Electrical potting compound. Gel or putty? Mixing dispenser guns?

[Grant Gunderson]

I need to pot a bunch of electrical connectors in the devise. Can’t easily make a dam around them. So looking for ideally a putty or a thick 2 part epoxy style gel. Any recommendations? I think dispensing gun with mixing tips would be ideal. I’ll do 3-4 a day. So will bedf a fresh tip for each one I do as they will be a few hours apart.

 

[djbmw]

I need to pot a bunch of electrical connectors in the devise. Can’t easily make a dam around them. So looking for ideally a putty or a thick 2 part epoxy style gel. Any recommendations? I think dispensing gun with mixing tips would be ideal. I’ll do 3-4 a day. So will bedf a fresh tip for each one I do as they will be a few hours apart.

I've only ever used a two part potting epoxy. Generally you want it quite liquid to fully encapsulate the compoments without trapping air. I would imagine an epoxy putty could trap air and/or not fully encase compoments. Personally, I would try to make a dam, angle the device, or try some way to use standard 2 part potting epoxy.

 

[Grant Gunderson]

I've only ever used a two part potting epoxy. Generally you want it quite liquid to fully encapsulate the compoments without trapping air. I would imagine an epoxy putty could trap air and/or not fully encase compoments. Personally, I would try to make a dam, angle the device, or try some way to use standard 2 part potting epoxy.

Thanks I’m trying to solve the issue of power pins vibrating loose in a propitiatory connector that would require a lot of work to remove so ideally I pot it in place. A thicker UV cure option might work too.

 

[no704]

Hot glue?

 

[Beerhippie]

Hot glue?

Seems like that's what's used for this purpose in a lot of electronics. "Potting" is for environmental protection--or to insure I can't work on it.

 

[djbmw]

Thanks I’m trying to solve the issue of power pins vibrating loose in a propitiatory connector that would require a lot of work to remove so ideally I pot it in place. A thicker UV cure option might work too.

Generally power connectors (like USB-C) will have legs that are soldered into board thru-holes. This provides the rigidity needed to ensure longevity with repeated use and vibration.

Do you have feet on your proprietary power connector, and thru-holes on the board to solder it to? How big is the connector? Is it meant to be interfaced by people using the connector often?... or does it remain dormant inside this unit?

 

[Rinspeed]

Electrical grade RTV would work much better than hot glue. RTV162 is what we use at the shop and its good stuff, a little pricey but good stuff.

 

[LXCam]

I’ve done a lot of potting thru the years but always used a two part liquid. Without a full encapsulation I don’t know of anything else out there. Have you considered just using Dow Corning 732 silicon Grant. Thats some pretty serious forever stuff.

 

[PCustoms]

Electric safe rtv or epoxy (usually UV cure these days) is all I deal with on PCBA

 

[AdAstra]

Got some photos or dimensions?

Hot melt glue (polyolefin or nicer polyamide) could be a good option if the other parts can handle the heat. With glue stick dispensing there will be no wasted mixer/dispenser tips.

Most one-part curing adhesives like Silicone RTVs or polyurethane sealants are generally moisture curing (react with water in the air) so may have issues or take a long time to cure deeper than ballpark 3-4 mm from the nearest air surface.

So if it's more than that you're looking at 2 part epoxy (don't use 2 part polyurethane for your application, it goes bad very quickly once opened unless stored perfectly). which is def fussier than 1 part adhesives, or hot melts.

If you're within 3-4 mm, you could try a one-component polyurethane like 3M 5200FC. It'll have similar properties to the Silicone RTVs mentioned above for your purposes, but be way cheaper. If you use a silicone, make sure it's "neutral curing" and not "acid curing", since that can corrode things.

I'd start with hot melts, you probably already have a glue gun.

 

[T444e]

Devcon Epoxy Plus 25 is listed as a potting epoxy. I used it a few weeks ago to seal infill a bulkhead fitting into a cooler. It is definitely a thick epoxy. A dispenser with nozzle is needed, which is why I chose this product. It would have been cumbersome to use the typical 2-part epoxy from a box store. Granger, McMaster-Carr and Zoro sell the Devcon. I procured the Devcon from Zoro and the dispenser and nuzzles from McMaster-Carr, most cost effective.

 

[Zimbo]

Caterpillar calls for potting in some electrical connectors subjected to vibrations see attached