my light will use a cable/12V plug for power from external source.
I want to pot the driver for heatsinking and to protect from physical damage (I don't mean add a potentiometer). There's no pill in this light (the emitter is mounted direct to body) so there isn't a dedicated spot for mounting the driver, like there is in most flashlights.
Initially, I thought I'd put the driver in a copper pipe cap (and leave only the contacts exposed) then fill that w/ thermal grease or adhesive, but...
the emitter is not electrically isolated from its base, and I didn't attempt to isolate it when mounting because I wanted maximum heat transfer. So, the body of the light is positive, (yup...reverse of what is common) which complicates matters a bit...
Just to keep you guys posted: I screwed the SST-90 on a solid piece of Aluminium, thermal paste inbetween. No more heat problems!
I'm also thinking about making my own battery packs: two 3-in-series parallel. I'll make a mold in which I put the batteries, and fill it up with expoxy. I'm aware of the fact that the liquid epoxy is exothermic, but I don't think the "heat" would destroy the batteries.. Any ideas on this one?
You may wish to explore other options for the battery pack than epoxy. With your 3S2P array, you may need to replace one or more cells at some time. A less-indestructible material may serve you better in this case.
shrink wrap would be cheaper - like these http://www.ebay.com/itm/2x-TENERGY-LiION-18650-11-1V-4400mAh-BATTERY-PACK-/190573053972?pt=Radio_Control_Parts_Accessories&hash=item2c5f0a0814
Mm, both the tube with gland and shrink wrap sound like good ideas.. How likely would it be for one or more of the batteries to die? They should be rechargeable like a 1000+ times, and since the average diver only dives like 20-30 times a year...
If it were me, one would die right after I shrink wrapped them.
You can find 18650 holders. I have a few of these - I'd go higher quality. http://www.dealextreme.com/p/11-1v-3-x-18650-battery-holder-case-box-with-leads-100996
and put them in a pvc pipe, otterbox, etc
but, one plus to the prebuilt RC packs, is they can be had w/ PCB protection built in...so that you're less likely to end up w/ a nasty toxic smoke and incendiary grenade
I just did a test pouring: I melted whatever aluminium scrap I could find to make a solid piece. Test succeeded! Now I'm going to make a rudimentary mold to cast the "big" body parts. I'll keep you guys posted.
Have you decided on a reflector or optic on the sst90 to get the beam angle desired. the narrower you make the beam, the brighter the light will be. A 45 degree optic or reflector will do nicely. Did you leave enough room in front of the led for one ? let me know, as I can recommend a few.
I think you can get good results w/ that reflector. That is what was used in this light. But since you bought the reflector, maybe you've already seen it.
I've been googling casting aluminum but haven't tried it yet. Did you build a foundry or do you just have a good torch? Maybe I should start drinking beer from cans instead of bottles :)
A while ago a decided to start making my own knives. Not just cutting and sharpening sawblades, but the real deal. Blacksmithing, forging, forge-welding steel. So I needed a decent forge. Which I made. Google and YouTube are really my friends to find out how to make new stuff.
It's just an old propane tank, isolated witch 1400°C insulation (~kaowool). An adjustable gasregulator, a reversed vacuumcleaner and a burner (flattened piece of metal tube).
The picture is not my forge, although the 2 forges work exactly the same. I'll take some pictures of my shop later this day/week.
Thanks btw for verifying whether I bought a decent reflector.
Nice - yeah google is awesome. I'd be lost, at work and at home, w/o it...
Are you casting just the heat sink and light parts or did you do a battery holder that way? An aluminum battery holder would be awesome. I imagine it would help keep the batteries cooler than plastic or pvc, especially in a dive light.
I'll be casting the body parts, not a battery holder. I'm still considering the epoxy way of making my battery, which makes a battery holder redundant.
I've done a fair about of molding (stock bedding, actually) with acraglas and devcon.
Those are kind of expensive options.
Here is a site with the best prices I've found for quality vinyl ester resin and urethane expanding foam. I haven't tried their other stuff, but I bet it is just as good.
I think you'd be surprised at the temperatures that epoxies can reach. I can't say whether it'd be safe or not, but I know it can get hot enough to be unhealthy for your cells. Personally, I'd use pipe w/ a release agent on it. Remember, some batteries can be a little fatter than others.
BTW, add filler to your epoxy and save some money :)
