[SOLVED] How to remove/clean off these annoying glue easily ? - Page 1
Forum section: electronics / projects

author: BravoV
author_rank: Super Contributor
timestamp: November 30, 2016, 03:39:11 am
content: Update : Solved the problem, not perfect though, but workable at post #31 ->HERE, thanks to SeanB for the tip.Spent almost 30 minutes scraping and yanking it with needle without any luck (pointed by red arrows).This yellowish glue can not be peeled easily, they just chipped off tiny piece by piece when I yanked them with sharp needle. Also its somehow sipped in and perfectly secured at the tiny latches at the connectors.Is there any easy and non destructive way/method to clean this yellow gunk ? Any idea please ?All I want is to pull these connectors off the board.Attached photos below.

author: Cerebus
author_rank: Super Contributor
timestamp: November 30, 2016, 04:56:55 am
content: It's hot melt adhesive. If you're lucky a hair drier will warm it up enough to make it sufficiently elastic to pull off. If not, you're going to have to find a heat gun with a good enough thermostatic control that can melt the glue but not the connectors or cable insulation. One of the cheap hot air soldering guns might be just the ticket - mine goes down to a well-controlled 100C.

author: xavier60
author_rank: Super Contributor
timestamp: November 30, 2016, 09:47:19 am
content: That looks like the same stuff I first saw in electronic products over 30 years ago. High temperature causes it to turn brown. It also becomes corrosive and conductive. It is responsible for causing many premature faults.

author: wraper
author_rank: Unknown
timestamp: November 30, 2016, 10:35:09 am
content: Quote from: Cerebus on November 30, 2016, 04:56:55 amNo it is not. But it should become softer and easier to remove when heated.

author: deejay2k1
author_rank: Newbie
timestamp: November 30, 2016, 10:39:05 am
content: try isopropyl (rubbing) alcohol. see if it softens the goo.or try to score along the mating of the connectors with a sharp blade (exacto knife)

author: CJay
author_rank: Super Contributor
timestamp: November 30, 2016, 12:35:22 pm
content: It's some sort of rubber adhesive, I've not found any easy way to remove it but I have been told lighter fluid/naptha will soften or dissolve it.Would be worth trying to dissolve some of the bits you've scraped off in a small pot of naptha.

author: Cerebus
author_rank: Super Contributor
timestamp: November 30, 2016, 01:01:56 pm
content: Quote from: wraper on November 30, 2016, 10:35:09 amJust blindly gainsaying someone else by blankly offering a definitive sounding "is it not" without providing any further information as to what itis, is not helpful. It makes it sound like you're looking for an argument rather than trying to help the OP.

author: Unknown
author_rank: Unknown
timestamp: November 30, 2016, 04:45:35 pm
content: Quote from: CJay on November 30, 2016, 12:35:22 pmIf it's a polyurethane glue, acetone will act as a solvent. If the naptha doesn't work, try acetone. Be careful, some plastics don't tolerate acetone.

author: SeanB
author_rank: Super Contributor
timestamp: November 30, 2016, 06:19:58 pm
content: Freeze it with freezer spray, then it becomes brittle and breaks off easily. Solvents tend to make it soft yes, but it then spreads all over the place. Freeze and it just breaks off with slight movement or prodding.

author: wraper
author_rank: Unknown
timestamp: November 30, 2016, 06:39:41 pm
content: Quote from: Cerebus on November 30, 2016, 01:01:56 pmWhat is not helpful, is when someone provides false information blankly saying it is hot melt glue. As of what particular formulation of this glue is, I don't know. But that does not matter that much. What I know, I've seen a lot of boards with such glue, andit is not hot melt, therefore won't melt when heating.

author: BFX
author_rank: Frequent Contributor
timestamp: November 30, 2016, 07:07:59 pm
content: Quote from: SeanB on November 30, 2016, 06:19:58 pmThis is really good way.

author: Cerebus
author_rank: Super Contributor
timestamp: November 30, 2016, 09:52:57 pm
content: Quote from: wraper on November 30, 2016, 06:39:41 pmYup, that sounds just like someone who is merely looking for an argument. Another one for the ignore list...

author: wraper
author_rank: Unknown
timestamp: November 30, 2016, 10:26:58 pm
content: Ok, if you never seen how hot melt glue looks like, then keep thinking I'm here to try argument with you. I'm out, +1 for ignore.

