# How do you secure connectors onto boards?



## Phishfry (May 9, 2022)

It is very common to see embedded boards come with SATA connectors hot glued to board socket.
What do you like to use?
I have been using fingernail paint. I had some left over from my circuit board etching experiments.
Professionally I see a MilSpec Loctite for the purpose that is recommended.
I have also used blue painters tape on underside of drive connectors. Something to give it some strain relief.

What do you use to prevent connecter crawl?


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## Crivens (May 9, 2022)

5 min Epoxy with glass balls.


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## Phishfry (May 9, 2022)

I like that. Epoxy has that permanent bond.

I seen a video where they coated a board in fiberglass resin and ran it underwater for kicks.

Soldering on motherboards and Pi's I have learned the conformal coating can be the biggest obstacle to good solder repairs.
It really stinks when heated too.


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## Phishfry (May 9, 2022)

Just to pre-empt the jokers.
Chewing gum does not count.
I will take duck/monkey po as an answer. Also Silicone and Gorilla Glues.

What else? You could Tar it like potting. Maybe Rubber undercoating mix over the whole board?


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## aragats (May 9, 2022)

I like hot glue. It's easy to remove in case you need. I rarely use the gun, usually I heat the stick with a gas lighter ― the glue gets more fluid.


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## Crivens (May 9, 2022)

When you use a nitro based paint on one surface you end up with a bonding that can be cracked open with a screwdriver while still strong enough to hold everything. I used that in model airplanes to hold servos in the wing. Holds a catapult start but gives before the gears are damaged upon a lithobreaking event.


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## Phishfry (May 9, 2022)

How about the classic laptop sealant. That special yello-ish electronics tape. Flat connectors make it perfect.
You don't see laptop connectors crawling. So some of this is piss poor standard connector design.
Your HP/Dell/IBM would have a sticker over the ATX cable connector for some extra help. Even with a healthy connector ketch.

I just yanked a TPM module off a board that was bonded well. It was that experience that got me wondering.


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## jbo (May 9, 2022)

Phishfry said:


> What do you use to prevent connecter crawl?


There are specific products for these tasks such as Dowsil 744. Dow has an extensive catalog (PDF) of products for these sorts of endevours.

To directly answer your question: Most often I use Dowsil 744.


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## Phishfry (May 9, 2022)

Loctite 5140 potting and 5145 RTV was something that I read about. $40 bucks a tube is a non-starter.




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digikey does offer a $5 dollar alternative. Maybe I will bite on that.

I dont get it, why RTV silicone on these items? Like above I would expect superglue or epoxy. Maybe weld the plastics with solvent.

RTV is something I would expect to see in a bathroom. Not electronics.
Maybe mushy is good for this? I thought I wanted something with 3000psi bond.

Hotglue is the same. Its does not get that hard does it? Somewhat pliable.

I was thinking JB Weld. Its is a epoxy putty. I have used it to fill in small pits at work in a bind. Machinable.








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3900 Pounds of grip...


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## SirDice (May 9, 2022)

If it's loose and needs to be fastened, duct tape. If it's stuck and needs loosening, WD-40 

Don't do it much but prefer hotglue over any superglue/cyanoacrylate because it's easier to remove in this case. Cables can get snagged and break elsewhere might want to replace them in the future.


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## Phishfry (May 9, 2022)

Working with these railroad computers has me going clicky clackity. The ram is fastened down with a dohickey with thermal pads..


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## Jose (May 9, 2022)

Crivens said:


> ...Holds a catapult start but gives before the gears are damaged upon a lithobreaking event.


Did you mean "lithobraking"? It's funny either way


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## ralphbsz (May 10, 2022)

SirDice said:


> If it's loose and needs to be fastened, duct tape. If it's stuck and needs loosening, WD-40


If it moves, salute it. If it doesn't move, paint it olive drab.


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## Deleted member 70435 (May 10, 2022)

good has a whole chemical process in the formation of electronic boards. what I find interesting,








						www.ChemistryIsLife.com - The Chemistry of Circuit Boards
					

Introduction




					www.chemistryislife.com


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## Crivens (May 10, 2022)

Jose said:


> Did you mean "lithobraking"? It's funny either way


Both 
We had a case where a spade had to be used for recovery as the glider had reclassified as mole and had penetrated the surface by alost half a meter. Turns out the terminal velocity of a full carbon F3B bird is way faster than any skydiver. No one got hurt but the pride of the pilot, who had just looked away for a second, but then continued to steer the wrong plane.


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## Phishfry (May 11, 2022)

SirDice said:


> Cables can get snagged and break elsewhere might want to replace them in the future.


