Center LED by soldering?

Hello,
Im working on this maglite build (i will maybe start a build log later). But im kinda stuck. I want optimal heatpath for the XHP50 im using.
So i was thinking about soldering the sinkpad to the pilar i made. Only problem is that i will not be able to center the LED well enough.
I have some artic silver 5. But im not sure if the heat transfer will be good enough.

So My question. Is there a good way to solder and center the led or will thermal past be enough?
The copper Pilar will be screwed down on a aluminium heatsink with thermal paste

Pic for reference:

Thanks
Dentillozie

Do not worry about the heat transfer with artic silver. Just polish both surfaces as much as you can and apply very thin layer of artic, press until paste hardens and that is it.

i would use thermal compound, easyer to swap LEDs later on if needed, will be easyer to center too.
also, soldering the sinkpad to the pilar will require a lot of heating wich could maybe damage the LED ( ? )

I put the star (without emitter) onto the pill and center it initially with the reflector in. I put markings on pill/copper star to make sure I know where to position it afterwards. After removing the reflector I put solder paste between pill and star and heat things up.

After letting it cool I’ll reflow the LED onto it and I can fine-tune the position. this has worked on 4 of my mods so far.

Okay, thanks all for the tips.
so the thermalpaste will not be a bottleneck, that would make this a lot easier.
i guess im going to user the paste and maybe put a small drop of superglue on the sides when its centered well.

I would say technically it would still be a “bottleneck” as in it would transfer less heat than the paths near it but with good contact you should still have enough transfer. Polish isn’t the term I would use though, you want to lap them to make the surfaces flat, this goes for the MPCB to pillar if you go that route and the pillar to pill. The sinkpad and noctigon are probably pretty flat but it’s easy to check. The pill and pillar might be less than flat which would really hurt your transfer. The easiest way to lap it is just just put some sandpaper on a piece of glass, wet sanding seems to work best. You can draw an X or color the part with a sharpie then sand a little and you’ll see it one part gets worn off before the rest that’s a high spot and it’s not flat. It’s not even that important that the surface is mirror like, as long as it’s flat.

Also I guess it depends what you aluminium heatsink looks like or maybe I’ve got the scale wrong but could you not center it good as you can then move the pillar on the aluminium pill for fine tuning the placement, guess it also depends on how the pillar fits into the reflector.

I stand corrected. I assumed that surfaces are already lapped. For me, the best way to lap them (using flat surface and sanding paper) is to draw number "8" in one continues motion (https://www.youtube.com/watch?v=-_0J54BhgiQ) and periodically turn the object by 90 degrees. Gradually changing the grit of the sanding paper towards the finest ones (2000 - 3000) you can lap and polish at the same time. Coloring the surface before sanding will help a lot because you can see the progress.

hmm. this seems like an interesting techique to try. thx for sharing!

Why not just use a Mag P7 heatsink instead? just lap the post to remove the centering ring and use a 16mm mpcb with AS epoxy…

http://www.candlepowerforums.com/vb/showthread.php?198785-P7-and-parts-****~~DSXPJ~~(800-900-lumens)-LATEST-quot-DELUXED-quot-P7-MAG-D-heatsink****

i was thinking about using one of these. but im using a LED maglite and the reflector would not fit without cutting if im not mistaken. also i don’t really have a big budget so im trying to make as much from stuff i have around.

The heatsink is an aluminium slug made from an old Intel heatsink. the copper pilar is made to fit into the reflector so i can focus and unfocus the light like you can with a stock maglite so i cant really use the pilar to center the led