Can I use the same goop to anchor capacitors and waterproof coax+outdoor boxes? - Page 1
Forum section: electronics / beginners

author: cdev
author_rank: Super Contributor
timestamp: December 08, 2018, 10:07:45 pm
content: The title says it all. I would like to re-cap some electronics as well as waterproof some things that will go outdoors. Is there a quality product (I'm assuming some silicone something?) that can do both of the below and also which can have the unused remainder stored without hardening up for some time.1.) Capacitor anchor-goop function.I'd like to find some (silicone rubber?) product that hardens hard enough to grip capacitors and protect them from shaking their booty off of the board. So they don't just have to hang by their solder connections alone, It should act a bit like hot glue, dampening vibration, but also be possible to peel off when its time to replace them. And which doesn't damage or eat through the boards in any way.2.) Waterproofing functionIf appropriate () I also would love to be able to use this same stuff to keep water out of (metal or plastic) boxes which may go outdoors, say on an antenna mast. (will likely leave a small weep-hole at the bottom.) And maybe use it on coax (is this the best thing to use?) which goe outdoors. To keep out the water from rain, snow etc, out. Over many years, hopefully (Or should I use something else?)

author: t1d
author_rank: Super Contributor
timestamp: December 08, 2018, 11:04:23 pm
content: Well, I understand the economy of having only one product, but I don't know of a do-all.There are dedicated glues for securing breadboard components, but they might prove expensive. So, do a search for substitutes... There should be various threads, on the subject, on this forum. "Shoo Goo" is pretty tough stuff, but I don't know that it would be acceptable.Hot glue is not acceptable to use on a PCB, because any heat will soften it.Look at the marine stores for substitute waterproof sealing/gluing/caulk products. Remember to get something with a UV rating, for your outdoor uses. Otherwise, it will die shortly.Keeping the tip sealed and storing the stuff in the refrig will help with the product life, but you just aren't going to be able to keep any of it forever, once it has been opened. A smaller quantity is more expensive per unit, but may save you money by having less die/waste.

author: Ian.M
author_rank: Super Contributor
timestamp: December 09, 2018, 12:12:12 am
content: The only products that I am aware of that can be used both for securing components and for weatherproofing are neutral cure silicone rubbers. They are moisture activated and have a notoriously short tube life once opened as they tend to cure in the tube. They are also very unreliable, as they only adhere well long term to a chemically clean surface (and their curing by-products contaminate surfaces so reapplying them is a bitch), on copper alloys the poorly adherent oxide layer tends to promote bond failure, and if used as a gasket for weather sealing, there must be enough joint area and thickness, and the joint must be compressed after the silicone has fully cured otherwise there is a tendency for the silicone to joint surface bond to fail, forming a micro-crack which will wick water in by capillary action. OTOH if you get the surface preparation and application just right they are highly adherent, so if you need to remove them for rework, you risk hours of scraping with an xacto knife!IMHO Silicones are the 'WD40' of the adhesive/sealant world and are generally more trouble than they are worth, so I only use them for applications where there is no other sealant that's chemically compatible with the materials involved.

author: cdev
author_rank: Super Contributor
timestamp: December 09, 2018, 05:25:01 pm
content: Ian, what would you use for preventing large heavy-ish electrolytic capacitors from moving around? (I just don't want them to "knock" possibly putting extra stress on their leads, in an older unit that may get warm inside sometimes.)Not super hot, hopefully, just warm. 85 C even seems very unlikely. (Some parts nearby may get hotter though, although again, not super likely to happen frequently).This particular unit, a power supply, is convection-cooled. I suppose I could put something in there between them. (I have some shims of corrugated cardboard in there now)Or maybe I should try using double sided foam tape to anchor them together

author: Jwillis
author_rank: Super Contributor
timestamp: December 10, 2018, 12:12:54 am
content: Not sure if people would agree .I use a hot glue gun but only if I know that there isn't going to be a lot of heat created on the board or in the enclosure .And I don't use to much as that can cause a heat problem as well.Also, Hot glue is flammable so again don't use in high temperature areas.For other stuff I use a high temp silicon Like Permatex Black or Ultra Black .It has a continuous temperature resistance of 260C or 400F and stays pliable . But probably won't have the thermal conductivity needed for encasing.

author: cdev
author_rank: Super Contributor
timestamp: December 10, 2018, 12:38:05 am
content: I'll look into that. I just want to prevent the capacitors from being loose, while held on just by their leads. Several caps are virtually touching. So a little dab between them to prevent them knocking and a small dab on the bottom is likely enough.