A drop of ? to hold wires to board - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: May 26, 2017, 07:55:29 am
content: HiQuestionWhat is ? below.I want to put a drop of ? on my PCB to hold-down/secure 4 very this wires that I will soldered to pads on a 0.5mm pitch connector. Super glue is not a solution. Its a mess and it can damage the PCB surface and tracks if you decide to remove the wires.? makes only a small silicon/rubber like blob on the board that secures the wires to the PCB very well but when you remove it it does not damage the PCB.? Is readily available from most big electronics distributors.Thank you.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 26, 2017, 08:08:50 am
content: UV cure glue - sold for things like fishing lures. Sets in a second or two with UV flashlight.http://www.ebay.co.uk/itm/5-Second-Fix-UV-Light-Cure-Welding-Compound-Glue-Pen-Glass-Plastic-Repair-/122132871974?var=&hash=item1c6fafbb26:m:mjy1w4Pv303D22j4PvnRmBg

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 26, 2017, 09:27:03 am
content: Quote from: mikeselectricstuff on May 26, 2017, 08:08:50 amThis looks like fun stuff. But how does it compare to superglue? I remember pictures of modchipped games consoles with beautiful kynar wiring...Cableporn

author: Cicada
author_rank: Regular Contributor
timestamp: May 26, 2017, 10:18:02 am
content: HiI have used superglue in the past to fasten wires to a board. From what I remember it makes quite a mess. It flows easily so even a drop just spread all over. It also looks bad it makes a big white stain that almost look like some sort of crystallization formation.I cannot remember if I have ever tried to remove a wire fastened with superglue but my guess is that it will at least possibly remove the solder resist with it. If there are thin tracks beneath even the tracks. Not that one necessarily plan to remove a wire afterwards.I would just like to avoid superglue. I have being thinking about something like clear potting compound. I have seen a EEVBLOG tear down video where Dave used a screwdriver to pierce a clear potting compound on a high voltage board to reach a tuning pot or something. It closes up nicely after the screwdriver was removed. That look like a sturdy enough material to fasten a couple of wire with a drop.

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: May 26, 2017, 10:25:06 am
content: What about some hot glue? It should be good enough for your application. UV glue is also a great idea I've used it on a board once to secure a tiny wire to a PCB with great result.

author: cowana
author_rank: Frequent Contributor
timestamp: May 26, 2017, 10:25:53 am
content: A drop silicone adhesive such as Dow Corning 3145 would be the best option.http://www.dowcorning.com/DataFiles/090276fe801f97f8.pdf

author: CJay
author_rank: Super Contributor
timestamp: May 26, 2017, 11:08:48 am
content: Glass bond glue, it's the same as the UV stuff Mike mentioned IIRC, there's also superglue gel which is designed for wiring mods, TakPak I think they market it as, a two part pack with activator and glue.Both cure really quickly, I think the UV stuff would be easier to remove with less board damage...If you decide on a silicone make sure it's a neutral cure or you might find yourself with a board that's gone green, plus it takes quite a bit longer to cure than the other two.Hot Snot, it's cheap but it's difficult to make it neat and of course will fall off if the board gets too cold or will re-melt if it gets too hot.

author: Ian.M
author_rank: Super Contributor
timestamp: May 26, 2017, 12:17:24 pm
content: Bostik Impact Adhesive or similar - cures by solvent evaporation, unlike silicone it doesn't go bad in the tube so easily, dries to a rubbery consistancy so the wires can be ripped up with minimal risk of board damage.

