# Does JB weld conduct electrcity?



## trains are bad

Eh? Or do you have any other ideas for materials? I suppose epoxy, but I happen to have some JB weld right here.


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## Polaris111688

I'm pretty sure that JB weld is non-conductive.


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## nikongod

im not sure about electrical conductivity, but jb weld was at one time THE choice for gluing heat sinks to over clocked computer chips.

 in any event, it is probably best NOT to rely on the jb weld for insulation. if you are bolting parts to a heat sink and gluing them to increase thermal transfer there is no guarantee that the film of glue will be uniform and thick enough to resist the electricity.

 if you are looking to glue stuff to a pcb, then i would test for resistance (i think you can find info about this on the web using the google.) and then let her rip...


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## RedLeader

easy to test with a multimeter....


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## trains are bad

I was actually planning on using it as sort of a potting compound, and I didn't want it to short out the components.


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## Garbz

Quote:


  Originally Posted by *RedLeader* 
_easy to test with a multimeter...._

 

Depends on the application. A multimetre will show a capacitor is opencircuit, despite that when placed in series with our input stages it lets current through. 
 Multimetre only proves that it's non-conductive to low-voltage DC.


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## error401

I'm not sure if JB Weld is conductive or not, but it definitely has metal in it so it's probably not the best thing to use in any case. If it's ferrous it could interfere with inductors and transformers in the circuit and could have other implications as well, such as increasing parasitic inductance of traces/wires running near it. Probably better to use some standard epoxy resin. There's not really any easy conclusive way I can think of to test that it's not conductive. Resistance is a decent test, but as was mentioned it could have some (even a fair bit if it's composed of metal particles in epoxy) capacitance that may pass high frequency current.

 Edit: Jeeze, responded in the wrong thread...


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## nikongod

Quote:


  Originally Posted by *trains are bad* 
_I was actually planning on using it as sort of a potting compound, and I didn't want it to short out the components._

 

i would think using something which "flows" better before it solidifies would be ideal.

 unless you are just potting a hand-wound ferite bead.... or something like that.


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## dbfreak

JB Weld is NOT conductive.

 Taken from JB Weld's Website under FAQ's:

 Q: Will J-B Weld conduct electricity?
 A: No. J-B Weld is not considered to be a conductor. It is an insulator.


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## elmer_dudd

i guess you could use jb-weld, but wouldn't you want something prettier-- and, like, clear


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## tomb

Quote:


  Originally Posted by *dbfreak* 
_JB Weld is NOT conductive.

 Taken from JB Weld's Website under FAQ's:

 Q: Will J-B Weld conduct electricity?
 A: No. J-B Weld is not considered to be a conductor. It is an insulator._

 

I don't know that I'd take an informal assertion in response to a generalized question, even if it was the mfr. It may be an "insulator" from a laymen's point of view, but that doesn't mean it's appropriate in technical circuitry, or that it doesn't possess magnetic properties that could have serious consequences when used as a transformer potting compound.

 The MSDS (on the same site as this informal FAQ) for J-B Weld resin says it's 10%-20% _*iron powder *_by weight.

 If you really want to avoid the expensive specific potting compound stuff and use an off-the-shelf general epoxy, use Devcon 5 minute epoxy. I've used it for almost everything for decades. It's dependable and easy to use. Most importantly, they quote a Dielectric Strength - 490 Volts/mil: Devcon 5 Minute Epoxy Technical Data You can be sure that will work.

 I haven't found another mfr yet that quotes a dielectric strength outside of the specific electronic products, which cost a fortune and are probably the same stuff anyway.


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## mono

Quote:


  Originally Posted by *trains are bad* 
_I was actually planning on using it as sort of a potting compound, and I didn't want it to short out the components._

 

I've JBWeld potted things with 110V AC in them, and a transformer which did't cause any problems FWIW. If the value of what you're pottig isn't high, I say go ahead and try it as we don't actually have any evidence that it is conductive or capacitive.


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## error401

Quote:


  Originally Posted by *mono* 
_I've JBWeld potted things with 110V AC in them, and a transformer which did't cause any problems FWIW. If the value of what you're pottig isn't high, I say go ahead and try it as we don't actually have any evidence that it is conductive or capacitive._

 

But it's definitely ferrous, which is a bad thing (tm) when working with magnetics. If it works, great, but it's sort of an irreversible process by design, so you'd better get it right the first time...


