Fully waterproofing board [SERIOUS]

[RDs]

I know topics similar to this exist, however the goal of this one is to cover all the possible practices for enclosure and board waterproofing, starting from materials/brands, ending with how well waterproofing technique works, and whether it deteriorates over time, what maintenance is necessary. I will update this post as we get more info and experience from others.

Case:
Rubber gasket method:
As far as I know it’s very weakly water resistant, one puddle won’t do much, but persistent humidity presents risk.

Neoprene sheet method, very commonly used, easy to service parts, has risk of degrading over time. Looking for info on reliable brands/setup:

Fully waterproofing board [SERIOUS]

If the neoprene is “open cell” then it’s going to take in a lot of water, especially if it’s being flexed by a board. Make sure only closed cell neoprene is used for any sealing. I haven’t had any problems with closed cell neoprene but it’s always been compressed 50%-75% or so making it tough for any water to get in even a little. Depending on how flat it’s squeezed it can take a “set” and not bounce back well but I have had good luck with that as long as I use good quality neoprene and don’t…

Neutural silicone metod.
Not the nicest method, but was pretty reliable for 2pc enclosure with base, and lid on top:

During every assembly of the case I have to add new layer of automotive grade silicone, I also used it on top of bolts in order to insure no water gets through those holes. It’s not the nicest method, nor the easiest to make modifications for, but it was really reliable. After 2 dis-assemblies 0 humidity present.

For ESC cooling plate, similar method was applied. In this example I over did it and it degraded cooling capabilities of plate, silicone was only necessary on edges and bolts. Still reliable after 1 year of use, hard to service.
@Pedrodemio approach to same method:

Fully waterproofing board [SERIOUS]

The route I went is enclosure lids held by screws and a generous amount of silicone, every time you open you have to cut it, clean everything and apply again. For wires the only solution in no wires going through the enclosure, only connectors glue really well and fully covered with silicone from the inside Have a lot of pictures here Gathering Storm | Trampa HolyPro | Dual 6355 | 10S5P | VESC 6 | Submersible

Butyl tape method:

@b264

Also, once I discovered butyl tape, my water resist game went up tenfold… That stuff is the be-all and end-all of enclosure water resist game.

Cables, wires, connectors

@b264 approach with epoxi + general tips

@b264

Also, having no holes other than a sealed (from the inside) charge port helps immensely. Epoxy all Amass XT- and MR- connectors male end through the enclosure, and no leaks.
Never run wires or cabling through the enclosure, and do not use cable glands or similar items. Don’t run wires over the edge of the enclosure either.
This is my newest “best way” to make stuff work in any environment, dust, water, brine, whatever.

Magnum Seed | Rayne Demonseed 44 | 78mm Venom Magnum [Serious]

Magnum Seed an LEV build by b264 click to animate [20201024_033729] This build has been in some sort of “done” state for a few months now, but I’ve been tweaking things and I think this may be close to the final form. The first iteration had 63mm motors but that just didn’t work with the 78mm wheels no matter how I arranged it. I’ve got the motor can ground clearance up to 31mm from 8mm in the first iteration, helped greatly by the switch to 50mm motors. So what’s my favorite th…

Battery:
Heatshrink + epoxi on both ends. Reliable, also used it on drones in rapidly changing temperatures without failure.

Motors:
Hall effect PCB’s should have conformal coating applied. Motors eject water out naturally on their own. On the connection point heat shrink should be applied (prefferably with glue inside), to prevent water from creeping up the cables and into the case.
Looking for info on how to protect motor bearings reliably (I had theory of using neutral silicon or water repeling paste on top but haven’t tested.)
Looking for info on waterproofing 3pin XT60 connectors or alternatives.

PCB’s:

Couple of coats of polyurethane conformal coating does the job. This brand has so far lasted for 1 year without cracking. Only available in EU?

