djozz's didn't-make-the-deadline-for-the-OLDIYfromscratchbuildcontest :-( entry

Hi, yesterday I finally had a full day at home with the family away, so I started on the overdue from-scratch-build. I entered the competition in the hand-made category, but did not have any serious time to build it until now. It is a complicated variation of a 9V light I built a few years ago with a Luxeon Rebel inside, and I have no idea if it will work in the end. It is all pretty small stuff (although not as small as what RufusBduck does) and I tend to always mess initially nice ideas up and come up with a sloppy end-result. So be it .

I formed the ideas when the contest was annouced in june and wrote up the design. The final design is the one with the arrow, some parts that i wanted to use are around it:

The terrible thing about this design is that it has hardly any heat-dissipation, and I could not think of a nice way to incude it because any seriously usable finning would make this light big and ugly. So I see this built just as a challenge; can it be done the way I want it?

And because I do not have abide the hand-build rules of the competition I can use these :

No fancy lathe-stuff or anything, but it does make life a bit easier :-)

Ok, I started off with some brass profile, measured the places where the holes would be, drilled the holes and hand-tapped the threading:

Unfortunately I did not have the 3.3mm drill bit for the M4 screwholes, so I used 3.5mm. The threading is quite loose now (here I go already, sloppy from start :-( ). Well, it is not unlike the threading of many chinese flashlights :-) . Here's a picture of the tapping in action:

I sawed the bit a wanted to use, drawed where the saw cuts should be, and fitted some leds in place (that is, on the outside, they will be on inside finally, and the two outer leds will be different ones). And it appeared I had done some wrong assumptions in the design: the Nichia219 was not 3mm square but 4mm, and the MT-G2 (it is a 2700K 90 CRI one) was not 10mm square, but 9mm. Had to correct some lines.

I did as many cuts as possible with the bandsaw, but I could not have finished it without the good old fretsaw :-)

This is the little 3D-puzzle that came out:

Or, with some fancy lighting:

djozz(2013) 'no title'

I had to make two raised bits for the 'screw switches' to make contact:

I sawed little rounds from some messing I had around and filed two notches to shape. I put some solder paste under the little rounds and used a small blow-torch to solder it together. then I sanded it flat and into shape:

So far, so good, and now on to something I wasn't comfortable about at all: the reflowing of the leds. I could not think of another way than just reflow everything in one go, but that would be nerve-wrecking, and I needed a separate carrier to assemble it all on, put it on the hotplate and keep everything still when removing it again. So I sanded a bit of aluminium nice 'n flat and off I went:

The block at the bottom is the hotplate (a converted 12V solder iron connected to a adjustable power supply), the block on top is cold, the assembly is on a aluminium slider.

For those who like to see me fumbling on the square mm, I made a video of the first attempt:

The result of the first attempt being that everything sticked together quite neatly, but when connecting a 9V battery just the two outer leds lit up (I was lucky that they did not blow). Apparently under the MT-G led it shorted. So I tried again and again, and an hour later it looked acceptable again, but when connecting the battery: nothing, no led lit up at all! I did check before placing the led which side of the MT-G2 was the plus (there are no visible clues on the led unfortunately), but now I doubted that, so I removed the MT-G2 and checked, ouch, it was indeed reversed, how did I manage that?? So I placed it correctly and went on with the fiddling and fumbling. Eventually I ripped off the solder pad of the Nichia, so having no spare one I decided on replacing it with an old XM-L from the spare-led box, being a bit bigger it would hold the pieces of brass together a bit better as well. Finally, after two and a half hours of trying and error and at least 6 heating sessions (I feel sorry for the leds ), I ended up with this, not quite as neat as planned, but it stayed one piece and looked like it could work:

And work it did (victory!):

The three leds in series create a nice moonlight, probably the only mode of which the heat can really be handled by this light .

So to bed I went, had a bad night without much sleep, and this morning, with a proper headache, I did some smelly chemical polyester casting on the assembly (to make sure the headache lasts for the whole day ). I first smeared the screws with (waxy) mold release agent and screwed them in place (to keep the screw holes open during the casting), I have never done such a thing before, I hope it works, and that I can get the screws out again after the setting of the polyester.

Now a little plastic container was made from an old blister packaging, and some polyester resin was mixed with hardener and stirred well.

A small layer was poored in the container and the led assembly was slowly placed.

And then slowly the rest of the polyester mix was poored (I did not need the syringe it appeared) and the container was covered with another piece of the packaging (polyester hardens less well near air contact).

As you can see the polyester has a refractive index quite close to the silicone :-)

And now wait for a few days to let the polyester harden well. In fact it may take me two weeks before I have the time to continue on this.

I really hope that the light is going to work in the end...

Awesome 3D Puzzle! :beer:
Interesting Idea with the resin casting, I am quite excited how that will work out! :slight_smile:

^ This! Cool stuff man! I can’t wait to see what the end result looks like. 8)

that is such a cool idea, I’m seriously impressed. I never would have thought of using the casing as the electrical circuit! Looking forward to seeing how the resin pans out.

Awesomely creative. Looking forward to following your progress.

Impressive work there Djozz! :)

Looking forward to see the end result. Take your time! No need to rush it! :beer:

And polyester resin huh? Very interesting indeed! Will definitely be watching to see what you do with this!

Nice work!

A Jenga light! Really cool idea. Congrats on getting the reflow done. That looked very tricky.

Very unique. I look forward to seeing the rest of this.

Very nice! Love the creativity of tying the power via the leds.

Thanks for the replies guys, but don't hold your breath too much, after a few hours of polyester setting it now looks quite a bit less pretty:

This is from the polyester shrinking a bit while setting, causing it to delaminate from surfaces. I had that in the Rebel build as well a few years ago, and that one kept working, but that led was conventionally wired up and the housing was one solid piece of brass, not with all those solder joints that can be ripped loose, and pieces of brass that can short against each other, I even think I see domes lifted off by the shrinking resin, uh oohh .

Fingers crossed...

It was tricky, and now thinking back on how it went I think it would have been much easier if I had taped the upper edges of the brass simply together with kapton tape

I was wondering how much that stuff would shrink. I believe there is some stuff that can be bought, that will shrink very little. The stuff that they use to do those scorpions and spiders inside the globes. I will have to look that up. I hope they still work for you when it's done.

What does I say. Cheating? I love it. I smiled the whole way through reading chapter one. I cant wait for chapter two. I must be on the wrong pain killers as you guys are so creative with what you do. Thanks for doing the build. Better late than never aye. Cheers.

Have you checked the thermal expansion coefficient of your resin? Maye the domes get pressen on again when you fire up the MT-G2. :wink:
(Casting electronics in resin can lead to interesting results. Still excited how it works out :-))

It would probably work if the casting was done on layers with a thinner layer at first.

This is really cool, & you have also given me an idea for a ‘standard’ torch mod in regards to the power circuit.

:beer: :beer: :beer:

This is the resin that is used for casting insects and stuff, it says so on the packaging. It might just stick better to the chitin skeleton of insects (and scorpions) than to silicone and brass...

That is great, even if the light fails, this has been both a good read and an inspiration for other mods. I'm a happy man .

And because I just had to know before carrying on I did a 'test drilling' through the plastic towards the battery poles and probed with the battery connected to two paperclips:

Still in business ....

Applause, hollering and whistles.

Drilling - resin - Jurassic Park!

Were you able to get any of the DNA out also :?