This is a copy and paste including several snippets from articles, blog posts, and instruction Tutorials I’ve written over the years. Sorry for the rambling and I hope this helps someone I’m just an electronics geek with a somewhat respectable lab… Who repairs industrial control and automation equipment… Also restore and recalibrate test gear. And big into the laser Hobby. Anyway… Dealing with industrial equipment… I’ve come to learn a lot of things about waterproofing electronic stuff. Since I see hundreds and hundreds of industrial modules every year for repair… I’ve got a decent understanding of how it works. First of all… it’s a good idea to soak the board down really good with 100% alcohol or denatured alcohol. Then scrub the heck out of it with one of those small 1 inch disposable paintbrushes. Then give it another good soaking of alcohol with the board vertically so that it can drip off and take all the contaminants with it. Or better yet use an air compressor to blow off the contaminants and the alcohol. I buy 100% Iso alcohol by the gallon for about $15. And I keep it in a squeeze bottle on my workbench. (One of those squeeze bottles with a 90° angled tip that can be operated with one hand.) I use over a half a gallon a month at least! It really improves my work and I couldn’t live without it. There are a lot of waxy and oily residues that can come on new circuit boards… So degreasing really does help the adhesion and only takes a few squirts of alcohol and a few seconds. And the alcohol evaporates quickly taking any moisture with it. Second.... and probably most important. Try preheating your circuit boards before coating. They can handle a lot of heat But only need to be good and warm. Somewhere around 100 to 150°F would be plenty. This will help the epoxy flow in and around all of the components, And it will also adhere WAY better to the board. Also the longer cure time epoxy the better because it maintains much more flexibility. Some thing like 30 minutes is good, 60 minutes is better. Don’t get me wrong… I go through gallons at five minute epoxy every year and I love the stuff. But the faster the cure time, then the more brittle it will be. And with any vibration, it may can easily begin to pull away from the board or individual pins if it’s extremely rigid. So flexibility is great. Also when it comes to silicone… Be sure you get NEUTRAL cured silicone instead of acid cured. acid curing silicone will smell like vinegar and release acetic acid when curing. Therefore easily damaging copper and tarnishing other metals. Over time it will devour component legs and traces. Also, check out a product called “never wet“ made by rustoleum. You can spray that shit anywhere. On pcb’s, inside of power tools, on bearings, windings of a motor, Inside a brushless fan or motor, on your clothes, on your phone, hell I’ve even opened up GoPro’s and soaked the insides with this stuff when I was going to be in a precarious environment...... literally anywhere. It’s extremely thin (similar to a regular clearcoat…) But it’s hydrophobic and really is like magic.… Check out some of the videos demonstrating it. It really is amazing stuff if applied correctly. Another wonderful off-the-shelf product which is available to regular folks… Is flexseal. Yes I know it’s gotten A laughing with all of the infomercials on TV… but it really is an incredible product and cheap/readily available. Before flexseal, something similar was only available in large quantities by industrial chemical companies. But for $13 you can purchase a can of spray flexseal… or even the thicker caulk like tube. And its dang near bulletproof. If you’re worried about the epoxy pouring off the sides of the board… Then use tape or to make a dam around the board. In other words, stick the tape to the edge of the board with the sticky side facing in towards the circuitboard. Wrap the tape all the way around the board and leave the excess sticking up to make a damn so that you can fill it with epoxy. it leaves a nice perfect perimeter all around the board. Or if you’re wanting to cover the front and back of the board… the even better… Suspended the circuit board off of the table a little. Like the thickness of a coin or something similar. Then you can build a dam all around the board leaving a few millimeters extra on the sides of the board so the epoxy can flow over the top and down in under the board. That way you don’t have a bunch of open edges of epoxy that water can work its way under. But you’ve encapsulated the entire module in one slab of epoxy. If you use the dam building method… simply use some slices of cardboard like a cereal box… And a hot glue gun to build a little perimeter or wall around the board… Using another piece of cardboard or your work bench/table as a base to glue the dam to. The exact size you want. I would probably use a small plastic box a few millimeters bigger than my circuitboard. That way you can pour a little epoxy in the bottom, set your circuit board down into the box on top of the epoxy and spacer, and continue to pour epoxy on top of the board until it pours over the edges and connects with the epoxy around the sides and bottom. A small Tupperware container or any random little plastic box the same size should work fine. Once it’s cured you can pop it out and you’ve got a completely coated/padded module. But instead of a huge brick of epoxy it’s a thin coating with no seams or edges. That covers the entire front back and sides of the board in one smooth gel like coat. Just be sure to watch some acrylic/resin or mold making videos. And be sure to wax your Tupperware container/mold so that it can be removed and doesn’t stick in there. If it’s going to be some thing that’s really abused, then swap out all of your connector screws and crimp terminals with stainless instead of regular steel. And clearcoat any heat sinks or metal that isn’t coded in epoxy. It Makes a huge difference because the smallest amount of corrosion can easily spread under the coatings... wick will begin to delaminate it from the circuitboard. Any type of corrosion or patina whatsoever… Weather The white powdery oxide that forms on aluminum. Or rusting steel.... copper that’s formed a patina… it all Poses a huge hazard to the water resistance of a board. That’s the most common failure point I’ve seen which breaks down the waterproof barrier. For example… The white powder that forms and oxidizes on aluminum. That stuff somehow creeps up under and conformal coating with ease. Like it’s not even there. And most importantly…Keep in mind that NOTHING is waterproof. It may be water resistant but it’s better to leave it a bit exposed so you can dry it out later. The only exception is if you’re willing to completely pot it in a solid brick of epoxy. but then it’s completely unserviceable and it adds a lot of weight/cost. it’s always best to leave certain things open so they can be dried out after a mishap. Whether you leave it out in the sun on a dry hot day, or bake it at low to mid temperatures in an oven. the best methods for drying I found… Is 100% alcohol or denatured alcohol. Soak the entire board, transformer windings, motor windings, soak everything. It will bond to the water and draw it out as it evaporates quickly. Even then… I still put it in the sun While in front of a box fan.....or bake it in the oven. Just to be safe. This is a large cut and paste from several different articles, blog post, and instructional‘s that I’ve written over the years. Sorry for rambling… Hope this helps someone.