author: BravoV
author_rank: Super Contributor
timestamp: December 01, 2016, 04:51:22 am
content: Thanks for the suggestions guys, really appreciate it.I will try these following the current possible methods ..- Freezer spray 1st as SeanB suggested, hopefully it will become brittle.- Warm method, then try to pick and scrap it, must be tedious as this is quite small.- Zippo fluid , with cotton bud when applying to soften it.- Acetone, this is quite risky as the connectors are plastic, must be really careful when applying it.Last effort , de-solder the whole connectors to lift them up altogether.Will report back the result.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 01, 2016, 07:16:52 am
content: Quote from: Cerebus on November 30, 2016, 09:52:57 pmYou are not contributing. It can't be so hard to have the wrong answer. It happens to all of us! Now, please, just go away and stop producing more of that shit.

author: CJay
author_rank: Super Contributor
timestamp: December 01, 2016, 08:09:17 am
content: Life lessons learned, when proven wrong, try to bite your tongue, admit it gracefully, apologise if necessary and learn from the mistake.On occasion I've had to take a craft knife to that glue to separate connectors, it's horrible stuff and makes disassembling things difficult (which is, I suppose, testimony to its effectiveness) but I wouldn't bother too much about removing it from the connectors as long as it's not in contact with any conductors or close to high voltages, it simply won't be a problem in those circumstances.I would make efforts to remove it if it was in contact with component leads, PCB tracks or close enough to high voltages that it could cause leakage.

author: Cerebus
author_rank: Super Contributor
timestamp: December 01, 2016, 01:12:27 pm
content: Quote from: Siwastaja on December 01, 2016, 07:16:52 amActually, I already had. You're the one now stirring up something off topic and choosing to use language that makes it difficult to just ignore you. You might consider moderating your tone.I've no problem with being wrong, I have been most of my life about something or other. What I have a problem with is someone who (and I've seen this repeatedly done to others) just flies past saying "you're wrong" without contributing anything to move the conversation towards its goal or any evidence that excluded my suggestion - just a bald, pointless, unhelpful "It's not...". That's just unhelpful and I said so. Is that so wrong? And once it has clear that someone just wanted an argument, he got added to my ignore list and, well, I ignored him.This is my final word on the topic. Be the big man and make it yours too.

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2016, 01:59:53 pm
content: Come on guys, play nice!@Cerebus: wraper's postings do often come across as rather terse and black and white, I hope it's a linguistic thing, I'd have great difficulty coming across easily in Latvian. I've had a similar situation (It's an NTC, not it's a VDR) in the past and chose to ignore it. ...and you did say point blank that it was hotmelt, which it almost certainly isn't... that's the clear stuff with dangling 'cobwebs.@wraper: Your replies do sometimes come over a bit short and 'point-blank' (it was an NTC, not a VDR by the way). Maybe you could try to soften it a bit (stick an 'I think' on the front).

author: wraper
author_rank: Unknown
timestamp: December 01, 2016, 02:45:01 pm
content: Quote from: Gyro on December 01, 2016, 01:59:53 pmI can be too harsh sometimes, and acknowledge it does not add any credit to me. Although, in this case I certainly didn't write anything ill intended by quoting that hot melt, and reply was completely blown out of proportion IMO.QuoteDon't recall correcting you about NTC. Only recall there were a few occasions people named blown part as a MOV while it actually was NTC.

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2016, 03:06:18 pm
content: Yes, out of proportion, I guess people have days like that.. I know I do!QuoteNot worth worrying about now - It was that guy who had the fuse blow, so jumpered it and had UV fireworksYou were convinced in very few words that it was a MOV. We didn't reach flashpoint anyway.Edit: Oops, actually the other way round (NTC)

author: wraper
author_rank: Unknown
timestamp: December 01, 2016, 03:19:54 pm
content: Quote from: Gyro on December 01, 2016, 03:06:18 pmAbout UV PSU guy, I certainly recall saying it was NTC which was glowng.Found, here it is:https://www.eevblog.com/forum/repair/power-supply-failure-(with-ultraviolet-radiation)/msg1060769/#msg1060769, and it was you who were convinced it was MOV. Seems that was MOV in the end, however there was R3 marking on the PCB. About short posts, it's certainly easier for native speaker to write some long texts without spending awfully lot of time.