@b264 solution to conformal coating using MGchemcals

Fully waterproofing board [SERIOUS]

[image] Some advice regarding conformal coating from @b264 : He primarily uses MG Chemicals conformal coating. You want to get the bottles that come with a brush in the cap for applying. The go to is #419D, the acrylic coating. #419C is thinner, thus better for covering things like ESC mosfets, but unfortunately it is discontinued. He also uses #4223, urethane coating, for bigger things like loop-keys and big wire connections. Although #419D also would work. (Note: #4223F is not the same, th…

@Battery_Mooch Method for dipping main PCB in rubber/silicone compounds. “Almost any tool handle coating or potting compound can be used as long as the board isn’t getting too hot or used in too cold a place. Flexibility needs to be considered too…”

Fully waterproofing board [SERIOUS]

I’m a huge fan of soldering all the wires on, with strain relief, and then dipping the board into any of the rubber- like (tool handle “rubber”) or silicone compounds to create a seal around everything, a couple of millimeters thick or so. Or brushing on the compound. If embedding the board is worrying me, due to anticipated serviceability issues, then IMO I need to use a more reliable setup that won’t make me worry so much about replacing components. If something blows, just replace the board …

Deck:

Wheels, bearings:
Ive heard folks using layer of silicone in front of bearing to avoid water getting in. Not sure if that really works. I instead opt fur buying cheaper 2RS bearings every 200-300km’s. Cleaner solution to this would be nice.

[Blix]

Butyl might be nice for some applications for example bolts.
I have not used it yet but have heard from boat applications around my area and here on the forum.

[frame]

@b264

[RDs]

Ok, to keep this on track. Enclosures methods that Ive seen having reasonable success.

@Pryside 3D printed case, which is fully enclosed and sealed before being attached to the board. Looks bulletproof to me, but hard to service. Similar to method I used on my board.

My 3D Printed BOOSTED BOARD KILLER - YouTube</title @9:72s
This could easly be overcome with oring gasket Ive seen used on larger scale aswell.

Regular case with foam/rubber gasket, I see this being used very often, is it just preventative measure from splash damage or an actually reliable long term solution? Obvious weak point I see are bolt holes and areas between bolts. Once deck flexes small amounts of water can enter and cause havoc.
@taz setup

eboosted enclosures also have rubber gasket available separately is it waterproof or splash proof?

Window weather windowseals:
@WARMAN from other forums

New 6m Foam Draught Excluder Weather Seal Strip Insulation Door Window | eBay

Come in different names, Ive seen better executions of the same setup, biggest problem seems to be connection point between both ends of the seal (as I haven’t seen one single peace seal available, which at that point should be considered gasket).
Positive takeaway from this method is multiple small layers of the seal, Ive seen similar approach used in car windows and gas boiler seals, if one layer fails, there is 2nd and 3rd one.

[PixelatedPolyeurthan]

From my experience, the only water proof solution is first you you make the enclosure as water tight as possible and then you make all the electronics waterproof by either multiple layers of conformal coating or by potting the electronics in silicone and using waterproof connectors… So anything except JST connectors.
This way if minimal water does leak into the enclosure you safe because the electronics are in a dry suit.
If you wrap your battery full of kapton tape and shrink-wrap it it will take ages for the water to penetrate, so having a but if water entering your enclosure is zero issue imo.

[rusins]

What do people do about JST connectors / other exposed ports when waterproofing their ESCs? I’m thinking of just letting them be, hoping that the enclosure waterproofing works well enough for it not to be an issue

@PixelatedPolyeurthan

If you wrap your battery full of kapton tape

Sounds like such a waste to me, and kapton traps in heat as well… I wonder if our batteries even ever produce enough heat where regular tape would get melted, but I guess that’s a topic for the battery builders club.

[RDs]

@PixelatedPolyeurthan

by potting the electronics in silicone and using waterproof connectors… So anything except JST connectors.

I guess conformal coating is the best of both worlds, silicone absorbs heat too well to be used for a serious build.

@rusins

What do people do about JST connectors / other exposed ports when waterproofing their ESCs?

Don’t count this as experience, as I haven’t gotten to that part of the build yet. However one solution I considered was moving connectors outwards of ESC, conformal coat ESC, then waterproofing connection with heat shrink/other means.

