Waterproofing by embedding in epoxy
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It would be nice if, instead of for art, there were also some kind of cheap chinese kit for embedding sensors into epoxy in order to waterproof them:
https://www.youtube.com/watch?v=yc4zsbbyZxQ
It's cool that the container that the epoxy is poured into can be peeled off so easily.
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There should be no reason you couldn't encase your project in Epoxy. People put electronics in epoxy all the time. the one thing would be heat dissipation on components that may need it.
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Don't forget to use epoxy in a well ventilated place (fumes are toxic) and to wear proper gloves as repeated skin exposure to epoxy will lead to some really bad allergies. See first comment in here
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@kimot Except In the instructable you posted he made the container out of card stock which did not appear to peel off but instead he ground it off with a belt sander.
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@nca78 said in Waterproofing by embedding in epoxy:
Don't forget to use epoxy in a well ventilated place (fumes are toxic) and to wear proper gloves as repeated skin exposure to epoxy will lead to some really bad allergies. See first comment in here
Yeah, I've often wondered if it's actually safe even after curing, because unless you are incredibly accurate in measuring the chemicals and incredibly thorough in mixing them, won't there be unreacted chemicals leftover that are still toxic? Maybe the dual-syringe packages with the mixing nozzles at least reduce both those risks, so that's what I'm leaning towards.
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@neverdie If you want easily removable and reusable moulds then go for silicone moulds. These can be either the type specifically sold for epoxy moulding, or silicone trays for baking (but don't let Mrs NeverDie catch you!).
The most economical way of using epoxy is to but the large containers of liquid and hardener. The epoxy adhesive (Araldite type of products) tend to be more viscous and harder to mix properly in large quantities.
Take a look on eBay at what's available.There are also other potting compounds and rubberised paint products that are specifically designed for waterproofing electronics and may be a better option. Search for Plasti Dip or TRV Tropicalised Varnish.
Pete.
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Have you seen the Cave Pearl project?
Loads of detailed discussion of the challenges of underwater sensors, I love it:
Thecavepearlproject
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Great Scott! channel did a few great videos on this:
https://www.youtube.com/watch?v=pGLUsQozT94
How to Waterproof Electronics || Nail Polish, Silicone, Potting Compound – 07:49
— GreatScott!(I have been using cheap clear nail polish from dollar store, and it seems like it works for moisture protection... not using for submersion however.)
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I've taken to spraying my battery contacts and electronics with a conformal coating as further prevention against corrosion. Presently I'm using Corrosion X for indoors and Corrosion X HD for outdoors. I don't have long term data about these products, so I consider it a bit of experiment, but without them I have noticed over time some amount of metal rusting in the past, especially near the battery terminals. I suppose tabbed batteries would be best, but I would probably still spray them anyway as belt-and-suspenders.
In the past I looked into using two part epoxy as a conformal coating / potting material, but that tends to get expensive in a hurry, and it's not reversible either. Hopefully the Corrosion X lasts well enough without having to re-apply it.... The longevity of it is what I'm most unsure about. Is there a better conformal coating to use? I just recently applied the Corrosion X HD to some outdoor solar garden lights as a kind of torture test, since they aren't well sealed and the rust/corrosion tends to eat away at the Chinesium like clockwork if nothing is done to mitigate. After a year or two outdoors, I should have a good idea as to whether it's helping or not and get some impression as to longevity.
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If its jsut purely for waterproofing and not asthetics I wrap them in heat shrink and seal the ends with hot glue I have all sorts of sizes of 3:1 heatshrink all the way from 1" wide to 8" wide.
Here is my gateway thats sits next to me(took photo right now) the ends are not sealed but you get the idea
https://i.imgur.com/7dR4xZT.jpg
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@Dreded I'm not sure about the hot glue part of it, but you're right: I notice the heat shrink tubing with the glue on the inside is advertised as "marine grade". Perhaps you could simply clamp the ends when the glue is still hot to make a "marine grade" seal.
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@pragtich said in Waterproofing by embedding in epoxy:
Have you seen the Cave Pearl project?
Loads of detailed discussion of the challenges of underwater sensors, I love it:
ThecavepearlprojectThe cave project is great. He did find a waterproof epoxy that works for him, and I think by now he's pretty much proven that it's bulletproof, even when continuously submerged underwater.
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As long as you provide ventilation, epoxy is your go-to. It's a good idea, go with it!
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@NeverDie said in Waterproofing by embedding in epoxy:
@Dreded I'm not sure about the hot glue part of it, but you're right: I notice the heat shrink tubing with the glue on the inside is advertised as "marine grade". Perhaps you could simply clamp the ends when the glue is still hot to make a "marine grade" seal.
thats what I was meaning, I put the hot glue in and clamp it with a vice while it cools usually leave an extra 2" of heatshrink tubing and cut it off after the clamping to a reasonable length, I figure the vices teath leaving bumpy marks might help the seal... for something I just am putting out in the weather I often just squish it by hand depnding on the size of it.
I have made lit up pool toys this way and no issues so far with over a year of kids tossing them about.
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@Dreded
FWIW, I don't have direct experience myself with longevity and durability of heatshrink + hot glue, but one of the YT channels I follow does. Julian Ilett has a custom-built pwm solar charge controller which he made small production runs of, and started having failure issues with this method, as these are exposed to outdoor environmental conditions.
Autopsy: Faulty PWM5 Solar Charge Controller – 16:40
— Julian Iletthowever, I would think that "potting" or filling the heatshrink openings with "RTV" (i.e. room-temperature vulcanizing) silicone sealant. This stuff is used on marine and aircraft applications to completely waterproof stuff.
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@Jens-Jensen Thanks for posting that video. I wonder if in Julien's' case there might have been moisture penetration through the insulated wiring ingress points. If the outer insulation coating were sufficient, then waterproof wiring wouldn't require that sticky goo they put underneath it. Once it gets inside the "sealed" enclosure by travelling through the insulation, it can do its damage with nothing to stop it. So....maybe if Julien had applied something like Corrosion X or some other conformal coating and then sealed it all up it might have lasted longer. I think extending the heatshrink to completely cover the wiring so that only the metal connection terminals on the end are exposed may be the only way to prevent the moisture ingress, assuming the heatshrink stuff really is moisture proof.
In contrast, I suppose in the Great Scott epoxy filled approach, even if moisture does ingress through the wiring insulation, it has nowhere to go since all the electronics are protected with the epoxy.
For those who don't know: something can be waterproof without being moisture proof. Housewrap would be a perfect example of that, as would gortex raincoats. So, having something that's waterproof rated doesn't tell you enough information. i.e. even something rated at ip68 could let in moisture. A lot of plastics are waterproof, but not moistureproof. Also, from what I've read, the most commonly used hot glues are not moistureproof.
And of course if you have any air at all inside, the moisture in it might condense into water if it gets cold enough.... So, I think Julien's setup is prone to eventual failure for a whole host of reasons in addition to those that he mentioned: the host glue, the wire insulation travel path, and the trapped air.
I did once try an experiment using just hot glue to seal cheap corrosion prone chinese electronics (pretty much engulfing it in hot glue as Julien tries at the end of his video), and I was surprised that it failed in just a month or two of wet outdoor weather.