author: dimkasta
author_rank: Regular Contributor
timestamp: May 26, 2017, 12:38:44 pm
content: You can try an adhesive tie wrap mount like those below. Mount it with double side tapehttp://www.panduit.com/heiler/ProductImages/wABMT-a-c20-o.jpghttps://gp1.wpc.edgecastcdn.net/00AC62/photos/151-31201_US_PROD01_sm.jpgIf you cannot find something small enough, perhaps you can super glue a hollow spacer and pass the cables through it

author: ajb
author_rank: Super Contributor
timestamp: May 26, 2017, 02:27:53 pm
content: Quote from: Cicada on May 26, 2017, 10:18:02 amLow viscosity superglues will have these problems, but you can get CA glues in thicker viscosities, up to a gel consistency. The thicker formulations cure more slowly and so tend not to leave white clouds in the vicinity. A good hobby store will likely have three or four different formulations to choose from.That said, if you want something removable, superglue is probably not the best choice.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: May 27, 2017, 12:25:30 am
content: If I want to affix something with a flexible rubbery type of gap filling glue I use the stuff that is called "shoe goo" or "Amazing Goop". Widely available in north America, I think they are the same just different brands. They appear like clear greasy silicone rubber out of the tube and contain perchloroethylene as a solvent which evapourates. Easy to apply and control, you can use a toothpick to direct tiny blobs where needed. The perc solvent does attack plastics and rubber and this can be to an advantage if gluing layers of a sneaker. On a pcb so little will go into the board that I don't think it matters

author: PointyOintment
author_rank: Frequent Contributor
timestamp: May 27, 2017, 12:50:42 am
content: Where I live, Home Depot, probably other hardware stores, and even Safeway (a grocery store) carrythis gel superglueamong other options. I've carried it in my backpack for years. It's very good for closing cuts, sealing torn fingernails, etc., because it cures within a few minutes and doesn't flow everywhere. It would hold wires to a PCB, and wouldn't make a mess, but it would be hard to remove cleanly. I did try using in place of solder to connect wires to a PCB once (because my soldering iron was packed away, I think). That didn't work.

author: DTJ
author_rank: Super Contributor
timestamp: May 27, 2017, 02:33:49 am
content: Use cheap clear nail varnish or even green stuff to be fancy. $2 per bottle.If you leave the lid off the bottle for a few hours the solvent evaporates thickening up to your preferred consistency.

author: xrunner
author_rank: Super Contributor
timestamp: May 27, 2017, 02:46:42 am
content: Quote from: mikeselectricstuff on May 26, 2017, 08:08:50 amOh how have I missed this? I gotta have that going to Ebay right now!

author: KL27x
author_rank: Super Contributor
timestamp: May 27, 2017, 04:44:10 am
content: Swear the OP read like a jeopardy question for "what is hot glue?"Usually, the esthetics and strength doesn't matter much. You're not gonna see it or care if it falls off, later. It just has to hold together long enough to get the boards back in the enclosure, lol. After that, the wires aren't going to need the strain relief, anymore. But FWIW, if you find a good hot glue, it can be essentially permanent barring solvents or obviously high temp. And if it doesn't look neat enough the first time, drop of alcohol, pull it off, and do it again.I have one of the adjustable temp guns; I keep the temp where I can touch the bead without burning myself. It can remain on, constantly, without burning the glue.

author: P90
author_rank: Frequent Contributor
timestamp: May 27, 2017, 04:54:41 am
content: yellow-ish high strength hot glue.

author: KL27x
author_rank: Super Contributor
timestamp: May 27, 2017, 05:14:02 am
content: Hot glue can be very neat, too. Where the esthetics matter, I am pretty accomplished at molding hot snot with packing tape to get smooth contours and trimming with a razor sharp knife (sticky side of the tape goes on the glue, if you want it to peel off!). You have limited window to get it right, but it's probably the most amazing stuff on the planet for prototyping, repairs, and the like. For certain things it can be made very, very permanent.

author: nikonoid
author_rank: Regular Contributor
timestamp: May 28, 2017, 01:13:17 am
content: At work we use a glue called E6000. It is great that it grips to most smooth and porous surfaces. It is clear, so looks good. When dried, it behaves like a clear rubber, so you can always remove it without damaging anything. It is also temperature and water resistant.Sent from my iPhone using Tapatalk

author: P90
author_rank: Frequent Contributor
timestamp: May 28, 2017, 01:44:38 am
content: Quote from: nikonoid on May 28, 2017, 01:13:17 amthat stuff contains Tetrachloroethylene, not the most toxic chemical, but still, I'd stick with hot glue...

