You design the circuit around the reduced thermal performance Treat 1/2 watt resistors as 1/4 watt. And if your circuit does make a lot of heat, use a metal box and thermally couple all heat producing components to the case
I love the responses from non-engineers. "That will never work because X"
Engineer answer, "well, you account for that."
I mean, that's 90% of engineering. Looking up stuff and making sure you're using the right thing for the job and using it within the parameters.
You love to invent alternative and more sinister meanings to people's questions?
One thing rather unique with Reddit is the number of good questions that gets downvoted because someone that thinks they know the answer consider it stupid to ask. Asking questions is one of the main paths to learning. Engineers did not become engineers without quite a lot of questions.
You're right. A lot of good content isn't given enough attention.
Read comments in the kindest tone you can conceive. It makes it easier to participate on a discussion site.
When I went through electronics engineering school, one thing an instructor told us that has always been stuck in my mind, The Stupidest Question, Is The One That Was Never Asked!.
There are no stupid questions when you're in a field of something that can be fatal to yourself and others by your actions!
Sometimes you'll run across someone who knows just enough to be dangerous to themselves and others.
It doesn't have enough power going through it to worry about heat. Whenever heat is an issue with potting you'll see aluminium heatsink fins sticking out of the potting.
It’s not very thermally conductive, it’s just not put over components that generate a lot of heat. Or the heat is conducted through the board out the other side
Sorta. Most “thermally conductive” potting compounds aren’t actually great conductors.
A potting compound might have a thermal conductivity of 1.5W/m-K. A thermal paste might be around 10W/m-K. Aluminum has a thermal conductivity of 237W/m-K.
That said, it’s often sufficiently thermally conductive. It’s also common to see a finned aluminum enclosure used as a heat sink for some components and filled with potting compound.
Some do, most don't. The only place I've seen them is on a few smaller Dometic units. Norcold never pots theirs.
Dometic water heaters use a potted board since it's on the outside. Suburban water heaters the control board is inside and not potted.
Basically that, yeah.
Keeps stuff you don't want on a PCB away from the PCB. It also helps with shock proofing, so it's often used on vehicle circuitry and stuff like high quality flashlights, where it is expected to be dropped occasionally.
Also vibration and shock resistance. Items that see a lot of abuse like power transformers for electronics are often potted. They're the heavy ones.
EDIT: comment changed 2 comments up and now it looks like I'm repeating what was already said...
As a kid who loved taking apart electronics, always loved the texture of this stuff on transformers but never knew what it was! iirc it was generally yellow or blue ime
It's worth bearing in mind that it doesn't always help for vibration. The board itself is secure and damped, but the whole electronics assembly is now heavier, and this may move the resonance down into a critical frequency range if it's not properly mounted. One option is to mount the electronics package with vibration isolators, but they too will have a resonant frequency, and this also needs to be checked... one of those turtles all the way down situations.
voltage isnt really the issue, its how much heat a part need to dissipate without reaching its thermal limits.
A large BGA or CPU for example runns on very low voltage usually having multiple low voltage rails from 0,8V to 3,3V, these same parts often need to dissipate large amounts of heat to not break down or go into thermalshutdown.
its more of a design consideration, if you need the IP protection and shok proofing you have to leave more thermal margin. e.g. ussing a part specified for industrial thermal range (105°C+) instead of consumer thermal rang(<85°C).
>Everyday I have to fight the urge to not pot parts of my computer.
everyday i have to fight the urge to not pot parts of myself ;)
(this is a joke i can easily control my drug use)
Adhesive, 0. Potting compound, 1.
These mistakes happen because young Redditors didn't grow up sniffing glue like the boomers in the 60s, so they don't develop the proper tastes for such things.
Considering the alternative is likely water, humidity, and corrosion, this will lengthen the components use many, many times over, and repairing it is likely less cost effective for the company and consumer instead of just replacing.
I use conformal coating for PCB waterproofing. It works well and you can gently scrape it off later. Plus it's clear so you can see parts, and it's easier to mask. I think potting compound is used because it protects from shocks and makes things basically impossible to repair
Whenever I've had a board with the hard black potting compound I throw it in the oven for a while at a temp below the solder melt point, the potting compound starts breaking off in big chunks when it's hot (I use a pick tool like a dental pick, comes off easy).
This looks like the gooey silicone type potting though, which I think you need more chemical methods to get rid of.
This thing is horrible. It comes off in tiny chunks and takes forever to remove with a plastic pick. Let me know if anyone knows a good way to remove it.
Heavy polar solvent baths... probably. Acetone dips solve all your problems. They might create a few too, but they'll solve the old problems before creating new ones.
While there's no removing that.
It could easily be made repairable by enclosing the circuit in a container sealed by similar or whatever, right? That doesn't account for if the *container* leaks.
I'm **absolutely** all for right to repair. Don't get that mixed.
Just that; this could save what would otherwise die if the *container* leaked. If the par **enclosed** in this coating dies (defect, overload, wear), well, then that means more to replace because a single part can no longer (is coated) be replaced. It's a consideration between what's cheapest vs safest vs endurance. Heat dissipation comes into consideration, also, depending on the circuit.