A very good review of the various products available. I use nail varnish, no issues as yet.

Great video. Great Scott did a few videos on this a while back, and one other thing he experimented with was true potting compound and epoxies. He also looked at a more extreme condition, water submersion. I think nail polish/lacquer is probably good for 90% of permanent installation of hobby projects (with maybe exception of submerged environments).

Thanks. How do you squeeze the liquid/compound out of the syringe looking tube?

Thanks for this video and information. Very insightful. How do these solutions perform in very cold temperatures? I have a car issue. There seems to be water infiltration and I'm unable to find the source. Evidently, the water causes issues with some of the electronic components in the car. As such, looking for a solution to protect the components from moisture and possibly water splashes. As I live in Canada, it can get really cold (-35 celcius).

Termopasty is also the manufacturer of rosin flux, which is very good to use. It's called Kalafonia. It's solid crystalized flux, it melts with heat or you can dissolve it in IPA to make it liquid.

Hello, thanks for the video, can I use car top clear paint???

Very interesting video, thank you! The way I see it, it's important for any method to allow removing of the material in case of need for repairs/rework. I do small batches (

Great video and information. Thank you.

I use silicone conformal coating specifically made for electronics. It's not that expensive and is quick drying. Even as a hobbyist, you can apply it after circuit board assembly. It is available in both aerosol spray and brush on. I also use potting compound - what you described as epoxy in your video. As my name suggests, I do RV (Recreational Vehicle) electronic projects that can be exposed to the elements, and a waterproof solution is essential. One other advantage of potting compound is you don't need a case. An electronic potting box holding the circuit board filled with potting compound is an economical alternative. Some of my projects use microcontrollers that must be pulled out of the circuit board if a firmware update is needed. To accomplish this, you need to use machined sockets as the standard split finger type can be damaged by potting compound wicking from the bottom. Also, I sometimes have to seal the bottom of components prior to potting, again to keep the epoxy from wicking into the part. DiP switches and such are two examples. I typically do this with the brush on conformal coating, so in some cases, I use both products. Not sure if I would use Nail Polish, lacquer sprays, or other general purpose items when low cost electronic grade solutions are available. You never know what will happen over time. Some products might damage the board or components.

Somewhat expensive, but I use Electrolube silicone conformal coating for small PCBs. A 15ml container with brush is about £7. It works well. just paint it on like nail varnish. You can find it on ebay.

​ @VoltLog Good video! I hope you get back to this topic as there are so many different products. I hope you would cover some of the waterproofing what you can apply even powered on! Product called "Corrosion-X" has multiple solutions that offer protection from water damage (prevent damage) and rustproofing. It seems more suited for pieces in motion to protect em, giving it unique use cases. I seen people apply it to for instant effect. Also here is another circuit board protection Varnish "PRF 202 Plastic Spray".

Many thanks for your information.

Thanks for the tips :)

For the little project I'm working on, I've been thinking of potting. The board doesn't have any mounting holes in it so potting it in a project box is the best way I can think to do it. I can do it with slow setting two part epoxy pretty cheaply.

I'm a simple man - I see useful life hacks, I click Like.

Useful video 👍

i use 2 part expoxy as most of my work is wired (kynar) prototypes. your video is an excellent source of ideas..long may yoy contibue so!!

Paryloc in California specializes in waterproofing electronics for a fraction of the price. We have been doing this for many years.

I just received my new, kronos blade G1 smartwatch, but at times it gits verry hot! Can i spray on or near a fully working watch

Can you try "Tian mu 705" silicone for seal electronic board? Hope is not corrosive

I have a audio player I want to put in my boat. What would you recommend to put on the electronic board?

as a person whose into rc crawlers, i like running through water and mud. which method would you recommond? these things fall too so impact is a factor.

