I did some thinking and some experimenting today. It looks like if I pack 3 18650s into the cell tube, there is space for a rod over 8mm in diameter between each cells around the outside of the tube, so if I can figure out something for that I could build a carrier pretty easily. I will have to find a way to do this that doesn’t electrically connect the two ends of the carrier. I think my best bet would be 5/16” (because USA ) plastic rod and to try to use screws to hold it to a copper plate. But we are talking some small screws here. I’d definitely need to have extra material for the inevitable destruction. Also need to figure out the correct length, and solder springs (Blue springs of course) and/or brass buttons to the plates.
I did find some screws I have high hopes for in my existing supplies. For safety, I will have to have an insulated edge on the + side of the cell carrier, because of contact to the battery tube. In theory it is anodized and “just fine” but I don’t trust that, especially with repeated insertions. Some of the anodization is already pre-worn or faulty to begin with
I think you’ll find there is no difference between 5/16” and 8mm, if it makes you feel any better about not being in some other country.
Okay, so I have done some planning. I will use copper discs at either end of the cell carrier. I can re-use parts of the original cell carrier (the end caps shown in the first image of post #3 ) to simplify my carrier construction. At least part of the end caps will be used to insulate the edge of the positive end of the carrier from the light’s body tube; part of the negative end may be used as well for fitment reasons. The way the carrier currently fits the tube, it slides into but not through the tube; I believe the negative end catches a lip where the tail-end threads are cut. I think I will use Blue springs on the negative and attempt to fabricate small copper buttons for the positive end.
For the tailcap, I’m going to attempt to coat the bare aluminum (see where the spring sits in post #10) with copper. This would allow me to solder a spring to it. I’d then solder either the existing, looks-to-be-brass button to the end of the spring, or fabricate my own from copper (and again, solder it to the spring).
If coating that aluminum works well, I might also do it to the driver-shelf and solder my copper heatsink to it.
Okay, I’ve ordered a 1/2” thick piece of copper that I’m planning to use for the shelf. Ebay seller that sells scrap cuts. So I’ll still have to cut a circle from it, and possibly sand down some thickness (hopefully not).
The copper sulfate for the copper coating arrived today, so hopefully I will get time to try that today. It shouldn’t take long, but I have to keep it away from my daughter (easy) and pets (a bit harder).
The fresnels also arrived today - 25, 27, amd 30mm focal lengths to try. Sadly it’s pretty much the last thing I can test - but what I can figure out is if I need a lens outside of them for protection (probably) and maybe order an appropriate UCLp lens
So I did the tailcap. I followed a process I was linked to on CPF. I cannot say I would recommend this process, though it did eventually bear fruit. It was slow, tedious, and I couldn’t really tell if it was working/going to work until it finally just did. The difference between “no visible copper” and “visible copper” was sudden; from there it was only a few more minutes to fill in the remaining bare spots.
Pictured: the copper sulfate dissolved in hot water.
I used the plastic spoon to stir it, not wanting to worry about my actual silverware. I also used a dry plastic spoon to scoop the copper sulfate crystals into the water.
The finished product. I actually cleaned it after this, but that picture turned out worse.
(Previously, bare aluminum.)
I was quite concerned with how thin the copper layer was, but it soldered well enough.
I did this with hot air, and it was a mistake. I should have used my hot plate. Way too much solder crept up the spring, stiffening it in an undesirable way. Fortunately, this ended up not matter. In the above picture I have also soldered the brass contact button onto the BlueSwordM Gen 3 spring.
And, reassembled to make sure everything fit.
This means that the new cell carrier I construct must be of equal or lesser length than the stock cell carrier. Otherwise I don’t think the tailcap will tighten down. Also, I’m really loving the champagne finish I ended up with on the body tube after I baked it (posts 11 and 12).
I did just barely manage to remember to pull the O-ring before I soldered the spring, and reinstall it for the test-fit.
Interesting! I will have to have a look at that process.
Yeh, that in itself is a very cool idea and perfect for your application. Even if it was slow, tedious etc… Nice progress
I don’t expect to see real advantages versus just replacing the spring, but I figured I might as well play the contact resistance game a little bit. And I wanted to try it, figured this was as good a chance as ever. If I really cared about the contact resistance I’d permanently attach the carrier to the tailcap. Then the only contact points would be the cells themselves and the positive end of the carrier.