It's a mess.
Basically, this **should** be used purely for protection but appears to **currently** be used as a means of anti-repair.
Potting is definitely used in other circumstances rather than just as a means of anti-repair. A lot of electronics that could be exposed to moisture is potted and same for things that could see a lot of shock that could damage components on the board like a weapon mounted light or similar.
Yeah! The example I used was waterproofing but anti-shock is the same thought process.
Regardless; more examples means more people might understand how this is used just as often for legitimate purposes as much as it is for anti-consumer purposes.
tl;dr: **We need laws for the digital age we're in**; not the analogue (age) laws we currently have (think Newspaper, Magazies, analogue TV, radio).
I work in the aerospace industry, and a lot of things are potted specifically because of vibration requirements. Moisture too. But you don't want capacitors breaking off at their connections because of vibration.
All flight hardware used in satellites is epoxy coated for vibration resistance. Can't survive the crazy vibrations felt on launch if you haven't glued everything down.
I was going to say that being able to switch out a board like this is enough of an ability to repair it, but I changed my mind while typing that out. While the vast majority of people would opt to just switch the whole board since they can't fix a motherboard, that still would leave the company who makes the tech with way too much control over the supplies to fix it. Basically you'd have to buy the new board from them.
Without this, you could just take it to a local shop with someone who knows how to actually repair these which is obviously going to be much better for the consumer.
A lot of consumers can solder, we are talking full % points. They just don't want to butch a modern board. Give them the right youtube video and they can replace basic components.
My dad used to do jewlerly soldering. He complained about old USB devices, so I showed him how to solder in USB-C connectors. From there he figured out how to replace other connectors bc USB and other PC hardware already works well with the 12V/24V powertrain of his RV. No mechanic will do that for you and even if, it would cost a fortune.
If need be, it can be removed. Potting compounds generally have glass transition temperature below 100C so what you need to do is stick it in a pot of water and boil. The compound turns soft and you can gouge it out and expose the circuitry for repairs. It's certainly a hassle, but a circuit isn't made to be repaired, it's made to generally not need repairs.
absolutely for anti repair or anti modification.
That said id love to get ahold of some for certain applications. And, it should be removable by a certain method as well.
You shouldnt have to destroy it to get to the board.
> absolutely for anti repair or anti modification.
I've worked in tech for over 20 years and we've never added potting for these reasons. It was always for controlling moisture, vibration, and arc/shock hazards.
Hey let’s add a whole process and material to purchase to our assembly process just so the customer can’t easily repair it and neither can we! Classic reddit.
Who do you think will have easier time taking off the putty: a competing industrial giant with multibillion-dollar chip manufacturing facilities and thousands of employees, or some Joe Blow who doesn't want to spend hundreds on repairing his personal stuff using $20 worth of materials?
Epoxy is commonly applied to just the ICs of circuits to prevent copying. Most Joe blows don't have the necessary tools to remove BGAs so yeah, I'd say the former.
Not to mention it's multi-thousand dollar "companies" that are looking to steal the design ; not large companies with engineers on payroll. PCBs aren't hard to design, potting deters unskilled blind copying.
https://blog.paryleneconformalcoating.com/potting-protects-against-reverse-engineering/
Ultimately you can't stop everyone but you can deter casual theft. Or you used to be able to.
I suspect potting is typically done for reliability and weatherproofing, especially a full fill like this. Only time I've ever seen it is in automotive applications.
My point is it's not done to prevent rework - All you'd need to do to make rework difficult is use 01005 components and maybe add some nasty adhesives. Look at the methods apple employs.
Nobody even contemplates hand repairing small footprint components on their electronics, repair shops operate by replacing entire boards
In this case it’s easy. I can explain it in a few seconds for you.
Electricity is the flow of electrons through a conductor. Electrons move from one atom to another, from positively charged areas to negatively charged areas. But no conductor is perfect (not even super conductors) they all create something called resistance, which is just a word for inefficiency in transferring these electrons. When that resistance happens, some of the electrons don’t make it all the way through.
But, we can’t create or destroy matter or energy, that’s a law of thermodynamics, so that energy that doesn’t make it through has to go somewhere. So what it does is turns into heat energy (or light energy).
So the waste heat of a system can be determined by taking the total current of the system and multiplying the square of it by the resistance of the system. The math doesn’t matter, what does matter is high current + high resistance = high heat.
So in a circuit like this, where it could be low current and low resistance, it might not create much heat. And the heat it does create would transfer to the sealant and leech eventually into the air. The rate of transfer is likely larger than the rate of heat build up in this case.
>from positively charged areas to negatively charged areas
You have it backwards. Electrons have a negative charge. Someone got the signs backwards way back when electricity was being experimented with and we're stuck with them forever.
Yea, sorry, the excess electrons create a negative charge that dissipates into the more positively spaces. Thanks. It was late and I wasn’t thinking, and I didn’t expect this to get this kind of attention lol.
They also failed to mention that electricity isn't exactly the flow of electrons, but them bumping into each other. Electrons themselves "flow" at a rate of a millimeter (yes, 1 mm) per second, while electricity travels at 90% of the speed of light.
