Suppose, just for fun, one wanted to build a small illuminated ring sort of deal, that would have to provide a small amount of light for several hours, but there's not enough energy budget to keep something like a piece of flexible LED tube light illuminated all that time.
Could you make it out of some kind of phosphorescent resin, maybe 3D printable, and then wrap it in bright LEDs to "pump it up" for a few minutes and then shut the LEDs off? Is there a particular material that would be good for an application like that?
The strontium phosphor that I've used was pretty gritty, so probably wouldn't 3D print well.
You can get the phosphor on ebay.
Why not mold it and stick the LEDs in before it sets? Hobby shops or Tap Plastics have moulding kits that have amazing fidelity. You make a model out of plastic or wax or anything, make a silicone mold, and cast as many as you need.
3D printing is usually silly.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
The strontium phosphor that I've used was pretty gritty, so probably wouldn't 3D print well.
You can get the phosphor on ebay.
Why not mold it and stick the LEDs in before it sets? Hobby shops or Tap Plastics have moulding kits that have amazing fidelity. You make a model out of plastic or wax or anything, make a silicone mold, and cast as many as you need.
3D printing is usually silly. =================================================================
SmoothOn has optically clear castable materials you could blend your phosphor into, and they have lots of good free how-to material on moldmaking and casting:
There's a Tap Plastics a few blocks away, and they have extensive mold-making and casting stuff. You can make complex stuff with microscopic detail. Or sub-microscopic. Silicone molds can make concave sides, within reason.
It looks like fun... I just haven't come across a use for it so far. It might be too messy for production, but would be great for making fixtures or prototyping injection moldable parts.
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John Larkin Highland Technology, Inc
lunatic fringe electronics
"John Larkin" wrote in message news: snipped-for-privacy@4ax.com...
On Tue, 29 Mar 2016 11:13:28 -0400, "Carl Ijames" wrote:
There's a Tap Plastics a few blocks away, and they have extensive mold-making and casting stuff. You can make complex stuff with microscopic detail. Or sub-microscopic. Silicone molds can make concave sides, within reason.
It looks like fun... I just haven't come across a use for it so far. It might be too messy for production, but would be great for making fixtures or prototyping injection moldable parts. ===================================================================
I was interested in trying some casting and had read most of the how-to stuff at smoothon, then I finally found an excuse at work to try it. We needed some custom vibration pads for a new prototype so I got a couple of test kits from smoothon and machined up a mold. Worked great, let me make small dimensional adjustments to adjust the tension and thickness to optimize the performance, then eventually it got farmed out to a commercial molder for production. Later we needed some feedthrough mounts/seals for some copper tubing so we made another mold and just cast those ourselves since the volume was pretty low. I wound up using PMC780, a shore 70A polyurethane, for both of those. Fun stuff. We also made vacuum traps and sold vacuum pumps so I scrounged a used trap and pump to do vacuum degassing, but if you were really going to do production a pressure chamber would be faster. I had the brilliant idea of using the $60 Harbor Freight pressure paint pot for that if you didn't already have a vacuum pot laying around (actually you could do pressure or vacuum), then did some googling and found at least 10 other people had beaten me to the idea, sigh. Ok, maybe brilliant was a stretch :-). All of our stuff was a tablespoon to a half a cup of resin at a time, so no real mess. Smoothon has pictures and videos of making large molds for concrete where they mix 5 gallon buckets of stuff at a time; now that can get pretty messy.
365nm UV LED's to charge the phosphor. Phosphorescent plastic machined to fit. Lots of sources:
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
If it's in your energy budget to shine light on the strontium phosphate, it's in your energy budget to have some dim LEDs going -- it probably takes more to "charge up" the phosphorescent material for a given time than to just shine dim lights.
I suppose I could be wrong if you're charging up some batteries -- but even then I'd bet money that a given volume and weight of glowing plastic is greater for the number of photons emitted than the same volume and weight of LiPo cell, or possibly even NiMH cell.
Having said that, UV light seems to be most efficient at charging up glow- in-the-dark stuff. Looking up it's absorption characteristics and matching that to various LED's emission characteristics would probably be a profitable pursuit.
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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Not a problem. Just mix in something radioactive, and the strontium aluminate will stay lit (almost) forever.
Radioactive Waste Night Light 3D Printing
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
There are or maybe were batteries that were a beta source in a cylinder. They made a few uA at something crazy like 400KV, which wasn't easy to handle.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
You imply you can't run the LEDs at low power full time, so by implication you require a phosphorescent material with above unity payback? Sucks to be you.
Above unity would be fantastic! Are they working on that?
It could also be that I don't have a power source available to run the LEDs full time. So I could store it in a battery, or maybe it might make more sense to make the emittimg material itself the battery as well. Just thinking out loud.
Above unity stuff is all over the internet, but I don't believe a word of it.
yeah, or a supercap, either is likely more efficient than the phosphorescent stuff, which fades exponentially, with electronics you can run it at a sufficient level full time, saving energy.
I meant, that you appeared to have an insoluble problem.
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