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2016, 03:53:35 pm
content: Ah, yes, that was the one. Happy days!Yes, first time I've seen a MOV with an R reference (I guess the considered it a VDR rather than MOV?).Yes I think people need to have more awareness of non-native speakers and not see short posts as 'rude' or agressive. It would help if more people started using country flags too (and looking at them!), usage seems to be dropping off again in new members.

author: wraper
author_rank: Unknown
timestamp: December 01, 2016, 04:29:57 pm
content: Quote from: Gyro on December 01, 2016, 03:53:35 pmDunno, it's one and the same. Usually I see something like RVxx, marking it as Rxx is certainly uncommon.Quote

author: Gyro
author_rank: Super Contributor
timestamp: December 01, 2016, 04:31:42 pm
content: Yup.

author: KL27x
author_rank: Super Contributor
timestamp: December 01, 2016, 06:17:15 pm
content: If it WAS hotmelt, it would easily peel off in one piece with a drop of alcohol. Heating it would just make a mess. It sure looks like a polyurethane glue.

author: gnavigator1007
author_rank: Unknown
timestamp: December 01, 2016, 06:48:22 pm
content: Quote from: KL27x on December 01, 2016, 06:17:15 pmBeen my suspicion as well. I've attacked it in the past with files, knives, and sandpaper. Real pain in the ass. Came across a board few months back covered in this stuff with hot melt completely covering itTook me forever to clean the damn thing up. I did find this:http://crosslinktech.com/support/tips-and-tricks/how-to-remove-cured-epoxy-or-polyurethane.htmland this sounds promising:http://www.dynaloy.com/products/urethaneFor now I'll be sticking with the cutting/scraping method, but hope somebody finds something better that doesn't cost $200+ a bottle

author: Corporate666
author_rank: Unknown
timestamp: December 01, 2016, 09:43:00 pm
content: Quote from: Cerebus on December 01, 2016, 01:12:27 pmReading the thread, it appears you need to relax. I didn't see anything rude of condescending or argumentative whatsoever in his first post. He just said "no, it's not"... he did offer additional information - he said it won't soften with heat. The only offense was what you read into it and chose to challenge him on and claim he was looking for an argument. You also made sure to tell him you were putting him on ignore - making sure to get the last word in without giving him a chance to reply. That's rude and argumentative in my book.Anyway, Bravo... did you have any luck getting that stuff off? I have found IPA works, but only if you soak it for a looooong time, like days. Acetone works, but will absolutely damage plastic parts because it also needs to be soaked for some time. It will also damage PCB's due to the length of soaking time required. Something in the middle might work... maybe flux cleaner. I like the freeze spray idea.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 02, 2016, 07:21:20 am
content: Quote from: xavier60 on November 30, 2016, 09:47:19 amThat's my experience too. My whole life I've loathed this stuff and wondered why manufacturers keep using it. Deliberate planned obsolescence electronics-poison maybe? I posted something a few months ago about some WiFi nodes I'd been given that were dead due to this vile stuff and its corrosive-conductive effects.It's something solvent based, judging by the way it shrinks surface-first. You can see that effect in the final pic, where a bit looks like it has tendons.Definitely not hot-melt, which doesn't shrink as it cools.Sometimes you can cut/peel it off by gripping with the jaws of fine wirecutters. But it's very tenacious.With age and heat it goes darker brown, becomes very corrosive, and I think a little conductive.Whether it's rubber or urethane based, no idea.

author: salbayeng
author_rank: Frequent Contributor
timestamp: December 02, 2016, 09:30:12 am
content: Hi this type of adhesive is very similar to "contact cement" , basically a synthetic rubbery type compound.Also similar to "no more nails" and similar construction adhesive.Polyurethane doesn't shrink or make the stringy bits seen in the photo.Xylene or Toluene are the original solvents, and while these will soften & dissolve the adhesive, it will just turn into a sticky mess (like chewing gum).These solvents are OK on the hard plastics used in electronic assemblys, but will make PVC swell, and possibly go brittle later.

author: 2N3055
author_rank: Super Contributor
timestamp: December 02, 2016, 09:55:50 am
content: It is neoprene based glue, used because it is elastic, sticks like crazy, and cheap as dirt... It is applied with a brush, cheap and easy..It is very good to vibration proof (because of elasticity, basically you rubberize things)..It is a pain to remove. There are solvents, but very aggressive (and toxic) to everything else ..Cooling(freezing) and breaking of pieces and cut with scalpel works best for me.. And lots of patience...Sometimes connectors or other stuff will be easier to replace than to clean ..It used to be used a lot on far East consumers electronics 20-30 years ago, not so much any more luckily...

