[PSUBS-MAILIST] Oil Comp Lessons - so far

[Alan via Personal_Submersibles]

Jon,
It looks like the fluorescing material that they commonly use on COB
( chip on board ) LEDs. In the attached picture is one of my LEDs which
is really 70 LEDs imbedded in that yellow fluorescing jelly stuff.
They have tiny microscopic wires that the jelly covers & protects.
You can just see them with a magnifying glass.
Btw each individual LED on a COB is normally 1 watt & you can tell the 
Watts of the COB by multiplying the rows.
Interesting that they came unfixed in the oil. I did experiments soaking
various plastics in oils & if they didn't show detrimental effects after an hour
or a day, they could still deteriorate over a week or longer.
Silicone seems the best option.
Alan


> On 15/08/2019, at 2:30 AM, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> So, back to oil compensation of RoadShock LED fixture for a moment.  It's been a little over a month since I tried using Marvel Mystery oil in this fixture.  As you may recall, the oil seeped through the wiring and was leaking through the socket.  I removed the oil and set the lamp aside for another time.  
> 
> Yesterday I decided to poke around with it a little bit and see if I could remove the LED PCB from the housing as well as determine where exactly the oil seeping was occurring.  When I set the unit aside a month ago I left a trace coating of oil in the housing since I just dumped out the bulk of it without thoroughly cleaning it.  It turns out that the "lenses" attached to the LED (remember there are four of them) all popped off while I used a paper towel to absorb some of the remaining oil film that was in the unit.  These lenses appear to be silicone.  They are a soft spongy rubbery material that I can poke and indent with a small screwdriver, but recover to their original shape.  Obviously translucent which is why I assume silicone.  See attached photo.
> 
> While the silicone itself seems unaffected by the oil, I'm assuming the oil affected whatever adhesive was used to attach the lens to the LED face.  The light is still usable, just that what ever beam was created by the silicone lenses obviously isn't there anymore.  Just a blob of white light, but frankly it doesn't look too much different than the pattern I saw with the lenses attached.
> 
> I don't see any degradation in the wiring insulation at all that was exposed to the oil.
> 
> Alan, I don't know if you recall, there were two screws attaching the PCB to the aluminum housing and I thought perhaps that would allow easy removal of the PCB.  It doesn't.  I couldn't get the PCB to come out and assume it must also be expoxied to the housing in addition to the screws, or perhaps the screws are there as a grounding conduit?  not sure...in any event I would have to destroy the PCB to get it out.
> 
> Anyway, thought this was interesting to post a follow up.  My guess is that under working conditions these lenses would have eventually separated from the LED face and changed the light pattern.
> 
> Jon
> 
> 
> 
> 
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