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## tomb

Devcon 5 minute epoxy is more plentiful, easier to get, and cheaper than J-B Weld. IMHO, there's no reason to justify the risk - however slight - for using J-B Weld.

 (If you're repairing small engine part castings, that's a different matter. 
	

	
	
		
		

		
		
	


	




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## mono

Quote:


  Originally Posted by *error401* 
_But it's definitely ferrous, which is a bad thing (tm) when working with magnetics. If it works, great, but it's sort of an irreversible process by design, so you'd better get it right the first time..._

 

We haven't established that it's ferrous enough to matter.


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## tomb

From Forcefield, a site all about DIY magnet stuff on forcefieldmagnets.com, there was a discussion about winding rotors for DIY wind turbines(!):
  Quote:


 We talking about the same JB Weld (I use the "quick" type sometimes too) that is for engine block repairing, etc? Blackish gray color when mixed?
 If so--it does have a bit of magnetic properties.
 Just put some in the next coil winding or coil center in the next coil you wind and hold it above a spinning rotor with magnets, etc..
 You can feel the "thumping"/cogging in your hand if you hold the coil above just one rotor very easily.
 It also brought up the voltage from the same coils I had in test--about 20% or so.
 Center was maybe 40% filled and stuff was all through the windings when I wound it. 
 

In truth, I was probably too quick to recommend the Devcon, too. If you look at that data sheet I referenced up there, you'll see the maximum service temperature is 200deg.F. So, that's probably not a good choice, either. I guess the best thing is to buy the expensive stuff that's made for this.


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## elmer_dudd

Quote:


 But it's definitely ferrous, which is a bad thing (tm) when working with magnetics. If it works, great, but it's sort of an irreversible process by design, so you'd better get it right the first time... 
 

that's a good point. i wouldn't even use epoxy unless i'm sure that i would never need to take it apart again.
 isn't there silicon/marine glue/filler meant for this specific purpose?


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## trains are bad

Ok this is what I was actually doing.

 1/8" stereo headphone jack, gutted and trimmed down, with a delicate PC mount condenser microphone element soldered directly to it, and then the whole thing encapsulated in a blob of JB weld (except the jack and face of the mic of course). The goal being a very small microphone. I did it, and it works, but I swear there is white noise now, and there wasn't before. It's possible it was there before and I just didn't notice it, but I have ordered some more mics and will try again.


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## soloz2

I just thought I'd give this a bump. I'm looking for an epoxy to use inside some LODs to keep the wires in place and to keep them from shorting out. I know some people use jb weld... but is there something better or is that 5 min epoxy good enough?


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## rb67

Quote:


  Originally Posted by *soloz2* /img/forum/go_quote.gif 
_I just thought I'd give this a bump. I'm looking for an epoxy to use inside some LODs to keep the wires in place and to keep them from shorting out. I know some people use jb weld... but is there something better or is that 5 min epoxy good enough?_

 

The 5 min epoxy should be fine (the clear stuff right). It's definitely not conductive. As for other compounds, I used green stuff epoxy putty (kneadatite blue and yellow) for mine. It is very easy to work with. You can see my build here


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## mono

The main benefit in a 5 minute epoxy is you only have a few minutes wait-time for it to set, otherwise the requirements aren't particularly demanding of a certain "best" product, the differences could be negligible.

 Better epoxy depends on the properties you need. Clear or colored, flexibility, conductivity, capacitance, resistance to heat, cost, availability, etc. 

 To secure some wires it would seem most of these factors don't apply, you might as well use whatever you have or find easily or cheaply. JDWeld doesn't conduct and while I'm not 100% sure, it's doubtful it is capacitive as it uses larger particles of metal in it, unlike micronized, specifically heat-conductive designer epoxy. Not particles so big they'd short something though, just relatively larger. Regardless, JDWeld is formulated to be a harder, strong epoxy than some and there is no particular need for that to secure wires, unless the color just happened to compliment the environment.

 If it were desirable to be able to remove this substance later, you might not want epoxy. If heat resistance isn't a problem then hot glue, or if only moderate heat resistance is needed, a caulking or other gluelike one-part adhesive though the solvent in it should be compatible with the wire insulation type and other materials it would be applied to.


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