author: grifftech
author_rank: Frequent Contributor
timestamp: December 02, 2016, 03:31:54 pm
content: Quote from: SeanB on November 30, 2016, 06:19:58 pmupside-down canned air would work too

author: BravoV
author_rank: Super Contributor
timestamp: December 02, 2016, 04:06:39 pm
content: Updates ....I decided not to use any solvent, as this glue is so sticky, worry it will soften too much, and part of it got dissolved more in the solvent, turning into lower viscosity liquid that might sip in under the connector's pins, or spread and run under the surrounding smd components, and worst created a soft new sticky layer of this nasty glue covering the board area.Also possibly it will turn into corrosive substance as others pointed out at later date, definitely a no no.Thanks to SeanB on the idea of freezing the glue, yes, it works, but not perfect though. It still needs quite some elbow grease, but the work is significantly easier than before.The reason is, once the glue is freezed, the picking/yanking/scraping process will be a lot easier, as bigger sized chunks just came off rather than small pieces by pieces which is really painful task to do.I will just let the photos to tell the story ...Here a TO-220 chip as size reference, just watch closely the small pieces that I put on the IC's pin, those are the pieces that chipped off when its at room temperature.I used this technique as I think its effective, 1st, use a sharp needle point to tear down or penetrate the glue, beware of PCB traces or any other weak surface if any below the glue. Once penetrated and torn, use a sharp tweezer to pull or sort of yank it off thru the glue opening.The push pin needle, and the sharp tweezers are the tool I need to get the job done. The serrated tweezers will make it bite & grip the glue stronger, and wont slip off easily compared to non serrated one. Again, TO-220 as size reference for you to imagine the size I was working on.An improvisation, as I don't have freezer spray, I used the butane cartridge from the portable stove, and the nozzle from my shaving cream.LOL ... It freezed out the glue effectively on a really short burst. (yes, I tried it at other part 1st) Don't worry, did it at my back yard windy garden with open sky.Warning to other readers, using the butane gas this way, is very-very dangerous as its highly inflammable, and I am not responsible for any accidents that may harm or kill you or burn down your house. And remember, if you're going to use this method, make sure you do it out door in a well ventilated place.Hope this will be useful to others someday.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 02, 2016, 04:52:27 pm
content: Quote from: BravoV on December 02, 2016, 04:06:39 pmThis time of year for a great many users of this forum the solution is simple. Just go outside. No need for repeated freezing, it stays cold.For a great many others the answer is to wait 6 months before working on this board.For those living in the middle, you have my sympathies.

author: donmr
author_rank: Regular Contributor
timestamp: December 02, 2016, 06:19:24 pm
content: Even those in the middle lands have freezers they can put a small board in for a while.

author: salbayeng
author_rank: Frequent Contributor
timestamp: December 02, 2016, 10:19:42 pm
content: More on the propane freezing approach.The wart freezing kits at pharmacies just use propane/butane, with an extension tube about 1.5mm ID, and a piece of foam stuck on the end.These are a bit expensive to buy for freezing glue, but you can make the same apparatus yourself, the piece of foam on the end is the secret, it stops all the liquid going everywhere, and by evaporating off at the foam, and "auto refrigerating" it creates a reservoir of cold liquid in the foam you can just drip off /dab onto the offendingwartglue.http://dermaltherapy.com.au/products/foot-care/warteze.The actual amount of flammable gas produced with a bit of foam on the end is low enough to be used safely indoors.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 03, 2016, 05:24:17 am
content: Quote from: BravoV on December 02, 2016, 04:06:39 pmthere corrected for you. it can be spotted easily by anybody here, just in case for any kids out there who have little clue what butane gas is... and this is safety life threatening issue so i think its necessary to make a simple typo check. btw another suggestion as freeze agent is the co contact cleaner... its just as flammable, but more specific to electronic use... and i believe its more freezing than butane liquid, ymmv..and lastly, i can certainly confirmed the yellowish goo is not simply a household holtmelt glue. i usually just scrap them off bit by bit with sharp tip knife or tweezer if i have to.

author: helius
author_rank: Super Contributor
timestamp: December 03, 2016, 05:37:50 am
content: Quote from: Mechatrommer on December 03, 2016, 05:24:17 am"inflammable" is the correct term. It does not come from adding "in" to "flammable", but rather from the Latininflammo, inflammare, inflammavi, inflammatus sumwhich means to ignite.

author: KL27x
author_rank: Super Contributor
timestamp: December 03, 2016, 06:47:53 am
content: QuoteAwesome info. I think I always assumed it was just a quirk of English. The same way "shelled peanuts" are the ones that have been shelled (here we go again; "shelled" meaning the shell having been removed).OP, I would have thought an Exacto, or similar, would have been helpful, too. Along with the freezing and pin and ridge-tooth tweezers. Great job on the writeup. Good to know.

