What is that kit like substance on capacitors? - Page 1
Forum section: electronics / beginners

author: Tonn
author_rank: Contributor
timestamp: January 14, 2017, 10:01:50 pm
content: Hi,Teardown videos by Dave Jones on Youtube show a kit like substance having been applied to electrolytic capacitors of power supplies.He calls it sillicacet(?) and it's applied with a hot glue gun.Could someone please explain to me what that substance is and it's purpose?Thanks.

author: Rerouter
author_rank: Super Contributor
timestamp: January 14, 2017, 10:06:20 pm
content: Dave refers to it as "hot snot" its generally a thermosoftening glue, and in reality very similar to a high temperature hot glue guns hobby stores sell,Its purpose is mechanical support for heavy components, so impacts and vibration do not rip them off the board,

author: Cerebus
author_rank: Super Contributor
timestamp: January 14, 2017, 10:32:13 pm
content: Quote from: Tonn on January 14, 2017, 10:01:50 pmI'm not sure what word you were looking for but I suspect that "kit" isn't it.Silasticis the trade name for a room temperature vulcanizing (RTV) silicone rubber adhesive but gets used as a generic term in the same way that "Hoover" does. It's there to stabilize components that don't have significant or sufficient integral mechanical support from being affected by vibration and the like.Quote

author: Tonn
author_rank: Contributor
timestamp: January 15, 2017, 11:23:31 am
content: Thanks very much,Silastic is exactly what I was looking for.(As for the word kit: I talk to co-workers in four different languages, so I mixed up. The word paste would have been better.)

author: ziplock9000
author_rank: Regular Contributor
timestamp: January 16, 2017, 08:21:08 pm
content: Quote from: Cerebus on January 14, 2017, 10:32:13 pm

author: Tonn
author_rank: Contributor
timestamp: January 18, 2017, 07:52:53 pm
content: Hi Ziplock9000,Would you please share your find with us?

author: ziplock9000
author_rank: Regular Contributor
timestamp: January 19, 2017, 02:29:50 am
content: Quote from: Tonn on January 18, 2017, 07:52:53 pmSure. Just use the waterproofing stuff for bathroom fittings. It's the same stuff, much cheaper and comes in larger volumes.http://www.ebay.co.uk/itm/RTV-Instant-Gasket-Maker-Silicone-Rubber-Adhesive-Sealant-300g-Cartridge-CLEAR-/320910179556?&_trksid=p2056016.m2516.l5255

author: Cerebus
author_rank: Super Contributor
timestamp: January 20, 2017, 12:20:32 am
content: Quote from: ziplock9000 on January 19, 2017, 02:29:50 amBeware that if you use builder's/plumber's silicone youmustget theneutral-cureversion not the more commonacetoxy-cure. The acetoxy-cure version releases acetic acid as it cures which is obviously very bad news on a circuit board. If it doesn't say "neutral cure", assume it isn't.

author: jc101
author_rank: Frequent Contributor
timestamp: January 20, 2017, 01:38:59 pm
content: The stuff I use is Dow Corning 744, which is designed for use on electronics/electrical items.Last time I bought some it came from Rapid and it lasts ages. If you cap the end with a bag or such like between uses (i.e. next day) then just pull the small plug (few mm long) out the end out and you're ready to go. As long as it's a reasonable seal it will be fine.https://www.rapidonline.com/dow-corning-744-silicone-adhesive-white-310ml-87-1228

author: ziplock9000
author_rank: Regular Contributor
timestamp: January 20, 2017, 02:57:50 pm
content: Quote from: jc101 on January 20, 2017, 01:38:59 pm16 quid.. Haway I'm not that fancy!

author: jc101
author_rank: Frequent Contributor
timestamp: January 20, 2017, 07:14:24 pm
content: Quote from: ziplock9000 on January 20, 2017, 02:57:50 pmWell you can get it other places too. I bought my last tube on 7 Jan 2016 and it's still going, just part of a large order from Rapid. It's great stuff designed for the job and doesn't seem to go off by itself like some. I think they do smaller tubes too, depends on how much you need to use.

author: Tonn
author_rank: Contributor
timestamp: January 22, 2017, 12:18:53 am
content: @jc101: Thanks for referencing "Dow Corning 744".There is a 90ml tube on the market and I'll give it a try.

author: SeanB
author_rank: Super Contributor
timestamp: January 22, 2017, 04:54:27 pm
content: Store in a ziploc bad, placed inside some genuine tupperware with a moisture absorbing sachet there as well, and place in the fridge between uses. Lasts a lot longer that way, keeping the silicone away from oxygen and moisture helps it stay usable longer.

author: Tonn
author_rank: Contributor
timestamp: January 26, 2017, 06:24:29 pm
content: @SeanB, thanks very much. I'll do that.