Silicon: conductive?

[reverendmaynard]

I'm putting together a vho canopy and was considering using silicon to seal the backside of the end caps where the screws and wires go in. Do I have to worry about getting silicon on the contacts and causing a short?

 

[rsteagall]

Yes....maybe....

I used silicone once on an electronic project in school. It was fine at first, but over time conductive properties started to occur and my project shorted out. This was dealing with a very low voltage application though. I was dealing with 0vdc - 5vdc and adc controlers. In high voltage applications, I don't know how conductive it would be.

 

[goby1]

Silicone is a polymer chain with Si instead of C as the backbone atom. It is a decent insulator in its pure form, but variants in the chemistry (side atoms and functional end groups) can make it somewhat conductive. I would guess that this is especially true for silicones designed to be good thermal conductors. It might be messy, but vaseline would work as a contact insulator. I'd be weary of the acetic acid usually used in conventional silicone adhesives. If the silicone won't touch the contacts then it would work very well to keep water out, if that's what you are interested in.

G1

 

[Highlander]

Re: Silicon: conductive?

Silicon: conductive?

Semi

 

[reverendmaynard]

<a href=showthread.php?s=&postid=6657984#post6657984 target=_blank>Originally posted</a> by goby1
Silicone is a polymer chain with Si instead of C as the backbone atom. It is a decent insulator in its pure form, but variants in the chemistry (side atoms and functional end groups) can make it somewhat conductive. I would guess that this is especially true for silicones designed to be good thermal conductors. It might be messy, but vaseline would work as a contact insulator. I'd be weary of the acetic acid usually used in conventional silicone adhesives. If the silicone won't touch the contacts then it would work very well to keep water out, if that's what you are interested in.

G1

So perhaps some vaseline down deep in the holes where the contacts and wires meet, with a layer of silicon on top of that would work?

 

[BeanAnimal]

Use epoxy

 

[goby1]

But then you won't be able to take the wires out..

Elemental silicon, not silicone, is a semiconductor...

Why do you want to seal the backs? Any what part specifically are you talking about sealing?

G1

 

[RicksReefs]

when i made my first PVC endcaps, I filled them full of silicone to seal them up. the bulb ends were in a bed of silicone and they worked fine for 2 years, even with the bulbs being overdriven 4X.

 

[reverendmaynard]

Thanks for your help folks. I've already assembled it. I didn't put anything inside the end caps because they had gaskets that went between the bottom of the end cap and the reflector. I sealed the top side of the reflector with silicone. I'll post some pics shortly.

With or without silcone, taking the wires out of the endcaps is quite difficult. They slide in easily, but the contacts inside must be angled in such a way that they grab the wire and prevent it from coming out.

 

[Paul B]

You can use silicone with no problem, As an electrician I use it all the time on outdoor connections but if you are not comfortable with that they make a product called "liquid electrical tape" which is made for what you want. You can get it in a electrical, automotive or marine store. (it's probably made out of silicone though).
Paul

 

[BeanAnimal]

Paul, I have used boxes full of the silicone filled wire nuts and shrink tubes. Good stuff!