[PSUBS-MAILIST] Emer Buoy brake and clear resin

[Justin Helland via Personal_Submersibles]

Just to add my single anec-data point, I filled an off-roading light with
epoxy and let it sit powered overnight and it seemed to work fine, although
it was less powerful than Hank's 200W, I think it was 60W. But the off road
lights have pretty solid housings with radiating fins, so maybe as long as
the light has enough mass in the housing connected to a heat sink you might
be okay. But I like Sean's suggestion of thermal epoxy, I bet if you could
get the thermal epoxy to contact the LED board as well as the housing you'd
be golden.

On Sat, Feb 8, 2025 at 10:50 AM hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Sean,
> I used casting resin, and not very thick, maybe 1\2 inch.  It would have
> been maybe 200 W  and it was submerged.  A test with a heat gun would be a
> good idea to start with.   You could make the epoxy extemly thin and try it
> with the thermal epoxy.   It only needs to seal out water.  Oil cmpensating
> has proven the components can handle pressure (1200 psi).   If Jon can make
> this work it would be fantastic.
> Hank
>
> On Friday, February 7, 2025 at 09:20:56 PM MST, Sean T. Stevenson via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> What epoxy did you use, and how powerful was the LED?
>
> I wonder about the possibility of a two part pour, where a relatively thin
> layer would be poured only between the emitter and the lens using a clear
> epoxy like this:
>
>
> https://mgchemicals.com/products/potting-compounds/epoxy-potting/clear-epoxy-resin/
>
> ...and then a separate pour could be done between the back side of the
> emitter / electronics and the housing / heat sink, using a thermally
> conductive epoxy like this:
>
>
> https://mgchemicals.com/products/potting-compounds/epoxy-potting/thermally-conductive-epoxy/
>
> Would depend I guess on how much heat the LED package puts out, the
> temperature of the surrounding water, and the efficacy of the housing heat
> sink.  Was your test immersed?
>
> Sean
>
> On Friday, February 7th, 2025 at 13:05, hank pronk via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> Jon,
> I tested an LED light in epoxy and it bunt up pretty quickly.
> Hank
>
> On Tuesday, February 4, 2025 at 12:39:54 PM MST, Jon Wallace via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hello folks, looking for some suggestions.
>
> 1) Are you braking your spool of rope for the emergency flotation buoy so
> that it doesn't unravel during normal operations or do you find it
> unnecessary?  If so, can you describe how you are braking your spool?
>
> 2) I'm testing a set of off-the-shelf 12v led lights (4 inch round) and
> was going to oil compensate them but now I'm thinking about just filling
> the entire void with a clear non-yellowing epoxy.  I don't see the units as
> having any useful or serviceable parts upon failure regardless of
> compensation method so sealing them permanently with epoxy seems like a
> viable and perhaps less messy method in the long run.  The units would
> require approximately 1.25 inches (31.75mm) depth of epoxy to fill them and
> my only concern is what effect the dry epoxy will have on the light
> emanating from the units.  Any thoughts?
>
>
> Jon
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