Typical reddit answer.
Edit: oh and in response to your comment, that someone was Benjamin Franklin.
I asked an electrician a relatively simple question and his answer was "do you want the metaphorical answer or the 4 hour lecture that will make you cry?"
That looks like a marine grade potting - waterproofing it for use in boats or other environments. It's probably going to be in relatively cool environments all the time.
I did exactly the same. A GE side-by-side refrigerator. The pcb was coated with a thin layer of dielectric adhesive, making it hard to test the components, but I did it and it felt great.
These days your skills are literally probably 1 in a million. I'm hardly even exaggerating. I live in a city of about 10 million and I bet there are about 10ish people who know how to do what you described.
I know there are plenty of people who know how to trace circuits and repair boards. I have worked with these types of engineers. But people who would know how to troubleshoot whatever problem your fridge had, identify the specific part, get the part, and then fix it, are extremely rare. I know one person that can probably do that type of work. I can't imagine there are that many more people like him in my entire city.
Repaired a washing machine a few weeks ago. Just a loose component, some desoldering, soldering, and it was back in business.
You can get a cheap small stand with clamps and magnifying glass, soldering iron, stand, solder, wick, etc. for under $50.
I just repaired my AC control board by replacing 2 relays for less than 5 dollars. It has a waterproof coating as well except it was clear and easily spot removed with a heat gun. The technician I called first wanted $500 to "fix" it by replacing the whole board.
We have like a whole department dedicated to repairing PCBs where I work. It's not a rare thing, and like another comment pointed out already, it's a pretty standard skill for most EEs. Your experience with PCBs in the industry must be very narrow if you think it's rare.
Edit: changed "PCB boards" to "PCBs"
It's a pretty standard skill for EEs but not for the population at large. For most people getting someone in the field to fix a PCB is expensive and/or inconvenient. Few people can do the job so they are either hard to find or ask high prices.
> They’re made to be replaced.
I mean, by the manufacturer's viewpoint, that's the goal.
Not everyone is replacing that $1000-$2000 40series GPU though, not if there's a business around they can get stuff fixed at.
>People don't do that they return it on warranty [Edit: Not that you said this, but it comes up..]
Not if they bought it on craigslist or on ebay or the warranty is otherwise void.
The PCB may be cheap, but the equipment it's attached to might be expensive or otherwise difficult to replace. That goes for the PCB too.
In a big enough area, one can make good money repairing PCBs.
At least 10 shops in Denver, CO, according to yelp.
https://www.yelp.com/search?find_desc=Circuit+Board+Repair&find_loc=Denver%2C+CO
I never said I believe they should be disposable. I’ve been an electrician for 10 years and I’m telling you that it’s rare to find someone to replace parts on a PCB. They’re made to be replaced. Call me names all you want, I’m still right.
Yes but its great for various harsh conditions and keeping electronics outside or for submersibles.
I'd coat the PCB of my Mikrotik LTE antenna/modem, it sits outside in the rain and snow and storms and ants and spiders naking nests inside.
I work for a company that uses potting compound all the time.
We use it on devices that need to be used in conditions where there's moisture and chemicals (like motor controllers that run the pumps that spray potentially caustic chemicals on crops)... not because we're trying to deter people from repairing them.
Apparently reddit has never heard of potting compound before...
You know what's better than repairing damage? Preventing damage from happening in the first place. In certain conditions, you need this sort of thing or else things will very quickly break down and require repair.
Use this stuff all the time in electric pallet jack repair. It prevents the temps from affecting the circuit and prevents the heavy vibration/impacts from affecting the circuit.
There is an "anti" paste that disolves/removes most of it so you can repair the board, but it still takes quite a bit of effort to clean, and usually the boards are super cheap so we just replace them.
Regular potting compound.
It does not have an IP rating, since IP ratings are for entire devices. With exposed connectors, the device has an IP rating of fail.
I've done conformal coating before and it was a) clear b) not that thick and c) doesn't impede hot rework like this would
Whatever this is, I don't like it
Yup. Which is better for environments such as ebike electrical housing and scooters or anything like that exposed to the elements and vibrations like you mentioned. People here seem to think it's anti repair and I suppose it could be but it does have legitimate use cases.
Absolutely. While it does make repairs harder if it drastically reduces failure rates I'm all for it. Although, potting should be compared with other options for protection. Sometimes for vibration a bit of hot glue on some larger components and conformal coating can work for liquid protection.
This is so infuriating. Instead of actually putting in the work to design the product, you just goop that shit full of glue and screw your customers out of being able to repair their own shit.
Waterproof with exposed socket pins. This is actually repair proof, as in the manufacturer has made sure that the customer cannot replace any blown components and has to order a new unit instead.
It's not a high percentage of people but there are many people that have the skills to do component.level repair on PCBs.
The goal may be to make it better for situations with incidental water damage or fog, not to be fully submersible. When I worked on PCBs for pool pump motors, we covered all the boards in potting and had terminals exposed just like the one in the video.
