Chinese Blob Adhesive - Page 1
Forum section: electronics / general

author: ehughes
author_rank: Frequent Contributor
timestamp: February 19, 2016, 04:28:17 pm
content: I am trying to figure the best adhesive to use on assemblies for securing patches, etc. You always see the "snot" of consumer electronics. I have used everything from superglue to silicon RTV. I would like to find a product that gets stiff (but not too stiff) and dispenses well.

author: wraper
author_rank: Unknown
timestamp: February 19, 2016, 04:37:16 pm
content: Superglue is a bit conductive, so no good. I find Electronics grade/neutral RTV silicone is among the best for the long term reliability. Of course if you need faster cure time or apply a very thick layer, two component adhesives would be a better choice.

author: station240
author_rank: Unknown
timestamp: February 24, 2016, 01:02:04 am
content: Another to consider is Hot Glue.

author: Ice-Tea
author_rank: Super Contributor
timestamp: February 24, 2016, 08:35:32 am
content: Quote from: station240 on February 24, 2016, 01:02:04 amPlease, dear Lord, no. There's this minor issue with hot melt: it melts when it gets hot. As electronics often do. Once had a batch of Chinese PSUs. If you turned them upside down, the goo would be leaking out

author: AndyC_772
author_rank: Super Contributor
timestamp: February 24, 2016, 08:44:19 am
content: https://www.dowcorning.com/content/electronics/electronicsproducts/adhesives-sealants-overview.aspx

author: wraper
author_rank: Unknown
timestamp: February 24, 2016, 08:56:59 am
content: Quote from: Ice-Tea on February 24, 2016, 08:35:32 amIt is much worse. Even without any melting, it will just fall off after a year or two. If used at low temperatures (doesn't even need to be negative), it can fall off even the same day.

author: Ice-Tea
author_rank: Super Contributor
timestamp: February 24, 2016, 09:13:14 am
content: Yeah, using hotmelt on electronics is like a large neon sign saying "yeah, I don't have a clue".

author: m98
author_rank: Frequent Contributor
timestamp: February 24, 2016, 12:14:01 pm
content: If vibration isn't a problem: Rotabond 2000If it is: 2K Epoxy

author: elecman14
author_rank: Unknown
timestamp: February 24, 2016, 07:02:39 pm
content: Not all hot melt is created equal. I have used 3M Scotch-Weld 1099 in the past with lots of luck. The way it was explained to me, when the glue is heated it actually changes chemical structure and consistency. This is different from the glue stick hot glue referenced above. Since I am not a chemist you may want to verify that. But I would recommend looking into that glue...

author: station240
author_rank: Unknown
timestamp: February 24, 2016, 08:03:32 pm
content: Quote from: Ice-Tea on February 24, 2016, 08:35:32 amThat chinese electronics is capable of melting glue doesn't surprise me. Your problem is you ordered shoddy junk that runs hot, not so much the glue.I haveneverencountered anything where the glue has melted, hot glue or other.@elecman14 Thanks for proving an example of a meltable glue that is suitable.I do recall there is some decent glue available in stick form, obviously not the sort of junk you get from hardware stores.Also the wikipedia article on hotmelt has way more information, eg use of low-temperature and high-temperature guns/glue, special industrial glue/guns, different materials.

author: Ice-Tea
author_rank: Super Contributor
timestamp: February 25, 2016, 05:48:45 am
content: Quote from: station240 on February 24, 2016, 08:03:32 pmNot to imply that these units were not shoddy junk (because they were) but I have to disagree. Regular hotmelt starts going south at about 100°C. I have no issue with a PSU, under load and high ambient, that has stuff running at that temp.QuoteYou haven't, I have. As others indicated, not all hotglue is created equal and I'm sure some of that stuff is suitable. The regular stuff, however, is not. At least you have to put in quite a bit more effort beyond "let's head to the HW store and get a cheap box of glue sticks". And if you put in additional effort, you might as well do things righ and get epoxy or PU adhesive or whatever.

author: RobertBG
author_rank: Regular Contributor
timestamp: February 25, 2016, 06:10:56 pm
content: Quote from: Ice-Tea on February 24, 2016, 09:13:14 amHot snot has been used in the industry for yearsSeriously folks if you're using dollar store glue sticks then maybe this statement applies to you but there's plenty of suitable hot melt glues that work well.Lastly if you are trying to pot something that gets hot enough to melt a high temp hot melt glue you might want to rethink what you're doing for a minuteI generally use the 3M Scotch Weld 3748VO as it is pretty much the go to in the electronics industry and is available in different temps but chances are you can get away with a cheaper version if you dont need certain properties.I've found it has reliably replaced my need for epoxies 98% of the time so it is cost effective for me.We do have some other glues we'll use but I tend to keep them off the line in case someone grabs the wrong one for the job.Take a look herehttps://www.hotmelt.com/products/3m-scotch-weld-3748vo-electronics-hot-meltalthough sad to say they dont offer a neon sign like the other poster suggestedAlso if the price tag scares you chances are they have a cheaper polymide that will work for you at a much lower price.They are pretty stable up to 150C,just be sure to ask if it will cause issues with copper as some do,hence why I stick with the 3M.

author: LordHexahedron
author_rank: Contributor
timestamp: March 07, 2016, 12:26:57 am
content: Quote from: Ice-Tea on February 25, 2016, 05:48:45 amYou haven't, I have. As others indicated, not all hotglue is created equal and I'm sure some of that stuff is suitable. The regular stuff, however, is not. At least you have to put in quite a bit more effort beyond "let's head to the HW store and get a cheap box of glue sticks". And if you put in additional effort, you might as well do things righ and get epoxy or PU adhesive or whatever.I'm not even sure why you'd use hotglue anyway, I could run down to the dollar store and pick up a rather large supply of epoxy (not the best epoxy, but it's actually not that bad either) for a couple bucks.I mean, hotglue cures quickly - fine, I can see it being an ok thing to do while waiting for the epoxy to cure (you know, so whatever you're gluing doesn't move around) but that's about it - I can't imagine why you'd use it for electronics as it's neither particularly strong nor heat resistant (which is desirable in electronics)