[Battery_Mooch]

@RDs

I guess conformal coating is the best of both worlds, silicone absorbs heat too well to be used for a serious build.

Any material will pull heat from an ESC better than air. If a silicone potting compound pulls heat well that makes it a perfect material to use for waterproofing as that means it gets the heat off the localized hot spots on the circuit board and spreads it out. The increased surface area then makes it easier to transfer the heat to the air.

A conformal coating offers a lower thermal resistance than a thick silicone layer but a lower thermal resistance leading to what…air? That doesn’t help with cooling unless there is enough space for convection currents (there isn’t) or the air is moving (it isn’t).

The silicone potting acts as a heat spreader and thermal mass to buffer and spread out the pulses of heat generated during acceleration. It has real advantages and, for this application with such limited opportunities to get rid of any heat, I would easily pick a block of potting compound over a conformal coating for cooling.

There are downsides to potting, like serviceability, but it’s the better option for spreading out heat and eventually shedding it IMO.

[RDs]

You are right about even heat dissipation part, So yes, if done correctly silicone potting is pretty bulletproof. Appart from hard servicability, it’s a good option. Putting this on my bucket list to test in future with heat camera.

Dug up one of many scattered water tightening topics. Will update main post.

The goal of this post is to both, provide newcomers with possible solutions to water tightening their boards, as well as improve current builds. In Latvia Riga, we have really bad cycle ways on many of our main bridges, puddles tend stay for multiple days. It also gets rainy during some seasons, quite stupid to have to pick up bicycle because of some little rain outside during morning hours.

Still looking for more info. Methods that have and haven’t worked in past, products that don’t really work, should be avoided etc. Even if method provides only slight splash resistance is still method worth noting. Also I have seen lot of folks using neoprene, is it truly that watertright? Or does it degrade over time. My personal experience with it has been bad. Over time it takes mushed shape and let’s water past it’s seal.

[rusins]

Some advice regarding conformal coating from @b264 :

He primarily uses MG Chemicals conformal coating. You want to get the bottles that come with a brush in the cap for applying. The go to is #419D, the acrylic coating. #419C is thinner, thus better for covering things like ESC mosfets, but unfortunately it is discontinued.

He also uses #4223, urethane coating, for bigger things like loop-keys and big wire connections. Although #419D also would work. (Note: #4223F is not the same, that is polyurethane)

wire → solder → apply 419D → heatshrink (before it dries) → more 419D

"
419C was perfect from covering up direct FETs like on FOCBOX. Now I use 419D for that but CAREFULLY. Practice first on things in your trash can. You want to get them covered with a single coat. Fully covered, but with the thinnest possible coating. That’s only right on the actual FETs. Everywhere else including between them can be thick. In fact, I make sure to get right up to the edge and on the edge of them. You don’t want water to short out the “gate” pin of the FET which can lock up the motor at speed.
"

MG Chemicals modified silicon and #422B are not as good.

Some of these conformal coatings shine purple in UV light!

Protip: if you have no blacklight, then you can take it outside into direct sunlight and they will all glow purple from the UV in the sunlight alone.

Sorry for posting for you Brian, if there’s anything else you want to mention or clarify, go ahead

[Battery_Mooch]

I’m a huge fan of soldering all the wires on, with strain relief, and then dipping the board into any of the rubber- like (tool handle “rubber”) or silicone compounds to create a seal around everything, a couple of millimeters thick or so. Or brushing on the compound.

If embedding the board is worrying me, due to anticipated serviceability issues, then IMO I need to use a more reliable setup that won’t make me worry so much about replacing components. If something blows, just replace the board and repair later if possible.

Screws are put through all mounting holes first so they can be removed to reveal the holes.

Pressing down a small piece of thin clear plastic onto any LEDs (which are hopefully grouped together) makes it easy to see them.

[Battery_Mooch]

@RDs

Also I have seen lot of folks using neoprene, is it truly that watertright? Or does it degrade over time. My personal experience with it has been bad. Over time it takes mushed shape and let’s water past it’s seal.