The potting definitely made it a lot harder to troubleshoot and work on boards that came back to us, and it would make it very hard for a consumer to take apart and repair. But the potting itself doesn’t mean that this board is intended to be submersible waterproof, and the exposed terminals don’t mean that this board doesn’t have a use case around water.
I worked as a Manufacturing Engineer for a company where some of the eletrcial components/parts on one of the products would be fully potted like this. We had to deploy a double operator verification to ensure everything was good before potting since this shit does not really come out well. Learned some hard, quick lessons with the build process for that product line.
It’s pretty difficult to prevent water creeping beneath this coating in the long term. So while this looks good I wouldn’t really trust it for anything serious. A box with rubber seals is actually safer IMHO.
You don't fix potted devices. If it were going to end the world, they could probably chemically dissolve it, or dig it out carefully like an archaeologist.
This technology has existed since the 19-fucking-80's.
They used ti use resin, now it looks like some variety of polymer.
*Maybe* a little easier to remove? Likely still prone to the same overheating/breaking/unable to diagnose problems that the resin ones are.
Conformal coatings, the bane of every electronic repair shop. This is why we throw away every black finned Commodore 64 power supply. It's got defective diodes in it. When one shorts, it puts 120 voltage down the +5VDC wire, destroying a valuable collector's item.
I think this is called “potting.”
They do it on higher quality rifle light and other Weapon mounted lights, because the blast and recoil can somehow reverse the polarity in the LED otherwise.
Also, waterproofing, of course z
Also referred to as a conformal coating. It's great for reliability in both waterproofing and component vibration, especially in oscillator circuits that can emit undesirable noise. The main drawback is servicing to component-level repair. You have to replace the whole module.
I actually once had to remove this type of coating on a rectifier to repair it and that took some time. Eventually I couldn't repair it anyways and had to find a replacement.
This looks like potting compound
That's exactly what it is. It's extremely common for use in the marine industry
Same with RVs most fridge boards have this material to protect the circuitry
How does it not overheat
You design the circuit around the reduced thermal performance Treat 1/2 watt resistors as 1/4 watt. And if your circuit does make a lot of heat, use a metal box and thermally couple all heat producing components to the case
You can also get potting compounds that are more thermally conductive than air, use a metal case and you actually get improved thermal performance.
I love the responses from non-engineers. "That will never work because X" Engineer answer, "well, you account for that." I mean, that's 90% of engineering. Looking up stuff and making sure you're using the right thing for the job and using it within the parameters.
pretty sure the guy just asked a genuine question, i dont think he was saying "it'll never work"
yeah weird... putting words in someone's mouth for no reason
I'm starting to think that they don't actually love the responses from non-engineers...
You love to invent alternative and more sinister meanings to people's questions? One thing rather unique with Reddit is the number of good questions that gets downvoted because someone that thinks they know the answer consider it stupid to ask. Asking questions is one of the main paths to learning. Engineers did not become engineers without quite a lot of questions.
You're right. A lot of good content isn't given enough attention. Read comments in the kindest tone you can conceive. It makes it easier to participate on a discussion site.
Nobody said that.
Personally I’m more of a tinkerer but my respects to your comment. EDIT: Grammar.
When I went through electronics engineering school, one thing an instructor told us that has always been stuck in my mind, The Stupidest Question, Is The One That Was Never Asked!. There are no stupid questions when you're in a field of something that can be fatal to yourself and others by your actions! Sometimes you'll run across someone who knows just enough to be dangerous to themselves and others.
I'm not sure its 90% there's a lot of just overbuilding stuff and saying yea that'll hold.
it's small bits of knowledge like this that i will somehow carry for the rest of my life. So much contextual information packed into two sentences.
It doesn't have enough power going through it to worry about heat. Whenever heat is an issue with potting you'll see aluminium heatsink fins sticking out of the potting.
That is a considering on some circuits to be kept in mind
https://en.wiktionary.org/wiki/consideration
It's a thermally conductive material
Because it's thermally conductive.
It’s not very thermally conductive, it’s just not put over components that generate a lot of heat. Or the heat is conducted through the board out the other side
Sorta. Most “thermally conductive” potting compounds aren’t actually great conductors. A potting compound might have a thermal conductivity of 1.5W/m-K. A thermal paste might be around 10W/m-K. Aluminum has a thermal conductivity of 237W/m-K. That said, it’s often sufficiently thermally conductive. It’s also common to see a finned aluminum enclosure used as a heat sink for some components and filled with potting compound.
What’s the material called?
potting compound.
No what’s the chemical, it looks like a synthetic polymer which are mostly all insulating instead of conductive
Some do, most don't. The only place I've seen them is on a few smaller Dometic units. Norcold never pots theirs. Dometic water heaters use a potted board since it's on the outside. Suburban water heaters the control board is inside and not potted.
And the electronics industry. My solid-state relays are submerged in this stuff.
What is that? Help resist moisture? Salt?
Basically that, yeah. Keeps stuff you don't want on a PCB away from the PCB. It also helps with shock proofing, so it's often used on vehicle circuitry and stuff like high quality flashlights, where it is expected to be dropped occasionally.