I’m definitely not doing it for the pill/shelf. But I’m still considering soldering the emitter to the copper space I’ll be adding - even if only because I haven’t figured out a better way to secure it yet.
If you are determined, the most important step is the prepare the aluminum surface properly. Clean it with hot water & dish soap to start. I rubbed mine with steel wool next, and then followed the process instructions with an eraser. 100% of the challenge of this process is due to the aluminum’s oxide layer. So we want to be working on just the oxide layer during the process, and not a layer of dirt first.
Technically progress: I de-lensed the SBT90.2 I’ll be installing on this light. I technically have extras, but I was still sweating - it’s my first de-lens.
And it works
These shots are always tough. Hitting both contacts one-handed while taking a picture with the other hand… But worth it!
I’m expecting parts tomorrow, but I’m busy Sunday. Not sure when the next progress will be.
Okay, everything is here. The half-inch copper “slab”, some copper discs from Bopper (for the cell carrier), and the driver PCBs.
I am planning some quality time with a hacksaw, dremel, sandpaper&files; as well as my hotplate, hot air, and other soldering equipment. Should be fun - I just gotta remember to take pictures!
For scale, the drivers are 30mm diameter.
Update from the garage:
- Don’t drill a hole in a thin copper circle with a hand-drill. It will work but it’s bad. Pictures later.
- It might take me the entire rest of the contest time just to cut the half-inch copper spacer. All I’ve got is a hacksaw.
Drill holes through thin copper by sandwiching and clamping the copper between 2 boards. Drill through one board to copper to other board.
I may try something else using your technique, I have two spare discs assuming I don’t mess any up making the cell carrier. That should be easier, since it’s three very small holes and shaving down the diameter slightly. Not sure, possibly just drill several holes through the disc to fit the driver? I’ll definitely use it for the small holes for the cell carrier pieces. If I don’t end up happy with the driver ring, worst case I have some sheet copper and snips.
Anyway, today’s progress.
I started by tracing the inside diameter of the light’s head onto the copper piece I’m planning to use for the additional heatsinking in the head.
Next, I cut off the protrusions on the inside of the end-caps to the cell carrier. I’m planning to reuse these for insulation and fitment reasons; every other piece of the cell carrier will be rebuilt by me and will accomodate three (3) 18650s.
It’s tough to see here, but the copper discs as received from Bopper are shown here set atop the cell carrier ends. In both cases, the discs are slightly oversized to fit. I’ll have to shave them down, probably with my Dremel. (I didn’t do that today. Also, I took several pictures, and this was the best one I managed…)
Same deal with the size for the driver disc; at least this picture shows it better. It needs to sit down in the rim, not atop it.
So I started cutting the large copper piece. All I’ve got is a hacksaw - though I’m not sure what else I’d even be allowed to use. I can’t remember, does modified light category allow milling? I don’t have one anyway.
This is going to be a while.
So, to preserve my sanity, I alternated between sawing and doing other things. Like drilling the main large hole for the driver adapter ring. It… Well, see for yourself.
It’s not pretty. The driver fits it well enough that I could solder to it, and I got it mostly flat-enough-to-work, but… I may re-do this piece. We’ll see.
(I thought I had a picture after I’d “flattened” it, sanded it some, and dremeled some of the awful inside edge, but I’ve been having an issue where about half the pictures I take without unlocking my phone fail to save. I’ll have to take another picture the next time I’m out there.)
I also had to flatten the topside of the stock driver-shelf, to mount the new copper heatsink to it. I started by, as best I was able, flush-cutting the protruding features with a hacksaw. Progress pic:
It was not perfect, but I didn’t expect it to be. I got the big bits, ground down the major leftover high points, and then sanded it some. Good enough for me:
Some heatsink progress pics:
And that’s as far as I got today.
Hole saws never seem to leave as smooth a cut as I would like. I do find that drilling a large hole in thin copper works pretty good in soft stock using a carbide bit with a drill press and a wood sandwich. However, the sandwich method makes it difficult to pinpoint the hole center. And I have never tried it in thicker stock like 1/2”. The heat might kill the drill bit.
Man, you get TWO A’s for Effort here!! I’m really impressed with the copper deposition…that’s neat! And what a job for a hacksaw…with a fine-tooth blade to boot. Pick up a 14t blade sometime (or 10t if you can find one) because the rest of that hunk of copper will appreciate it on the next job.
