metal-to-metal contact in the middle. Again, you don’t necessarily need that contact at all, but soldering should dodge that bullet. Since I’m not one of the high power build gurus I am far from the final word on this.
I definitely see where Ouchyfoot is coming from here RE: tolerances. I’m not sure how some of our prodigy members are able to solder stuff together and have it fit the way they do. Mad skills I suppose. With some lathe-turned circles I suppose you can get things to self-center correctly while soldering - at that point it should just be a matter of making sure you used the “correct” amount of solder.
I’m not suggesting soldering is bad or pointless or that I never do it, in fact it’s a 100% guaranteed heat transfer method. I’m just saying that it isn’t necessary in all cases, and can be a source of Murphy’s law.
Nothing worse than soldering down a Noctigon and finding the LED is off center in the reflector. A 16mm noctigon and thermal grease with the reflector cranking it down onto the heat sink will transfer heat just fine.
I’ll probably be soldering a triple to a heatsink in the next week or two, but only after I’m sure that’s the mod I want, with the LEDs I want. Murphys Law is real. The mCPCB could end up missaligned, or an emitter no longer works. Heat up the whole thing to fix that emitter and the other two don’t work. After all that heating, maybe an emitter will decide to die, or you start getting solder bridges under the emitters. The dielectric layer could start delaminating.
Like I said, soldering is 100%, I’ll still do it myself sometimes, but beware. I’m just mentioning these things because every one of them has happened to me at one point. I think the first time I did it, all of the above happened on the same mod.
Wight/ouchyfoot thanks for your input. I think I now have a good idea of when soldering is nessessary. It’s probably a judgement call for each build. On a build with tight tolerances, soldering may be risky. On a build that has good mcpcb to host contact and has good pressure against the mcpcb from the reflector, soldering may not be nessessary. On a build without those things, the heat transfer concern may merit soldering the mcpcb to heatsink. All of these factors will influence a judgement call for each build. I believe this is what I am hearing from your posts above.