Looking for glue to keep capacitors on the PCB - Page 1
Forum section: electronics / general

author: qno
author_rank: Frequent Contributor
timestamp: January 19, 2012, 07:22:59 pm
content: Hi all,Does anyone know the type of glue PCB manufactures use to glue big components to the PC board?It is the white stuff you see on capacitors of SMPS's to prevent them from breaking off the board due to vibration.I am looking for glue that does not contain any silicone.A brand name would be helpful.The IPC approved stuff would be best.ThanksQno

author: mariush
author_rank: Super Contributor
timestamp: January 19, 2012, 07:48:33 pm
content: Did you check :http://search.digikey.com/us/en/cat/tapes-adhesives/glue-adhesives-applicators/3867511?k=glue?

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: January 20, 2012, 10:49:05 am
content: Im using thermal glue from DX, quit happy. I dont know what is the original flexible stuff

author: Blue
author_rank: Regular Contributor
timestamp: January 21, 2012, 04:06:51 am
content: What is the problem with silicone?

author: metalphreak
author_rank: Frequent Contributor
timestamp: January 21, 2012, 05:21:40 am
content: Isn't it just some of that potting compound stuff?

author: nanofrog
author_rank: Super Contributor
timestamp: January 21, 2012, 04:10:49 pm
content: Why not just use a hot-melt glue?If you want a name-brand used in the electronics industry, 3M makes a few different formulations that would work for gluing electrolytics. It's quick to use and is inexpensive as well.

author: qno
author_rank: Frequent Contributor
timestamp: January 21, 2012, 08:30:29 pm
content: The silicone will have a devastating effect on some components on the PCB.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: January 21, 2012, 09:22:11 pm
content: There is a special non-acid curing silicone that is designed for this purpose. I remember using some about 20 years back on power supply caps for a SMPS design. Most silicones give off acetic acid as they cure, which is not desireable on circuit boards.

author: Blue
author_rank: Regular Contributor
timestamp: January 25, 2012, 03:30:49 am
content: Acetic acid upon curing. Thats a 1 component pdms only - It reacts with moisture from the air.But you can use e.g. Sylgard 184. It is also a PDMS but two components. One contains a platinum catalyst. Mix 1 part A with 1 part B. Then you have no problem.There are also other components around. Browse though the 3M and Dupont website.

author: G7PSK
author_rank: Super Contributor
timestamp: February 21, 2012, 09:49:50 pm
content: I use 3M double sided acrylic tape. Works on components that get shaken by being on diesel engines, typical peel strength on 10mm is 35 to 40 N. Used by Boeing and commercial vehicle manufacturers for structural bonding.

author: andersendr
author_rank: Regular Contributor
timestamp: February 22, 2012, 04:53:53 am
content: Can't regular hot glue like from an arts and crafts store work? That would be my first choice, it cures by cooling and a plus is no chemicals.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: February 22, 2012, 05:09:26 am
content: Quote from: andersendr on February 22, 2012, 04:53:53 amGenerally not. It can become quite brittle over time and does not adhere all that well to some solder masks. Also, being thermoplastic, it can melt if things get too hot.

author: amspire
author_rank: Super Contributor
timestamp: February 22, 2012, 05:34:33 am
content: I have heard the theory that the acetic acid in silicon sealant can damage components, but I have never seen it. I have used it a number of times when it is all I have at hand and have never had a problem.Has anyone actually had a case where acetic acid based silicon sealant has caused some noticeable corrosion or part damage? Just wondering.Richard.

author: SgtRock
author_rank: Unknown
timestamp: February 22, 2012, 06:18:24 am
content: Dear Qno:--I have had good luck with "Electronic Grade Silicone" (see first 3 below pictures). What I like about this Silicone is that you can fight your way past it if need be. For permanent (and I mean permanent) repairs I use JB Weld. JB Weld is certified non-conductive and has good temperature characteristics. I fixed a friends Computer Speaker System with JB Weld (see last 2 pictures). The PCB kept getting pushed into the box by the plugs, after the "Wun Hung Lo" goop failed, so I permanently fixed it. I was such a cheap unit, that it will likely be cheaper to by a new one, when it finally fails electronically. Dave Jones does use Hot Melt Glue (which he calls "Hot Snot" Ha!") for some jobs like his LED hack of the Hakko 88."Does not squirrel crack nuts on bough of oak tree."Lao Fu 1410 1620Best RegardsClear Ether

author: codeboy2k
author_rank: Super Contributor
timestamp: February 27, 2012, 10:47:21 pm
content: Quote from: qno on January 19, 2012, 07:22:59 pmI don't know what they actually use, but it looks and feels like Mastic, also called thinset, for setting ceramic tiles.Mastic is cheap, it flows slightly, you can squeeze it out from a tube using compressed air, so I can see this stuffbeing used in a "cost conscious" assembly house in China for making all those SMPSs

author: andyg
author_rank: Regular Contributor
timestamp: March 07, 2012, 03:26:56 pm
content: Quote from: qno on January 19, 2012, 07:22:59 pmCheck out Masterbond epoxy systems.http://www.masterbond.com/products/epoxy-systemsThey probably have what you're after. I don't know if they are IPC approved or not but I have seen it used in military/aerospace PCBs for this purpose.

author: G7PSK
author_rank: Super Contributor
timestamp: March 10, 2012, 11:01:07 pm
content: Quote from: amspire on February 22, 2012, 05:34:33 amI once made the mistake of encapsulating some electronics that were going under the bonnet of a land rover with bathroom silicone sealant. The wiring went green within 12 hours it took about a year for the electronics to completely fail and it was impossible to clear all the silicone from the board to make a repair, so I had to totally remake the board.