Yea but beyond TPM modules bonding I was reading about Mars Helocopter. Batteries near dead. Comms issue.
Solar Panels are blocked. Only 41% max battery acheivable and going into winter soon..
The article was talking about shifting the heater on at -30 degrees instead of -5 degrees(C).
Saving precious power. But they were worried about the off the shelf components used in what was supposed to be an experiment.
It has given much more. Directing the rover to better spots.








						After losing contact with its helicopter, NASA put the entire Mars mission on hold
					

Mars is only going to get colder and darker for the next 10 weeks as winter deepens.




					arstechnica.com
				




So I was thinking about connectors at -30 degrees in a harsh env. on a helo that was a test but now providing further research.








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Mars ain’t the kind of place to raise your kids. In fact it’s cold as hell – Elton John, Rocketman  Mars is hard. Only 26 of 56 missions sent to Mars have been successful. Landing on Ma…




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I know how military cable connectors are done as I have a friend who builds submarine electronics cable ends and another friend builds helo wiring harnesses. These are defiantly not off the shelf. Custom hand made and x-rayed. The wire is traceable.

Connectors can make or break you. How they secured the connectors on this helo could be the difference in mission extension or abandonment. Most off the shelf electronics 'extended temp' version is around -40 degrees. So the heater at -30 makes sense.

At that temperature I could see significant shrinkage. Plastic becomes brittle at these temps too. So maybe a floating joint with silcone or hot glue is better. It can expand and contract better because it is pliable.


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## Crivens (May 11, 2022)

Those conditiones are halfway extreme. One may ask the scientists in antarctica or folks in siberia for their experience. Also aviation, as -40 is pretty common at altitude. They may get away with -30 and no movement, but as soon as vibrations come in that is getting risky.


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## Profighost (May 11, 2022)

Some of the ideas mentioned here are what electronics profis also do, such as epoxy.

Hot glue is also working for many purposes, but I wouldn't recommend it as first choice. Like SirDice's tip with tape and WD-40 -  - it's more the kind of "quick&dirty".
It's quickly to use and easy to get (hot glue guns <5$ in every supermarket), but don't underestimate the temperature (all electronic parts have a max temp allowed [datasheet]) and you'll better get some professionell hot glue sticks. The ones coming with the gun mostly are cheap handicraft junk. The glue may lack of longterm stability.

Needless to say you need to ensure the stuff you use is electrical isolating, but what you also may keep in mind is:
- temperature you may bring on the electronics (hot glue)
- moisture; many are not aware of that many plastics are permeable to water. So using the wrong expoxy or glue may actually kill your board over time by storing water.
- some glues or potting compounds may are chemical agressive to the electronics (solder, solder, masks,... there's a lot of stuff on a pcb) corroding and killing the board.

Check professionell electronics distributers for professionell solutions e.g.:





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## Profighost (May 13, 2022)

Sorry, but I forgot the two most important points:

0. For SATA and HDMI (and maybe others) there cables available with their plugs having clamps.
They are good for the cables not loosing themselves, but not holding much stress. Of course I'm aware of on embedded system (Raspberry Pi or similar) the mini versions of the plug-connectros are used. And for them I don't think there are plugs with clamps available.

Most of all sockets today are just soldered on the PCB's tracks only (DON'T pull! )
The last plug-in connectors that can be fixed by screws are gone with the last VGA-plugs.
(In the 90s _all_ PC's plug-connectors were fixable with screws - at the housing, not the mainboard. But of course this can be done much cheaper...)

However:
1. First see to get a strain relief in the first place. Try to fix the cable mechanically (cord, cable tie, clamps, tape...) so no pulling force is getting to your plug'n'socket-connection at all.
All you do by any kind of glues or epoxy is to fix the stuff on your board directly. And what stress this can hold is very limited.
Points like moisture, heat, and corrosion are already mentioned, if you chose the wrong compound.
But above all the mechanical strength of the pcb itself and all its parts is also very limited. All layers like markings or solder stop mask are either  painted on, or like all copper are peelable laminate, which is also thermal sensitive. You don't want no PCBs tracks being lifted up. 

2. About coating your PCB:
Also always think of the fact that any coating has some effect on your board's thermal managemant, too!
There are coatings available with good thermal conductivity. But those mostly are very expensive and really nothing to be handeld by hobby handicraft enthusiasts (toxic fumes when drying!)
And in most cases they reduce the cooling of you board anyway, not seldom they are even very thermally isolating.
And it's not the processor only that needs cooling (in embedded cooling is done mostly passive, but the heat needs to be brought off in any case anyhow).
You have powerelectronics ICs on your board like voltage regulators, transistors and other parts like inductors or even (small) transformers. All current leading parts getting warm and depend on some cooling.

In many cases there is no problem.
All I want to say: Give it a good thought _before_ you drown your board into some plastics


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