Defending from vibration - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: November 28, 2017, 08:58:50 am
content: I am designing a board and was intending to thinly pot the whole thing in a tray to help hold down things like large capacitors and inductors. But is there a way of doing this with just some sort of glue? Hot melt glue might no be the answer here as it does become soft easily and ambients of 50C are the design norm so it needs to be a bit better than that but as easy to apply. I see a lot of the white stuff on tear-downs linking capacitors together but this is not really an afterthought in this case it's an integral part of a design requirement because the unit will be mounted on a moving vehicle so I don't want capacitors flapping around.

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2017, 09:09:03 am
content: Apartialpotting job is probably what you want.Even a thick conformal coating would do the job.Rework's a bitch.

author: Dubbie
author_rank: Unknown
timestamp: November 28, 2017, 09:11:05 am
content: I think rework is quietly dropping the board into the nearest recycling bin and assembling a new one

author: Simon
author_rank: Unknown
timestamp: November 28, 2017, 09:17:14 am
content: Well what I usually plan is a shallow tray and a thin layer that just anchors the bases down and stops stuff moving, full immersion is certainly not necessary. Something with potting characteristics that can be applied to points and is thick enough to not run would be ideal. there are certainly no prizes for adding weight and components just to stop potting glue from running away.

author: Simon
author_rank: Unknown
timestamp: November 28, 2017, 09:17:43 am
content: Quote from: Dubbie on November 28, 2017, 09:11:05 amPretty much. I don't design for the dump so when it's a gonna it's a gonna.

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2017, 09:31:17 am
content: Your RS should have a product that suits:http://nz.rs-online.com/web/c/adhesives-sealants-tapes/adhesives-glues/potting-compounds/?sra=p

author: Simon
author_rank: Unknown
timestamp: November 28, 2017, 10:02:07 am
content: yes potting compounds are easily obtainable. I have a 100x300mm PCB, I'd rather not even thinly pot the whole thing just to hold down some capacitors.

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2017, 10:06:11 am
content: Quote from: Simon on November 28, 2017, 10:02:07 amThen a better pick might be here:http://nz.rs-online.com/web/c/adhesives-sealants-tapes/adhesives-glues/

author: Simon
author_rank: Unknown
timestamp: November 28, 2017, 10:35:52 am
content: hm yes an epoxy glue seems to be the answer, same job but thicker on application so no need to mould it.

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2017, 07:08:41 pm
content: Quote from: Simon on November 28, 2017, 10:35:52 amPost up the product you decide on or find best....you know, it can help others.

author: SeanB
author_rank: Super Contributor
timestamp: November 28, 2017, 07:47:22 pm
content: Electronics grade silicone adhesive, or even a flexible potting compound, or at a pinch just some polyurethane construction adhesive ( so long as it is not an acetoxy cure, cyanide with the smell of almonds is fine) as a application to hold down will work as well.

author: Simon
author_rank: Unknown
timestamp: November 29, 2017, 08:00:36 am
content: Quote from: tautech on November 28, 2017, 07:08:41 pmWell the plan has changed and i didn't settle on a product by epoxy glues seem plentiful and providing they can work at the required temperature I expect any will do. In this particular case it will be a metal folded tray and a thin layer of potting.

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2017, 08:09:13 am
content: Quote from: Simon on November 29, 2017, 08:00:36 amTake care with products not intended for electronics as their shrinkage/stress factors could bite you in the bum.No way I'd be using just any old epoxy.

author: Simon
author_rank: Unknown
timestamp: November 29, 2017, 08:17:03 am
content: Quote from: tautech on November 29, 2017, 08:09:13 amWell this is why I was asking.