Sipik SK68 Total Overhaul -01/05 All finished

01/05
All finished. Some beam shots, both on low mode as high washes out overexposed. Even then spot focus is still overexposed. Flood, wall switch gives scale~6’spread at 6’. Until this year I didn’t own one and had never had one in hand. The one I purchased had one mode and a fake emitter that died because I used it continuously for all of 15 minutes, mainly because of the hollow pill without even a shelf, just a beveled narrowing where the mcpcb floated loosely. In spite of all its defects and overall cheap construction I still like the darn thing and want to nudge it in the direction of its potential and to that end I’ll be doing the following to polish this little t**d:

Mod the pill to give it a copper full shelf, direct soldered XRE K-WC dedomed emitter and 15mm MtnDD FET+1 driver or possible just 6 X 7135’s.

Mod the switch to eliminate a mechanical connection in favor of a soldered one between the switch and a shorter spring. It’s already a variant of the Omten 1288 so this will put it on par with standard switch pcb’s. Also bring the switch button closer to flush with the end of the tail cap and eliminate slop in the switch, important in a multi mode light.

Bore and lengthen the battery tube to accommodate a 16650. This will triple liion capacity at the cost of ~12 mm extra length. Cover the brass extension sleeve with wood between the Sipik front and rear collars.

I’ve already posted the switch mod and some of the pill mod elsewhere but they belong here too as well.

The Pill Mod starts with boring the pill hollow out to match the OD of 1/2” copper pipe. Also a shelf stop has been mill in for no particularly good reason since I later decided to forgo using an mcpcb. Next I cut a short pice of pipe and brazed it to a piece of sheet copper. Trimmed it to fit and drilled it for wires. And pressed it in. Update 12/09 Tried to use the XRE collar as a guide to do a shave dedome but the material was too resilient to cut and broke away instead. No apparent loss of phosphor so I gave it a gas soak to finish the removal of dome debris. A small amount was left between the bond wires which I will leave alone tyvm.

12/15 update I desoldered the emitter from the star and ground off the contacts leaving only the heat pad Then I took some advice and twisted off the ring And after carefully picking away the reamaining glue I covered the top side contacts with tape Then I mixed up some JB weld and thinned it with a few drops of iso and carefully painted the substrate nudging the JB up against and around the bond wires Setting it aside to cure I set about prepping the pill to receive it. I used a 16mm sticky back XML insulator as a guide to scratch lines in the copper, shifting it from one side to the other to get a rectangle instead of a square. Then I tinned the rectangle, cleaned the flux, and painted it with some more thinned JB. The bond wires will probably break as soon as I fire it up but repeated testing up until the JB was applied confirmed the led operational with a neutral to warm tint.
12/18 reflow success Another bare cell test after reflow and it still works. Led is reasonably well centered (center of pill is somewhere within the die itself)

01/05
Ixnay on the XRE, output was dismal so I pressed out the copper a made another one with the height adjusted for a 16mm sinkpad with an xpe-2 R3 1D. I set the die height so that full zoom went just past square die to a more rounded spot. The driver is one if Richards 15mm 5x 7135 boards fully populated but with a simple 3- mode ui on the mcu. Pin 3 is grounded to eliminate strobe/SOS modes. Tail cap currents are roughly 90 mA, 510 mA, and 1.8A.

Tail cap and switch mods.

Here are the bits of the opened up switch along with the new short stiff spring and a brass disc to join it to the switch base. Here the spring, disc, and switch base soldered together. And the reassembled switch. The wider spring base required widening the hole in the press fit retainer but it all fit nicely The button cover is recessed more than I like So I milled the button cover shelf a tad. There’s still some slop in the action so I’ll add a drop of JB weld to the switch.