If the neoprene is “open cell” then it’s going to take in a lot of water, especially if it’s being flexed by a board. Make sure only closed cell neoprene is used for any sealing.

I haven’t had any problems with closed cell neoprene but it’s always been compressed 50%-75% or so making it tough for any water to get in even a little.

Depending on how flat it’s squeezed it can take a “set” and not bounce back well but I have had good luck with that as long as I use good quality neoprene and don’t squish it flat.

[RDs]

I second the ‘‘soldering wires on’’ part, as I have had project glitch out during demonstration with JST’s and drones falling out of sky because of bad power connection. Hard to service, but proffesional FPV drone pilots have been using this technique for many many years now. (Right now it has come to point where pretty much everything is mounted on a single board and motors directly soldered on mainboard for both reliability and size concerns).
Can you add some pictures as well please? I honestly haven’t seen anyone do this in past to this extent in past.

[Battery_Mooch]

Unfortunately I don’t have any pictures of a soldered/dipped board I can post as they have all been done for clients and no images of the boards can be shared.

They would be pretty boring though. A PCB shape in a black or blue coating with wires hanging off. That’s about it.

[RDs]

Was about to ask if some of this knowledge isn’t company’s secret or something. I guess it looks close to hobbywing/lingy waterproof version style.

[Battery_Mooch]

Nothing high-tech about it. Almost any tool handle coating or potting compound can be used as long as the board isn’t getting too hot or used in too cold a place. Flexibility needs to be considered too.

I just wish there was an affordable clear/translucent compound available in less than 1 gallon buckets!

[PixelatedPolyeurthan]

@rusins

I wonder if our batteries even ever produce enough heat where regular tape would get melted,

serious doubt. i don’t think a battery ever exceeds 40*C given how usage. Unless of course you are pulling battery amps close the max battery amps output.
I prefer a battery that overheats a bit than a battery that shorts and catches fire or starts rusting. Mine is fully wrapped in kapton, never had an issue.

@rusins

What do people do about JST connectors / other exposed ports when waterproofing their ESCs?

i insert the jst and surround it with silicone or hot glue… this way it won’t unplug due to vibration and it increases the waterproofness.
We are not skating underwater lol, but in the case where you ride in a deep puddle or you accidentally ride into the ocean, you have a better chance of saving yourself some trouble.

[Battery_Mooch]

@PixelatedPolyeurthan

i insert he just and surround it with silicone or hot glue… this way it won’t unplug due to vibration and it increases the waterproofness.

For free-hanging or board-mounted connectors I do that too (with hot glue). But then I slide on heat shrink. When the tubing shrinks down it squeezes the hot glue into every nook and cranny and completely fills in the space in the tubing, forming a solid block.

Serviceable? Not a chance. But bombproof and watertight. Fantastic for small PCBs too.

Don’t do this with RTV anyone. It needs exposure to atmospheric moisture to cure.

[PixelatedPolyeurthan]

@Battery_Mooch

But then I slide on heat shrink. When the tubing shrinks down it squeezes the hot glue into every nook and cranny and completely fills in the space in the tubing, forming a solid block.

i do that too!
Also works when you don’t have the right heatshrink shrink ratio or size hehe.

[RDs]

@PixelatedPolyeurthan

serious doubt. i don’t think a battery ever exceeds 40*C given how usage. Unless of course you are pulling battery amps close the max battery amps output.
I prefer a battery that overheats a bit than a battery that shorts and catches fire or starts rusting. Mine is fully wrapped in kapton, never had an issue.

This is an odd ball that I have looked from both perspectives. During Autumn and spring, temperature drops to point where lot of range is lost to cold and some sortof heat insulation on battery would be nice. During hot summers most of the batteries are warm and offer full potential. Question is weather we reach point where, due to heat, lack of cooling would be an issue. (Problem that tesla vehicles face where they run coolant/warming agent through system to maintain perfect temperature in batteries)