author: vk6zgo
author_rank: Super Contributor
timestamp: May 28, 2017, 01:47:29 am
content: Back in the late '70s/early '80s I attended a course in "High Reliability Hand Soldering".Among many other things, we were introduced to an adhesive which was specially designed to attach wires to a PCB.It worked extremely well, with no grotty "mess" like that from "Super Glue".From memory, it was marketed by Pace, but it might have been some other supplier.Maybe because there is less need to make PCB modifications now, (or perhaps because it contained something nasty), this product seems to have vanished from the market.

author: P90
author_rank: Frequent Contributor
timestamp: May 28, 2017, 02:35:12 am
content: Quote from: vk6zgo on May 28, 2017, 01:47:29 amI seem to recall we used some sort of yellow contact cement in the old days...

author: SeanB
author_rank: Super Contributor
timestamp: May 28, 2017, 08:56:58 am
content: I would go with the UV cure glue, as it is available with decent price, and will cure nicely with UV light in a few seconds, so you can align the wires before hitting the torch to it. The silicones are good, providing you have the time for the reaction to complete and enough oxygen in the silicone to polymerise it.As an alternative 5 minute epoxy is good, reasonably fast and can be done with a pack of bamboo skewers to grab a drop out of a small dollop of each type, and then mix on a small piece of waxed paper. Dispose of each skewer after a single use, and you will need 2 per batch, one per blob of epoxy mix, and then use only the one to mix them and apply the drop before it cures. Fastest cure I find is the Pratley quickset steel or white, it will cure fast, and the clear is the slowest.I really would not use hot melt glue, many of the formulations they are made from have very poor long term properties, they tend to react chemically with time and temperature, forming either a conductive film on the surface or corroding the copper wires and board. The yellow contact adhesive does the same, though it also likes to do both at the same time, and the solvents in it will destroy electrolytic capacitors by damaging the rubber seal and allowing the capacitor to lose electrolyte faster.Superglue I used a lot to bond wires and fix traces, just use the gel types, and simply use masking tape ( painters tape in the USA) and cut paper masks to mask off most of the board so the bloom it creates ( evaporating light components of the glue) is easy to clean afterwards. Using the activator spray in areas with low humidity also helps, but here at the coast I am a lot more concerned with keeping it in the fridge so it does not cure in the bottle, than to really use an activator on it.

author: Ian.M
author_rank: Super Contributor
timestamp: May 28, 2017, 09:05:04 am
content: The glue to avoid at all costs is that yellow foaming glue that sets fairly hard. It used to be used in a lot of consumer electronics, and was an absolute disaster - worse to remove than well bonded silicone, and tended to become conductive with heat and age to the point that you'd get runaway carbonisation if it bridged two conductors with a high enough voltage difference. Its breakdown products could also attack copper . . . .If you see it and its gone brown you know you are in for a PITA of a job trying to remove enough of it to halt the damage.

author: KE5FX
author_rank: Super Contributor
timestamp: May 28, 2017, 09:33:46 am
content: I like to use Devcon 5-minute epoxy for this sort of thing. It sets quickly, dries clear, and doesn't promote corrosion. It's also easy to remove with a heat gun.It's a pain to mix up a batch every time you want a couple of drops, though. Going to order one of the Bondic UV pens and see how it works...

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 28, 2017, 12:56:35 pm
content: Quote from: KE5FX on May 28, 2017, 09:33:46 amThe double-barrel syringe packs are handy for when you only want small amounts