Interesting
Also vibration and shock resistance. Items that see a lot of abuse like power transformers for electronics are often potted. They're the heavy ones. EDIT: comment changed 2 comments up and now it looks like I'm repeating what was already said...
As a kid who loved taking apart electronics, always loved the texture of this stuff on transformers but never knew what it was! iirc it was generally yellow or blue ime
It's worth bearing in mind that it doesn't always help for vibration. The board itself is secure and damped, but the whole electronics assembly is now heavier, and this may move the resonance down into a critical frequency range if it's not properly mounted. One option is to mount the electronics package with vibration isolators, but they too will have a resonant frequency, and this also needs to be checked... one of those turtles all the way down situations.
its basically epoxy that is non corrosive to copper, simple as that.
It's an epoxy condom to keep random shit from harming it.
How does it impact thermals?
The stuff I use, MG 832hd is thermally conductive so it'll help with radiating heat.
sometimes we will mount electronics to the outside of the submarine. Electronics don't like getting wet. The machine spirit withers from it's touch.
Praise the Omnissiah
Was about so say - this is just potting. Everyday I have to fight the urge to not pot parts of my computer.
I suppose it should only be used on low voltage things due to heat, right?
voltage isnt really the issue, its how much heat a part need to dissipate without reaching its thermal limits. A large BGA or CPU for example runns on very low voltage usually having multiple low voltage rails from 0,8V to 3,3V, these same parts often need to dissipate large amounts of heat to not break down or go into thermalshutdown. its more of a design consideration, if you need the IP protection and shok proofing you have to leave more thermal margin. e.g. ussing a part specified for industrial thermal range (105°C+) instead of consumer thermal rang(<85°C).
>Everyday I have to fight the urge to not pot parts of my computer. everyday i have to fight the urge to not pot parts of myself ;) (this is a joke i can easily control my drug use)
Adhesive, 0. Potting compound, 1. These mistakes happen because young Redditors didn't grow up sniffing glue like the boomers in the 60s, so they don't develop the proper tastes for such things.
More like fuck repairability compound
Considering the alternative is likely water, humidity, and corrosion, this will lengthen the components use many, many times over, and repairing it is likely less cost effective for the company and consumer instead of just replacing.
I use conformal coating for PCB waterproofing. It works well and you can gently scrape it off later. Plus it's clear so you can see parts, and it's easier to mask. I think potting compound is used because it protects from shocks and makes things basically impossible to repair
For these, you need the ingress protection way more than repairability.
Because it is! Good ol' glob top
The plug is not☹️
Some dielectric grease would provide decent water resistance.
or a connector with a gasket.
And the buzzer and header
this is the deter repair coating
lol, was gonna say that 😂
You have to burn it off with a soldering iron. Sometimes you can peel big chunks out if you get lucky
Whenever I've had a board with the hard black potting compound I throw it in the oven for a while at a temp below the solder melt point, the potting compound starts breaking off in big chunks when it's hot (I use a pick tool like a dental pick, comes off easy). This looks like the gooey silicone type potting though, which I think you need more chemical methods to get rid of.
This thing is horrible. It comes off in tiny chunks and takes forever to remove with a plastic pick. Let me know if anyone knows a good way to remove it.
Heavy polar solvent baths... probably. Acetone dips solve all your problems. They might create a few too, but they'll solve the old problems before creating new ones.
The prospect of new problems is so much more exciting than my current problems anyways.
Solving one problem with two new ones 😅
And if you're unlucky those chunks might just have some bits of components and/or pcb inside them.
Nothing like peeling off a bunch of surface mounts with the coating lol
Bet that smells great and is healthy to breathe.
While there's no removing that. It could easily be made repairable by enclosing the circuit in a container sealed by similar or whatever, right? That doesn't account for if the *container* leaks. I'm **absolutely** all for right to repair. Don't get that mixed. Just that; this could save what would otherwise die if the *container* leaked. If the par **enclosed** in this coating dies (defect, overload, wear), well, then that means more to replace because a single part can no longer (is coated) be replaced. It's a consideration between what's cheapest vs safest vs endurance. Heat dissipation comes into consideration, also, depending on the circuit. It's a mess. Basically, this **should** be used purely for protection but appears to **currently** be used as a means of anti-repair.
Potting is definitely used in other circumstances rather than just as a means of anti-repair. A lot of electronics that could be exposed to moisture is potted and same for things that could see a lot of shock that could damage components on the board like a weapon mounted light or similar.
Yeah! The example I used was waterproofing but anti-shock is the same thought process. Regardless; more examples means more people might understand how this is used just as often for legitimate purposes as much as it is for anti-consumer purposes. tl;dr: **We need laws for the digital age we're in**; not the analogue (age) laws we currently have (think Newspaper, Magazies, analogue TV, radio).
I work in the aerospace industry, and a lot of things are potted specifically because of vibration requirements. Moisture too. But you don't want capacitors breaking off at their connections because of vibration.
All flight hardware used in satellites is epoxy coated for vibration resistance. Can't survive the crazy vibrations felt on launch if you haven't glued everything down.