author: SeanB
author_rank: Super Contributor
timestamp: December 03, 2016, 08:54:00 am
content: On a similar vein I have been removing hard drive magnets from the pole pieces. So far only one was not stuck down, so the whole lot has been sitting for a week in a bottle of MEK solvent. This does dissolve the locking adhesive after a while, though it is fatal to the little pieces of plastic that were on there as head lifters and such, they turned into powder after swelling up. Got about 10 magnets off now, still have around 20 to soak through.

author: IanB
author_rank: Super Contributor
timestamp: December 03, 2016, 09:24:43 am
content: Quote from: helius on December 03, 2016, 05:37:50 amBoth flammable and inflammable are in the dictionary. They both mean the same thing, "easily set on fire".

author: BravoV
author_rank: Super Contributor
timestamp: December 04, 2016, 12:24:51 am
content: Quote from: Mechatrommer on December 03, 2016, 05:24:17 amInteresting suggestion, just fyi, I own that "exact" contact cleaner as you pointed out above, my finding is when it comes to freezing capabilty, the butane liquid when evaporates, beats my contact cleaner liquid out of the water. In my test, its simply no contest, butane liquid win.For example, just two or three short burst of butane liquid at the pcb, the other side of the pcb starting to form and grow "freezed" ice flakes, so not just condensation, really white ice flakes.Here is my contact cleaner vs the butane cartridge vs my shaving cream.

author: BradC
author_rank: Super Contributor
timestamp: December 04, 2016, 12:33:23 am
content: Butane evaporates at about -1C. isobutane evaporates at about -10C and Propane evaporates at about -40C.I use Propane for shrinking mechanical parts for an interference fit and butane or isobutane for freezing depending on what I have around.A serious blast of liquid propane from an up-turned 9kg BBQ cylinder has serious cooling potential though, although the mercaptan *stinks*.I have some kit that removes the mercaptan but the resulting product is time and equipment intensive.

author: BravoV
author_rank: Super Contributor
timestamp: December 04, 2016, 01:16:14 am
content: Quote from: BradC on December 04, 2016, 12:33:23 amHmm ... propane .. now I know which friend to visit if I need instant freezing at small spot.

author: Sceptre
author_rank: Regular Contributor
timestamp: December 04, 2016, 02:25:54 am
content: The yellow glue that plagues repair techs and hobbyists is chloroprene (neoprene) adhesive. Google 'remove yellow glue pcb' for links to discussions. Two from sci.electronics repair:https://groups.google.com/forum/#!topic/sci.electronics.repair/0M6NpItdfSMhttps://groups.google.com/forum/#!topic/sci.electronics.repair/nYve09tYKwY(The second thread has some useful information before it descends into name-calling...)Summary: some contact cleaners (Servisol 160, RS 180-847) soften the glue enough to make removal possible (though still tedious). The active agent is probably cyclohexane. This chemical compatibility chart indicates that chloroprene has poor resistance to cyclohexane:http://www.usascientific.com/pdflit/Chloroprene%20Resistance%20Chart.pdfAbout a year ago, I worked at removing this glue from a broken Roku Soundbridge switching supply. The toastier areas had resistance in the megohm range (though I don't know whether any high-impedance circuits were affected; it ended up needing a small electrolytic replaced). After doing the research above, I got some naptha (white gas / camp fuel) which contains about 15% cyclohexane. It worked better than IPA or methanol, but it still took me a few hours to get the glue off. Next time I'll try freezing it, or find a solvent with a higher concentration of cyclohexane.

author: SeanB
author_rank: Super Contributor
timestamp: December 04, 2016, 06:08:10 am
content: R600 has no smell, and is a very pure propane. Your fridge likely has 18g of it in the refrigeration circuit.

author: BradC
author_rank: Super Contributor
timestamp: December 04, 2016, 11:45:22 am
content: Quote from: SeanB on December 04, 2016, 06:08:10 amR600 is plain old butane. R600a is iso-butane. R290 is propane.Fridges run on R600a, and it's a crapshoot as to whether you get gas with or without the stench. Mercaptan is not particularly friendly for refrigeration systems (although it is in minute quantities and doesn't really hurt anything), but there are odorants out there that will supposedly maintain the smell over time. Some companies do, some don't.Mercaptan is broken down over time by stuff normally found in refrigeration circuits, so often after a year or so the gas generally loses all its smell anyway.

author: gtc
author_rank: Newbie
timestamp: March 28, 2018, 10:53:05 am
content: Old thread, but there's an old remedy: GC Electronics RADIO TV CEMENT SOLVENT:https://www.alliedelec.com/gc-electronics-10-312/70159779/