author: KL27x
author_rank: Super Contributor
timestamp: May 28, 2017, 07:10:08 pm
content: Tip for mixing small amounts of epoxy... save the q-tips/sticks. A small chisel or razor blade over end grain cutting board (or glass if you don't mind dulling a chisel/blade). Spread it out into a long thin, sub micron thin smear. Then scoop it up perpendicular to the smear, picking up just small bit of the smear at a time, stacking each layer of poorly mixed, streaky epoxy next to each other on the blade. Now you have lots and lots of streaks in a stackup blob, like layers of damascus. Spread this out again, into the long smear, mixing all these layers into each other. 3 or 4 repetitions will make a perfect mix, and you don't waste any epoxy. Just pick it up a little bit at a time to make a big fat blob on just the side of the chisel, use it, and wipe the blade with a paper towel when you're done.It's not uncommon I use all the epoxy I mixed. Or maybe I run out and have to mix up a tiny little bit more. I stretched one tube of JB weld for a decade. The caps had fallen apart, and I was closing the tubes with a piece of plastic tied over with a string, lol.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: May 28, 2017, 09:34:03 pm
content: Quote from: cowana on May 26, 2017, 10:25:53 amWhen using silicone RTV, choose one that doesn't produce acetic acid while curing.I got a neat tip from a friend on hot melt glue - it softens in isopropyl alcohol, useful when cleaning it off a board.

author: KL27x
author_rank: Super Contributor
timestamp: May 28, 2017, 09:48:53 pm
content: QuoteThis is one of the properties that makes it the most amazing thing in the universe. On smooth surface, a drop of alcohol makes it peel right off. In a blob of wires/fibers, alcohol softens the glue, making it tear and crumble more easily.Hot glue is strong enough to use in finish carpentry in place of nails or conventional glue. It is strong enough to do a lot of things. But in many cases, is it possible to deconstruct hot glue joints relatively easily without any damage to the original parts. Hot glue is holding together a LOT of things in my workshop and in my electronics prototypes. Particularly when you are trying to figure out exactly where a tool holder, a button, a switch, etc needs to go and have to experiment with placement.Conversely, where the parts that are joined are very rigid and there is no room for flex, even exposure to solvent won't separate the bond. Cell phone screens are held on with what is basically a very thin layer of hotmelt glue. With right techniques and application, hot melt is very versatile.

author: P90
author_rank: Frequent Contributor
timestamp: May 28, 2017, 10:00:10 pm
content: Quote from: KL27x on May 28, 2017, 09:48:53 pmdon't forget hot glue is also very handy as a sort of "clamp" to hold things in place while the silicone or construction adhesive sets.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: May 29, 2017, 01:47:58 am
content: E6000 is by far the best glue I have ever seen. I glued a rear view mirror onto an old BMW and drove it 180kph with no issues. Originally purchased it to bond the plastic frame to the glass of an iPhone when refurbing the LCD's. I keep it around for everything now.Quote from: nikonoid on May 28, 2017, 01:13:17 am

author: Cicada
author_rank: Regular Contributor
timestamp: June 14, 2017, 09:25:19 am
content: HiThank you for all the suggestions. I have changed the scope of the modification a bit. I originally planned to glue individual wires to the PCB but later decided to use a multi core cable instead. I got a hold of this.http://www.go-araldite.com/products/epoxy-adhesives/araldite-standard-2-x-15ml-tubeIt looks very nice, is very cheap and is not messy to work with. I am sure this will work for individual wires but it will be a bit difficult to group the wire together and hold them down on the board because the epoxy sets very slowly. I.e. 24 hours. So one will have to group individual wires in a sleeve which will not always be possible.Thanks

author: xrunner
author_rank: Super Contributor
timestamp: June 14, 2017, 11:07:22 am
content: I got a tube of UV glue and a UV light. Tried it on some wires on a PCB. I gotta say, I'm never going back it works great!

author: DTJ
author_rank: Super Contributor
timestamp: June 14, 2017, 11:11:24 am
content: Quote from: xrunner on June 14, 2017, 11:07:22 amFrom eBay?Got a link or brand info?Cheers.