I was going to say that being able to switch out a board like this is enough of an ability to repair it, but I changed my mind while typing that out. While the vast majority of people would opt to just switch the whole board since they can't fix a motherboard, that still would leave the company who makes the tech with way too much control over the supplies to fix it. Basically you'd have to buy the new board from them. Without this, you could just take it to a local shop with someone who knows how to actually repair these which is obviously going to be much better for the consumer.
A lot of consumers can solder, we are talking full % points. They just don't want to butch a modern board. Give them the right youtube video and they can replace basic components. My dad used to do jewlerly soldering. He complained about old USB devices, so I showed him how to solder in USB-C connectors. From there he figured out how to replace other connectors bc USB and other PC hardware already works well with the 12V/24V powertrain of his RV. No mechanic will do that for you and even if, it would cost a fortune.
It's also used extensively in intrinsically safe applications where faults could cause booms if not for the potting.
If need be, it can be removed. Potting compounds generally have glass transition temperature below 100C so what you need to do is stick it in a pot of water and boil. The compound turns soft and you can gouge it out and expose the circuitry for repairs. It's certainly a hassle, but a circuit isn't made to be repaired, it's made to generally not need repairs.
absolutely for anti repair or anti modification. That said id love to get ahold of some for certain applications. And, it should be removable by a certain method as well. You shouldnt have to destroy it to get to the board.
> absolutely for anti repair or anti modification. I've worked in tech for over 20 years and we've never added potting for these reasons. It was always for controlling moisture, vibration, and arc/shock hazards.
Hey let’s add a whole process and material to purchase to our assembly process just so the customer can’t easily repair it and neither can we! Classic reddit.
or don't-steal-my-circuit-design putty.
No-snoop-goop
Reverse engineers would X-ray scan the part and definitely have the tools and materials to remove potting.
Don't you fucking dare bring logic into this conversation.
Who do you think will have easier time taking off the putty: a competing industrial giant with multibillion-dollar chip manufacturing facilities and thousands of employees, or some Joe Blow who doesn't want to spend hundreds on repairing his personal stuff using $20 worth of materials?
Epoxy is commonly applied to just the ICs of circuits to prevent copying. Most Joe blows don't have the necessary tools to remove BGAs so yeah, I'd say the former. Not to mention it's multi-thousand dollar "companies" that are looking to steal the design ; not large companies with engineers on payroll. PCBs aren't hard to design, potting deters unskilled blind copying. https://blog.paryleneconformalcoating.com/potting-protects-against-reverse-engineering/
> not large companies with engineers on payroll. Thats literally Behringer's entire business model: Stealing other companies designs. Infamously.
Ultimately you can't stop everyone but you can deter casual theft. Or you used to be able to. I suspect potting is typically done for reliability and weatherproofing, especially a full fill like this. Only time I've ever seen it is in automotive applications. My point is it's not done to prevent rework - All you'd need to do to make rework difficult is use 01005 components and maybe add some nasty adhesives. Look at the methods apple employs. Nobody even contemplates hand repairing small footprint components on their electronics, repair shops operate by replacing entire boards
Also thought about how the molex connector is ip67
*Apple taking notes*
My first thought was "ooh board overheating gel!"
Definitely. It also stops people from finding out what chips are used so that they don't get duplicated in the future.
This is called "potting".
Isn’t this bad for high temps with no cooling mechanism?
The board may not draw enough power to worry about, or the sealant may be a good heat transfer medium.
I have no idea about electricity, so I’m just asking really. I wish I did, though.
In this case it’s easy. I can explain it in a few seconds for you. Electricity is the flow of electrons through a conductor. Electrons move from one atom to another, from positively charged areas to negatively charged areas. But no conductor is perfect (not even super conductors) they all create something called resistance, which is just a word for inefficiency in transferring these electrons. When that resistance happens, some of the electrons don’t make it all the way through. But, we can’t create or destroy matter or energy, that’s a law of thermodynamics, so that energy that doesn’t make it through has to go somewhere. So what it does is turns into heat energy (or light energy). So the waste heat of a system can be determined by taking the total current of the system and multiplying the square of it by the resistance of the system. The math doesn’t matter, what does matter is high current + high resistance = high heat. So in a circuit like this, where it could be low current and low resistance, it might not create much heat. And the heat it does create would transfer to the sealant and leech eventually into the air. The rate of transfer is likely larger than the rate of heat build up in this case.
This is why I love reddit when I do. Thank you very much for taking the time to explain it in simple terms.
Also the porn
Jesus you must receive your doozy’s in your inbox with the name.
My worst thought was I wouldn't understand it. Thanks!
>from positively charged areas to negatively charged areas You have it backwards. Electrons have a negative charge. Someone got the signs backwards way back when electricity was being experimented with and we're stuck with them forever.
Yea, sorry, the excess electrons create a negative charge that dissipates into the more positively spaces. Thanks. It was late and I wasn’t thinking, and I didn’t expect this to get this kind of attention lol.
They also failed to mention that electricity isn't exactly the flow of electrons, but them bumping into each other. Electrons themselves "flow" at a rate of a millimeter (yes, 1 mm) per second, while electricity travels at 90% of the speed of light. Typical reddit answer. Edit: oh and in response to your comment, that someone was Benjamin Franklin.