Drilling copper is a whole subject in itself, with a chapter just for thin gauge sheet metals. That’s almost a double whammy there. Rigid workholding and a drill press is best so you can control feed pressure/rate, rather than a hand drill where you’re wobbly and can’t control as well, but the sandwich method works well sometimes. Good quality bit, sharp, is a must, and you can “dub” it slightly with a honing stone to help. If the bits you need are small and will fit in a dremel multi-chuck or something, that can do fine as long as you can keep it steady. Copper is one time that going fast and not using a lot of pressure can be the best choice (that’s a good way to ruin bits in steel, though). Drilling lead is just about as challenging.
I, um, may have warped the frame on my hacksaw today. So I might grab a new one anyway, and a 14T or 10T blade could be involved in that equation (thanks for the tip).
My impression of the copper is that it wants to grab. I don’t have a drill press (and I don’t know anyone with one to visit, either) so a handheld 12v Bosch is the entire equation here. Unfortunately. The hole saw is also… cheap. From a cheap multi-pack. I have a few regrets, but fewer dollars. My conventional drill bits are better but nothing special. Thanks again for the advice.
Grabby…yes. Depends a little on the particular copper alloy and state of hardness, and all the rest. Copper is a great way to break your old bits and buy those brand new ones you’ve been wanting for awhile. lol. Lots of ways to skin a cat but they all bleed the same way and are just about as much work. Enjoying the crafting on your project here!
My friend said I need a band saw and a bench (disc?) sander. He’s probably right but that’s out of my price range lmao. I put off the heatsink today to focus on the cell carrier, and procrastinate until the new hacksaw and blades show up. Like I said, I bent the frame on the current one. So, update to come tonight when I get time to sit down and write it and go through the photos. I will say I flashed Anduril to the ATTiny85 from my phone, and I don’t have pictures of that because the phone is the camera, but it was way easier than using windows.
Okay, so like I said I set out today to work on the cell carrier, since I didn’t really touch it last time.
I began by using a dremel to reduce the diameter of the copper discs that would go into each end of the cell carrier. The inner diameter of each plastic endcap was 40mm, and the discs were a bit over that.
Progress was slow. But I eventually got them to fit. The first one:
And the second. The hand-made nature is pretty obvious in these. I also sanded them due to edge burrs.
I had some ideas about marking out where to drill the holes but things didn’t really pan out very well as you’ll see later.
My drill bit was up to the task, though. Went pretty easy. I applied WD-40 to each hole on a whim. I tried to go fast with low pressure, and it did fine. I also countersunk the holes.
To match the pattern for the second disc - by this time, having realized my patterns were not nearly as good as I’d hoped - I simply clamped to drill the first hole, then put the screw right down into that hole to keep the discs aligned. Worked great.
Next I cut my plastic rods to length with my hacksaw, which was still up to this task at least. I was able to hand-drill holes in… okay, near the center? In the ends, without breaking out of the sides, anyway. It’s fine. I promise it’s fine! I tested the first rod.
I’m going to need to countersink more…
In the process of assembling the carrier, on the third rod I kept breaking a screw on one end. This happened twice before I moved to a larger screw size (and had to make bigger holes) for this last rod.
I needed to make a small “button” of some sort for the positive contacts, since this carrier wouldn’t be long enough for springs on both ends.
Enter copper sheet and snips. Easy peasy.
Cuts like butter. Then I figured, if I’m gonna reflow the springs and buttons on the hot plate, I may as well do the driver, right?
All pasted up and ready to go. This is how I lay out my drivers, by the way:
My favorite stage of reflow is when the paste looks like this:
Alright, everything has flowed. Who can spot the issues?
The problems are circled in red at this link. And fixed.
So I had to trim down the external diameter of the driver ring I cut previously. I decided to try the snips…
I should’ve done the cell carrier discs this way! It fits:
And I marked where to drill for the screws with a pencil (but I did not get to drill them today).
And finally, I glued the end caps on the cell carrier. I test-fit a 30Q and it’s kind of tight (it nicked the outer wrapping on the head), so I will probably basically permanently install the VTC6s I ordered in this light.
Big update today, lots of progress. I’m quite pleased. The cell carrier is glued with E6000 and will cure for 72 hours. Hopefully that holds, otherwise I have to buy some 2-part epoxy (JB-weld or equivalent) and even worse, smell the stuff when I use it.