I think I have thought up a way to make 32mm (or any diameter) copper boards relatively easily and for all of <$2 each… for XML (and colour XMLs) and XPG, XR-E etc… this is all theory so far but I have listed below the basic principles. I will be trying this method once everything arrives.
Materials:
Kapton tape
Copper foil or copper tape (same thickness as PCB traces preferred)
32mm diameter 2mm thick copper disk (see note at bottom of post)
1. Starting with the copper core find the center of the disk and mark out where you want the LED to be as well as the pads for attaching wires.
2. Apply a layer of Kapton tape over the top of the copper core excluding where the center pad of the LED will be.
3. Cut two (or as many as there are LED terminals) copper foil strips that will reach (and cover) the locations of pads and LED pads… these will act as the PCB traces.
4. Position the copper strips and cover everything but the wire pads and LED pads in another layer of Kapton.
5. Solder up the LED and wires and your away laughing… wont be the strongest PCB but if anything brakes it can be repaired for <$0.10 and durability shouldn’t be an issue once everything is back together.
Cut and drill the required holes etc in them and then solder them together to get the right thickness.
Option two: someone on the forum (with the right gear) is kind enough (once this method has been proven or dis-proven) to buy a 32mm diameter copper bar… cut the required slots (for wires) into it and then cuts it into the right thickness disks… these then get distributed to those interested for a small profit to cover time and effort (should still work out very cheap).
Yes… but they don’t come in 32mm size and to create a board for them to sit in in host that takes 32mm boads is quite a challenge. Plus… this method (if it works) will allow you to make any format and combination (within reason) of LEDs directly bonded to copper which do not have a Sinkpad or Noctigon version.
E.g… XMLs with 4 colours under the dome… simply create enough “traces” to allow you to access each colour independently.
Ahh… Thank you. I was wondering why this had not been done before (and now I see it has). If you mind me asking have you tried this method with thinner copper and no center pad?
I have all the parts I need on the way so will post my own results (and pics) when they are here.
I did try with no center pad, but I felt that there was too much (air gap/solder, on the center) with the outer pads sitting on film, so I went with a center pad. I just used different thicknesss of the pads, so that with the film, they would all be the same height.
With the coming of copper stars, I have given up making these. If I want a larger pad, I just solder the star to another piece of copper, of whatever diameter I want and if the wire pads are an issue, I just extend them off the original pad with copper strips, soldered and pressed down, so they lay flat on the original pads and extend out to where I want the wires to be. Then I tape over the copper strips so the reflector does not hit them. That way I can get the reflector down close to the star if I need to.
Thanks. I have tried the method of using an existing 20mm board but could not get the wires / copper strips thin enough to work well with the reflectors I tested it on… mind you I did not have Kapton tape on hand which should allow the reflector to be dropped even further over the LED without a short.
As far as the size of the gap that needs to be filled with solder: with Kapton tape and very thin copper tape I should be able to get it to less then 0.15mm.
I’ve been wanting to do something similar in several lights. Was thinking of using copper sheet and sanding the tabs that will go under the electrical contact pads down to make level with sheet that would serve as the thermal pad.
Best of luck. Please update us on results/lessons learned if you make a go of it.
Yea, when I saw OL’s thread I immediately wanted to make an XPG triple copper board for my p60 builds. Seems like a lot of work and I never got around to it though.