I use the K-5905 and K-5705 silicone from Kafuter for potting consumer electronics and it seems to work great.

I usually use spray conformal coating, which can be purchased fairly cheaply here in the US (not sure about overseas availability). It works fine for me. I suspect it is similar to the PCB spray varnish mentioned in the video.

Great topic and good tips! I had never heard PVB Varnish but I immediately noticed it has its name also in Finnish on the can. And I could find it right away from a local webshop! A year ago I searched for products to use for waterproofing electronics but the only one I found recommended was Loctite 5145. I managed to find only a single shop here that sells and it had to be picked up from the store. Even there it was something I had to ask from the counter and then wait 15 minutes while it was fetched from some back storage. Not to mention it cost 40€. I'm pretty sure it'll dry up before I can use even 10th of it. Money well spent. It's also difficult to apply and the outcome is definately not pretty. :D

I'm trying to waterproof my furnace motherboard, as there is a lot of moisture in the unit. Any suggestions..?

Best one i've ever found was CHT silicone it was easy to apply sticking good enough and if you ever needed to remove it, it was decently easy to just peel off. Problem's its expensive AF

thank you for your clear explanation , my plan is to clean the PCB with wd40 contact cleaner one then I will spray Q20 as protection layer

Thank you for this comparison ;-)

To be honest, I never used any coating on my PCBs - then again, I never needed to place any of them outdoors. Certainly that does mean that the home-etched ones with exposed copper and nothing else don't exactly stay shiny for long, but I've never had any of them fail after any amount of time either. But it's nice to see how many ways there are to skin a cat, and I do have a project in mind that definitely will live outdoors, so... nice line-up!

I tend to use the 15ML Electrolube FSC conformal coating. Just ordered some Kafuter k-705 to see how that compares.

I like Dupont Dynamask dry film for my solder masks. At least, so far. I have some of the Chinese tube gunk but haven't tried to use it yet. I haven't totally perfected my Dynamask film application either, but I'm at around 95% there. With dynamask film as with photoresist I use the sun as my UV exposure source. My exposure time for photoresist is 3 seconds, and 5 seconds for dynamask film. These exposure times are done on a completely clear and sunny day between 11am and 3pm. I am South of Los Angeles California along the coast - so a high UV intensity area. Does that RTV silicone stink? I know the automotive gasket type RTV smells terrible. Thanks for the upload. -Jake :-)

Julian Ilett used uv curable transparent glue to protect his pwmstick thingy. I think it still works all right in english weather.

What abot thermal dissipation?

Oil filled box... The moisture will separate itself and settle down, thus making it easy to remove. Plus it'll provide liquid cooling

I didn't hear any concerns mentioned about coating a PCB so I'd like to add one... heat retention. Coating a board will decrease components' ability to dissipate heat. I would think thicker coatings like silicone and hot glue would have a greater insulating effect. Just something to take into consideration.

What about the edges of the PCB, won't moisture wick in there?

RTV Silicone (pure 100% silicone sealant available at hardware stores) works great. It's used to seal exposed elements like terminal blocks for marine and aircraft applications. It's really good for providing both sealant and strain relief, for example, where wires connect to a pcb. (But it is a bear to remove.)

Saw a vid where a guy used a tiny roller to spread the UV mask, and it came out pretty even. I think if the roller is foam it will go over and around parts to totally seal them. I use the spray because it's easy.

I use plastik spray and it is great for me. Try it.

Very nice

Hi meet you in Constanta personal. I am lookng for some fluid you can put a comlete tool like a camera for example a 360 cam inside that it will work under water too. I sw some years ago in youtube a demonstration for mobiles but do not find t again they put after they did put in the fluid the complete mobile 2 hours inside 1 meter of water. was shown on ces.

how about some testing in a salt water bath for extended lengths of time.

do you know the difference between kafuter 705 and 5905?

I've yet to protect a board from the elements, but I have secured boards in 3D printed boxes before with MS Polymer adhesive (no acetic acid and ridiculously cheap). I'm not sure how water resistant it is however, so if I needed to seal a board in aqueous environments I would probably protect the board with a layer of varnish first then cover it in normal acetic acid silicone sealant for a dirt cheap 100% waterproof solution

dieletric grease?

Hot glue is really bad material for waterproofing your electronics. I have used glue in my aquarium's hood to waterproof some electronic parts which were about 10 cm over water level (very moisture environment because of water evaporation). Hot glue became unstuck from the parts after 6 month. So my suggestion is to use hot glue only when the environment is dry.

My eBike PCB are protected by ACF50 or Boeshield. Good enough for avionics and me. .

hot glue won't protect against moisture for long periods... maybe do a test, how each is coping with moisture with voltage on the circuit

Nail polish can have unexpected capacitance. Be aware!

Awsome

I suggest trying out Plasti-Dip

yet another to your collection "PLASTIK 70"

nail polish is just acrylic. UV smask is epoxy.