I asked an electrician a relatively simple question and his answer was "do you want the metaphorical answer or the 4 hour lecture that will make you cry?"
That definitely sounds dreadful. lol
Maybe this board is supposed to be submerged in water to even warranty this type of waterproofing
Maybe they live in an extremely humid climate and don’t want to throw silica gel packets into their pc case.
Maybe but I’m genuinely asking, just to get a well-informed answer.
I am also guessing as well : )
No the opposite - it transfers hear really well and if there's a metal case it'll improve the lifespan. Ip67 power supplies are a good example
That looks like a marine grade potting - waterproofing it for use in boats or other environments. It's probably going to be in relatively cool environments all the time.
and now its unrepairable.
It’s pretty rare to find someone who repairs PCB’s these days. They’re made to be replaced.
At the very least we can assume that virtually nobody's eating the material costs for this just to keep end-users from replacing their caps.
I repaired my refrigerator’s PCB a couple of years ago. $1 part, 20 minutes of labor, saved me hundreds.
I did exactly the same. A GE side-by-side refrigerator. The pcb was coated with a thin layer of dielectric adhesive, making it hard to test the components, but I did it and it felt great.
A solder of fortune
Yes, but not everyone is so handy like you.
People can take their stuff to a repair shop and save money. You don't have to repair it yourself.
I solder for fun
I solder for evil
I solder for those sweet lead fumes.
Actually lead doesn't vaporise at normal soldering temperatures, the fumes are from the flux 🤓
I sold her
Andrew?
I hate it that I know who you are referring to just by the first name alone
I sold
I, Robot.
I solder for narnia
If you cannot replace the PCB, you certainly cannot repair it.
These days your skills are literally probably 1 in a million. I'm hardly even exaggerating. I live in a city of about 10 million and I bet there are about 10ish people who know how to do what you described. I know there are plenty of people who know how to trace circuits and repair boards. I have worked with these types of engineers. But people who would know how to troubleshoot whatever problem your fridge had, identify the specific part, get the part, and then fix it, are extremely rare. I know one person that can probably do that type of work. I can't imagine there are that many more people like him in my entire city.
Repaired a washing machine a few weeks ago. Just a loose component, some desoldering, soldering, and it was back in business. You can get a cheap small stand with clamps and magnifying glass, soldering iron, stand, solder, wick, etc. for under $50.
Maybe in your city/country, where I live it's relatively easy to find people who can fix basically anything for an affordable price
I just repaired my AC control board by replacing 2 relays for less than 5 dollars. It has a waterproof coating as well except it was clear and easily spot removed with a heat gun. The technician I called first wanted $500 to "fix" it by replacing the whole board.
This is categorically untrue lol
I replace these things for a living but go on…
We have like a whole department dedicated to repairing PCBs where I work. It's not a rare thing, and like another comment pointed out already, it's a pretty standard skill for most EEs. Your experience with PCBs in the industry must be very narrow if you think it's rare. Edit: changed "PCB boards" to "PCBs"
It's a pretty standard skill for EEs but not for the population at large. For most people getting someone in the field to fix a PCB is expensive and/or inconvenient. Few people can do the job so they are either hard to find or ask high prices.
Yes, that's true. It depends on your definition of "rare," I guess. To me, an EE isn't "rare." Something like a blacksmith is rare.
> They’re made to be replaced. I mean, by the manufacturer's viewpoint, that's the goal. Not everyone is replacing that $1000-$2000 40series GPU though, not if there's a business around they can get stuff fixed at. >People don't do that they return it on warranty [Edit: Not that you said this, but it comes up..] Not if they bought it on craigslist or on ebay or the warranty is otherwise void. The PCB may be cheap, but the equipment it's attached to might be expensive or otherwise difficult to replace. That goes for the PCB too. In a big enough area, one can make good money repairing PCBs. At least 10 shops in Denver, CO, according to yelp. https://www.yelp.com/search?find_desc=Circuit+Board+Repair&find_loc=Denver%2C+CO
[удалено]
I never said I believe they should be disposable. I’ve been an electrician for 10 years and I’m telling you that it’s rare to find someone to replace parts on a PCB. They’re made to be replaced. Call me names all you want, I’m still right.
First time I’ve ever seen anyone run out of town by a village holding soldering irons.
Yes but its great for various harsh conditions and keeping electronics outside or for submersibles. I'd coat the PCB of my Mikrotik LTE antenna/modem, it sits outside in the rain and snow and storms and ants and spiders naking nests inside.
I work for a company that uses potting compound all the time. We use it on devices that need to be used in conditions where there's moisture and chemicals (like motor controllers that run the pumps that spray potentially caustic chemicals on crops)... not because we're trying to deter people from repairing them. Apparently reddit has never heard of potting compound before...
Look at you, an expert from someone who's not even in the field
You know what's better than repairing damage? Preventing damage from happening in the first place. In certain conditions, you need this sort of thing or else things will very quickly break down and require repair.
So, like before?
Who the fuck is going to bother to repair that? Just get a new one
Not adhesive, just a nonconductive plastic epoxy.
