Nail varnish is NOT a good conformal coating for electronics PCBs!

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  • เผยแพร่เมื่อ 5 พ.ย. 2024

ความคิดเห็น • 17

  • @hullinstruments
    @hullinstruments 4 ปีที่แล้ว +24

    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.

    • @ericfung3308
      @ericfung3308 3 ปีที่แล้ว +1

      this definitely is helpful. Gonna use it for my capstone research haha. thanks!!

    • @hullinstruments
      @hullinstruments 3 ปีที่แล้ว

      @@ericfung3308 Glad to help… If you don’t mind me asking… What is “capstone“? I’m not familiar with the term. Probably makes me seem really stupid but it’s just a term I haven’t heard before.

    • @MayankJairaj
      @MayankJairaj 2 ปีที่แล้ว

      @@hullinstruments it basically means final year/term of academics. These usually will require you to use most of the skills you learn during uni.
      And thankyou for the write-up; believe you me when I say I had a clear nailpaint bottle in my hand and was going to apply it on the bms and step down thingy
      Best case scenario it would have just killed the circuit.
      I'll be getting the epoxy soon, but I had a question, if this is waterproof then how do the industry peeps get the cooling part sorted out?

  • @piteoswaldo
    @piteoswaldo 5 ปีที่แล้ว +21

    I think the problem is dirt under the coating. You should clean the surface before applying any coat.

  • @odfpv591
    @odfpv591 4 ปีที่แล้ว +3

    Thinner coats are better than a mm of polish but in the end silicon conformal coating is king

  • @jorgejimenezrazgriz3951
    @jorgejimenezrazgriz3951 4 ปีที่แล้ว +6

    Maybe you didnt clean the pcb enough before applying the varnish.
    Was the pcb directly exposed to sunlight or rain?

  • @Veksta
    @Veksta 3 ปีที่แล้ว +1

    Maybe because its designed to go on microns thick and you have put it on mm's thick? As conformal coating to seal a pcb where you have cleaned up corrosion or pulled back solder mask for any reason nail varnish works 1000% fine.

  • @Duzzii_
    @Duzzii_ ปีที่แล้ว +1

    Was the clear nail polish acrylic ? Or did u just use glossy nail polish lol

  • @CyberlightFG
    @CyberlightFG 6 ปีที่แล้ว +6

    Looks like a temperature problem.

  • @4dirt2racer0
    @4dirt2racer0 3 ปีที่แล้ว

    idk if u just used junk stuff, but iv actually stopped using nail polish for this because it would stick to well, since it peeled the way it did yet stuck great in other areas makes me wonder if u didnt clean the parts properly, youd b shocked at how much stuff is on a single component

  • @gmanindustries2133
    @gmanindustries2133 2 ปีที่แล้ว +2

    I use it on console when I do liquid metal modifications.I cover the transistor around the gpu.you must understand you need to read the ingredients to the clear Nail polish.look for metal poweder ingredients that is not what you want to us.you need none aluminum powder.since 2016 I been modifying console with thermal grizzly and the nail polish.it works well for years my ps4 pro still runs and I have ps5 I probably will redo the liquid metal.I’ve done my share of switches and Xbox’s.you’ll get it one day.

    • @spideyz64
      @spideyz64 7 หลายเดือนก่อน

      Good to hear it's working for years. I'm going to do this on my laptop and I'm going to use a normal clear nail polish. Even if it get's brittle, we can remove it with a nail polish remover.. I'm not going to be removing it anyway. The heat from the gpu is not gonna affect it right?

  • @wrndlabs
    @wrndlabs 5 ปีที่แล้ว +2

    That unit that was on the antenna, was it exposed to UV from sunlight? Directly or partially from surfaces close to it?

  • @userou-ig1ze
    @userou-ig1ze 4 ปีที่แล้ว +4

    I think if I wanted to bore viewers I would be as repetitive as this guy. It could be summarized in 30s.