author: xrunner
author_rank: Super Contributor
timestamp: June 14, 2017, 11:23:08 am
content: Quote from: DTJ on June 14, 2017, 11:11:24 amSure. I got the UV pen + light off Ebay. I later got a little better UV light, just because it was so cheap, but it still works OK with the el-cheapo light the pen came with. Just put a small dot of the glue on top of the wire on the PCB and 6 seconds of light - presto. Looks really professional and it sets up nice.UV glue pen + lightUV light

author: mariush
author_rank: Super Contributor
timestamp: June 14, 2017, 11:40:05 am
content: How about a drop of that Loctite thread locker solution, you know the kind you put on screw threads usually to prevent them from loosening over time?Not quite the intended purpose but i suppose it dries out quickly and should be quite "sticky" and you should be able to pull the wires relatively easily (the solution should resist torque but not other forces, unless i'm wrong)

author: xrunner
author_rank: Super Contributor
timestamp: June 14, 2017, 11:43:09 am
content: Quote from: mariush on June 14, 2017, 11:40:05 amIt doesn't "dry" in the open air, has to be between tight spaces like screw threads.

author: mariush
author_rank: Super Contributor
timestamp: June 14, 2017, 12:02:16 pm
content: So wouldn't it "dry" quickly between the ribbon cable and the circuit board? Just put some pressure on the cable for a few seconds?

author: CJay
author_rank: Super Contributor
timestamp: June 14, 2017, 12:24:32 pm
content: Quote from: xrunner on June 14, 2017, 11:23:08 amMost useful, thank you, you can also buy refills for the pens for ~$1.40 so if you have a suitable UV light already...

author: kalel
author_rank: Frequent Contributor
timestamp: June 14, 2017, 12:40:31 pm
content: Quote from: CJay on June 14, 2017, 12:24:32 pmI always wondered about the quality of these. They offer cheap UV glue bottles for cellphone repair. E.g. this for $1.26http://www.ebay.com/itm/Useful-UV-Glue-LOCA-Liquid-Optical-Clear-Adhesive-replacement-tools-5ml-M35-/291641635172- Paired with an UV light, it should produce the same results, but maybe the pen provides more accurate control, I don't know.

author: CJay
author_rank: Super Contributor
timestamp: June 14, 2017, 12:58:15 pm
content: Quote from: kalel on June 14, 2017, 12:40:31 pmI think for this use, the pen would be preferable, the cellphone repairers aren't that bothered about precise spots of adhesive, they want complete unblemished coverage so I reckon the pen would be more controllable.

author: xrunner
author_rank: Super Contributor
timestamp: June 14, 2017, 01:28:38 pm
content: Quote from: mariush on June 14, 2017, 12:02:16 pmNot in my experience. It doesn't set up (dry is not the right term to use I think) like that. I've left it out for days because I thought the same thing, and it simply does not "dry". It has to exist between airtight spaces that are compressed. Try it yourself.

author: xrunner
author_rank: Super Contributor
timestamp: June 14, 2017, 01:30:16 pm
content: Quote from: kalel on June 14, 2017, 12:40:31 pmDon't use the cellphone repair UV glue! It doesn't set up hard. It cures like a jello consistency and is not strong in small amounts like the hard stuff is.

author: R005T3r
author_rank: Frequent Contributor
timestamp: June 14, 2017, 03:59:31 pm
content: Cellphone UV glue is used as a weak adhesive and is used for potting the glass... If superGlue or hot glue are not an option, I'd look for a Loctite Adehesive especially suited for electonics or a liquid gasket... Something designed for both vibration and with a good temperature resistance.

author: stj
author_rank: Super Contributor
timestamp: June 15, 2017, 02:57:15 pm
content: the best thing for tacking wires down is actually UHU or Bostik adhesive.it dries into a water-clear slightly flexable plastic.it wont crack or vaporise into your eyes if you use an iron near it after.and you can peel it off clean if you really have to.

author: CJay
author_rank: Super Contributor
timestamp: June 15, 2017, 03:19:58 pm
content: Quote from: stj on June 15, 2017, 02:57:15 pmJust like the UV stuff then except it takes longer to cure.

author: stj
author_rank: Super Contributor
timestamp: June 15, 2017, 03:46:14 pm
content: and costs a lot less - i get big tubes in the £ shop