What is that typically white anchoring adhesive used on PCBs? - Page 1
Forum section: electronics / general

author: Winston
author_rank: Regular Contributor
timestamp: February 12, 2017, 12:46:18 am
content: I am referring to that usually white adhesive substance used in commercial/consumer electronics to anchor components to the PCB or to each other to prevent their movement. I'd like to know the brand name of that stuff or a suitable substitute for it because it seems to be able to stick extremely well to anything unlike anything else I've ever seen and I'd like to use it or something like it for component anchoring.

author: ataradov
author_rank: Super Contributor
timestamp: February 12, 2017, 01:06:23 am
content: The trade name is Silastic. Generic name is silicone rubber.

author: iainwhite
author_rank: Unknown
timestamp: February 12, 2017, 01:11:50 am
content: https://www.dowcorning.com/content/electronics/electronicsproducts/adhesives-sealants-overview.aspx

author: nanofrog
author_rank: Super Contributor
timestamp: February 12, 2017, 02:15:59 am
content: GE's Silicone II caulk is readily available, and suitable for electronics use (no acids released during the curing process that would cause corrosion; it uses moisture from the air instead to catalyze the curing process). Easily found in most hardware stores, Wall*Mart, and of course the big DIY box stores such as Home Despot or Blowes.Not expensive either.Although it seems less cost effective, the smaller tubes can actually reduce waste from the standard sized tubes for a caulking gun when it hardens in the nozzle/tip (i.e. 2.8oz tube, which runs ~$4; larger 10.1oz runs ~$6.50).

author: Winston
author_rank: Regular Contributor
timestamp: February 13, 2017, 06:29:12 pm
content: Thanks for the replies. I've seen the white silicone on PCBs, but the stuff I'm thinking about seems to bemuch more rigid and tougherthan silicone would ever cure to become. It's not rubbery at all and, from my attempts to remove it from pulled components, sticks permanently to anything. It seems more like it might be a two-part adhesive, one which doesn't require exposure to air to cure and is therefore not limited by layer thickness as is RTV. It's more like construction adhesives, but I doubt that they're electronics safe. From the ingredients on this example MSDS, I'd say they definitely are not:http://www.gorillatough.com/sites/default/files/Gorilla%20Construction%20Adhesive%20SDS.PDFThe intended use is for (hobbyist) soldered wire anchoring at the PC board. You'll see it used in commercial electronics for exactly that. Flexible silicone would allow flexing which is exactly what I want to avoid. Two part epoxy does not stick to everything like the white electronics adhesive I'm thinking about.

author: elecman14
author_rank: Unknown
timestamp: February 13, 2017, 06:45:53 pm
content: Could it be something like Scotch-Weld DP420-WHITE-400ML?If not Digikey has a really good glue selection that is worth a browse:https://www.digikey.com/products/en/tapes-adhesives/glue-adhesives-applicators/909

author: eKretz
author_rank: Frequent Contributor
timestamp: February 13, 2017, 09:39:40 pm
content: I know the stuff the OP is talking about and it is NOT silicone adhesive. It's some very tenacious stuff whatever it is. I remember it vividly due to it being such a pain in the butt to get loose. It's often used in PC power supplies to secure components, especially taller caps, but also others.It's especially a pain when desoldering through hole components. You can desolder perfectly to the point that the component should fall out but if that stuff is on the components it makes it seem like it's still soldered in tight. You pretty much need to cut along the component with a knife or something to break the stuff loose.