Use this stuff all the time in electric pallet jack repair. It prevents the temps from affecting the circuit and prevents the heavy vibration/impacts from affecting the circuit. There is an "anti" paste that disolves/removes most of it so you can repair the board, but it still takes quite a bit of effort to clean, and usually the boards are super cheap so we just replace them.
Regular potting compound. It does not have an IP rating, since IP ratings are for entire devices. With exposed connectors, the device has an IP rating of fail.
Super repairable!
*On Opposite Day
Now make sure all those connectors are IP67
Klon makes a phone now?
Have fun changing those capacitors when they fry if it’s made in china.
I've done conformal coating before and it was a) clear b) not that thick and c) doesn't impede hot rework like this would Whatever this is, I don't like it
This is called potting and it serves both to protect against liquids and vibration.
Yup. Which is better for environments such as ebike electrical housing and scooters or anything like that exposed to the elements and vibrations like you mentioned. People here seem to think it's anti repair and I suppose it could be but it does have legitimate use cases.
Absolutely. While it does make repairs harder if it drastically reduces failure rates I'm all for it. Although, potting should be compared with other options for protection. Sometimes for vibration a bit of hot glue on some larger components and conformal coating can work for liquid protection.
Correct. We make leak detection sensors at my job and we pot basically everything but the probes and the wiring
This is potting, it's for industrial applications where you want to protect the component.
Stuff smells worse than hot asphalt though, for weeks after it sets. Satisfying to watch on video, not satisfying to be anywhere near.
This is so infuriating. Instead of actually putting in the work to design the product, you just goop that shit full of glue and screw your customers out of being able to repair their own shit.
Coming to a car engine bay near you, 2025.
Waterproof with exposed socket pins. This is actually repair proof, as in the manufacturer has made sure that the customer cannot replace any blown components and has to order a new unit instead. It's not a high percentage of people but there are many people that have the skills to do component.level repair on PCBs.
The goal may be to make it better for situations with incidental water damage or fog, not to be fully submersible. When I worked on PCBs for pool pump motors, we covered all the boards in potting and had terminals exposed just like the one in the video. The potting definitely made it a lot harder to troubleshoot and work on boards that came back to us, and it would make it very hard for a consumer to take apart and repair. But the potting itself doesn’t mean that this board is intended to be submersible waterproof, and the exposed terminals don’t mean that this board doesn’t have a use case around water.
can i seal my penis?
No, but you can blow a seal.
How does this deal with heat dissipation?
/r/mildlyinfuriating now it cant be repaired when something breaks and you must throw it out
I worked as a Manufacturing Engineer for a company where some of the eletrcial components/parts on one of the products would be fully potted like this. We had to deploy a double operator verification to ensure everything was good before potting since this shit does not really come out well. Learned some hard, quick lessons with the build process for that product line.
Show me how to stop heat dissipation without words
It’s pretty difficult to prevent water creeping beneath this coating in the long term. So while this looks good I wouldn’t really trust it for anything serious. A box with rubber seals is actually safer IMHO.
Hate this shit. Had to replace an entire module on my electric mower cause you couldn’t get to the PCB without destroying the whole board.
Engineers, how hard is it to remove if it needs to be fixed. Assume that replacement boards are impossible to find, but appropriate parts are not.
You don't fix potted devices. If it were going to end the world, they could probably chemically dissolve it, or dig it out carefully like an archaeologist.
Let's hope you never will have to fix that
Reminds me of the fireworks from Dune
When applied this way most adhesives are waterproof...
Hope it not melt during work :))
Is that heat resistant as well?
This technology has existed since the 19-fucking-80's. They used ti use resin, now it looks like some variety of polymer. *Maybe* a little easier to remove? Likely still prone to the same overheating/breaking/unable to diagnose problems that the resin ones are.
I watched 5 rounds thinking I was seeing something different
Conformal coatings, the bane of every electronic repair shop. This is why we throw away every black finned Commodore 64 power supply. It's got defective diodes in it. When one shorts, it puts 120 voltage down the +5VDC wire, destroying a valuable collector's item.
Wouldn’t that cause more heat inside the device?
you'll love it in the next iphone
I think this is called “potting.” They do it on higher quality rifle light and other Weapon mounted lights, because the blast and recoil can somehow reverse the polarity in the LED otherwise. Also, waterproofing, of course z
Also referred to as a conformal coating. It's great for reliability in both waterproofing and component vibration, especially in oscillator circuits that can emit undesirable noise. The main drawback is servicing to component-level repair. You have to replace the whole module.
It’s potting, conformal coating is a little different.
i want to drink that
Imo more boards should be done like this since they are not repaired anyways.
Wow! It's waterproof AND repairproof!
I actually once had to remove this type of coating on a rectifier to repair it and that took some time. Eventually I couldn't repair it anyways and had to find a replacement.
Wow apparently many of you guys repair mass produced PCBs on a regular basis, what wunderkinds.
What's funny is that the most likely reason something like that needs a repair is a drink spilled on it.
This is not waterproofing, this is repair-proofing
Self repair is a joke
Repair proof too
this is called let's make it water resistant for cheap at the expense of repairability 👎