Never had a mule and thought it was time to build one. I’m Inspired by the new large format Convoy LED’s: LHP73B and NV1010 and 20A drivers.
Thinking of hosts like S21B (or variants) or s2+.
My question is how do you hold the glass lens in place without a reflector or TIR? I’m sure this community can help me with practical ideas.
I’ve built several. You can go as simple as a couple thick orings. There are some files to have spacer gaskets 3d printed. This is my favorite option. If you search convoy mule you can find the thread where one of the forum members was selling them with spacers. He also has the file link there for free. He is a great guy. I forgot his user name in here. He posts on Reddit too.
I may have had a misconception.
I imagined that the mcpcb would be in its standard position, and a spacer would support the glass lens.
I now see that some builds have a solid spacer (with slots for wire passage) underneath the mcpcb. A single thick oring could then support the glass from the mcpcb. This would also bring the led close to the glass making for less shrouding of the light and a more aesthetically pleasing look.
I wish I would have bought some of those spacers you linked to.
An alternate spacer solution is to get a bunch of MCPCBs, sand off the mask, and solder them together into a cylinder, but with wire cutouts inherited.
Yes, it’s best to have a spacer to bring the emitter closer to the lens. Mountain Electronics sells spacers for the S2+ and S6 for a triple build with an optic. You could use one of those and stack a couple mcpcbs on top. Solder them together if you have a heat plate.
As already mentioned and linked, my first attempt would be 3d printing a spacer.
You can use my CAD files and order the adapters from companies like JLC that tends to be a bit pricey if you’re not doing a whole bunch of them, but I bet you could do some extras and flip them to offset the cost though.
Stacking MCPCBs like some said, works but tedious to grind the mask off.
You can buy discs of either aluminum or copper and stack those: 1 16x2mm and 1 20x6mm disc is be enough.
I also did design a spacer that lets the MCPCB sit in its original position, but you lose a lot of light if you don’t move the emitter forward to the glass…
Let me know if you need any help with the CAD files 
-JB
Oh is the same question i need to know in this days.. thank you for posting it.
The high temperature of copper mcpcb is not a problem for the oring?
I’ve never had an issue. There are orings under the lens of every flashlight.
So you don’t use copper or plastic or other materials for this rings?
They have always the same measure?
I have not. Ive built mainly S6 Mules and a few others. You need to be a bit creative at times. Ive seen others use these though. I’m no expert at all so lots of my builds have come from some failures along the way.
Failure is not the problem..the problem is the right material and the right measures..i need for my UV mule 
This looks like the way for me.
Lots of copper for more heat sink!