Tube mod. To both speed things up and aid in boring the pill true I bored the pill while screwed into the tube and when the pill was finished I removed it and continued until the tube was able to take a 16650. And now it’s no longer a host but pieces. The next step is to trim the outside of my he rear tube section so I set it up on a drill bit and mounted in the drill press with my hack saw blade. ! After a first pass The only way this can be done is by removing as little material as possible with each pass, any more causes side loading that can work the tapered chuck loose and cause serious injury, after several more passes I stopped before removing the flats completely and rotated it on the bit to make otherwise unadjusted passes to even it up and cancel the effects of any wobble. At this point it was time to make up the brass extension sleeve so I installed a cell and measured the gap.
I’ll use some brass to fill the gap. Then using the same techniques I’ve shown elsewhere I. Rolled .3 mm sheet brass into a tube with the section to fill the gap and temporary ends to hold the seam closed and even for brazing. After cutting off the temporary end collars(used the drill press spinning past the blade to support the thin brass from within), just enough room for an easy slip fit of the cell with no rattle. Then back to the drill press and sandpaper to bore out each half to fit over the ends of the extension. I used sandpaper strips only of the width needed to match the ends to avoid damaging the internal threads for the tail cap and pill. That’s it for now. The wood tube cover will get posted in the remaining reserved post.

Let’s look at some wood. This is a chunk of a Bay Laurel burl cap about 1 1/4” x 2 1/2” or so. Sometimes I even use the drill press to drill holes. But mostly not. Some lathe hacking. Up and down, wack the block over and up and down again, over and over. When I got to about 22mm plus I started sanding, alternating between hand sanding axially while turning the chuck by hand and spin sanding under power. Raised the grain a time or two as well then took it inside to seal it with epoxy sealer thinned with 90% ISO. Wall thickness is just under 1.5 mm. After the outside cures I’ll seal the inside as well. It may or may not need some more sanding inside to fit over the aluminum which is slightly larger than the brass. Sometimes the wood swells and gets bigger.

Not done yet this is just preliminary to the real finish work.

12/15 update not much here but did spend an hour or so wet sanding with 2000 and iso for lubricant to get rid of the remaining scratches. Then applied some more stain and rubbed that out. The picture is less blurry than it appears, the wood really is that speckled in detail.

01/05

One of the issues of the Sipiks is the weak and easily damaged ano and this one was no exception so I stripped it down to the bead blasted surface. You can see how the knurling spirals slightly rather than staying square to the tube. Once all the parts including the new SS clip and the burl sleeve had been wet sanded to 2500 I assembled it all together with Devcon 2-ton clear epoxy. The inner brass sleeve is a snug fit but spring pressure form that short stiffy is enough to push them apart otherwise. Isopropyl alchohol, paper towels, and q-tips cleaned up the excess and after cure another spin down the bore to smooth that a bit more. Even with a 65mm cell it’s still much shorter than my BLF A6. The finish has no visible scratches even under 10x magnification but I prefer the silky feel as is to a wax polish.

I’m here and waiting. :+1:

There is just something about modding SK68s that is just so entertaining. To turn a humble little cheapie zoomie into a little rocket all while spending vastly more time and money than was put into the original light. This makes me want to go finish that 2nd SK68 build that’s been a pile of parts forever. That battery trick is clever, totally hadn’t considered the thick walls of the SK68 could be bored out to 16mm.

Love the copper slug :+1:

It’s the only AA light I know of where the threads will pass a larger cell as is. Its only the cell bore that restricts cell size. There may be others as well but it’s these semi cheap lights that get my attention first. I know the fins are all wrong but this seems a GB project waiting for attention.

Bumpdate

What a pleasure to watch the process of this über-pimping of a SK68. :slight_smile:

WOW!! nice work. Whats the advantage of brazing the copper pill together as opposed to soldering it?

It’s stronger, a brazed joint is almost as strong as the base metal. Not as good as welding but far better than tin solder. A pill may get additional soldering for the driver or possibly a soldered in mcpcb and a brazed pill wont fall apart or leak solder from previous joints. If I had a metal lathe I would use it, this is the best I can do with what I have. Nothing wrong with others doing what they can with tin solder if that’s what they have.

Excellent work, RBD. Can’t wait to see the finished product! :+1:

Wow. This is looking real sweet RBD. Your patience needs bottling. :+1:

Sorry. It only comes as an herbal flammable though I hear with recent changes in the law it may get marketed to vapers. Just kidding, my supposed patience is only mislabeled OCD I’m like this most if the time. :person_facepalming:

Great work sofar, I wonder if you can recognise the sk68 after you’re done.

Fantastic job. Will be the most elegant Sipik 68 ever when completed! :+1:

Great job, fantastic mod all the way. Combining different materials results in precious, one of a kind gem.
Did you, by any chance, made a video or a tutorial on brazing? What materials (brazing rods, paste) do you use to join pieces together?

mad skills being showcased here. Lemme go put on some :nerd_face: & take some notes…