# Is There an Electrically Conductive Glue (not solder)?



## MedusaOblongata (Oct 19, 2005)

I'm looking for an electrically conductive glue, or something like one. This is for a non-flashlight project and I can't use solder. Specifically I'll be joining mylar (Xmas tinsel) to either brass or steel. I want something better than Al tape.
Any ideas?


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## goldserve (Oct 19, 2005)

I believe I saw silver conductive epoxy. Cheers!


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## tvodrd (Oct 19, 2005)

Search www.mcmaster.com for cat# 7661a11 and clk "catalog page." The stuff ain't cheap!

Larry


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## Rusty Toyota (Oct 20, 2005)

I remember reading of a compound (sliver based) that is like an epoxy and is used as a filler between a scooter motor's block and cool head (an add-on to have more heat sinks). It was geared more toward heat transfer, but should work. But I remember it also being quite expensive.


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## balazer (Oct 20, 2005)

Sort of related, but is there a thermally and electrically conductive grease or paste?


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## balazer (Oct 20, 2005)

Oh, for your eletrically conductive glue, check out the Chemtronics CircuitWorks line.


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## lildave (Oct 21, 2005)

look at the automotive store for repair for the window defroster. its conductive epoxy.


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## HarryN (Oct 21, 2005)

I have tested a number of these - and use some of them. The nomal circuit board repair stuff conducts, but is really just for engineering proto use - no real toughness at all.

The stuff at McMaster Carr is actually a good material. If you want "tough" but one called out as "flexible". It is not flexible like silicon caulk, but flexes just enough to take a bounce. My standard test is a 60 mph pitch at a concrete wall. These are both electrically and thermally conductive.

They do need to be cured in an oven - nominally 250 F. Price was around $ 20 / few grams IIRC.

That brings up one more point - clean both surfaces with a good grade of isopropanol (rubbing alcohol) before bonding, as well as your hands. Finger oil is a contaminant. The difference in bond strength is substantial.


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## rwolff (Oct 21, 2005)

You've got to watch out for the defroster repair stuff, since there are 3 varieties:

- Conductive paint for repairing the traces
- Conductive acrylic for re-attaching the tabs where the wire connects
- Conductive epoxy for re-attaching the tabs where the wire connects

The paint is probably no good for your purposes, and the acrylic adhesive didn't work for me. When my defroster tab separated, I used the epoxy kit available here. It costs about 10 bucks more than the McMaster part listed, but it's 15 grams instead of 2.5, and it's in the form of 2 mini-syringes rather than a "one-shot" pack, so you can mix a bit now and a bit later.

ETA:
Note that the FrostFighter kit recommends heat for curing, but it's optional (needs above 24 degrees Celsius to cure, or 10 minute cure at 66 to 93 degrees Celsius - hair-dryer territory).

As for the thermally *and electrically* conductive grease, one of the older Arctic Silver products (if you can still find them) might do the job. The original AS was electrically conductive, but they've been working on getting rid of the electrical conductivity while keeping the thermal conductivity (I believe they had dealt with that, except for capacitive effects, by the time AS3 was released). Avoid Arctic Alumina like the plague (at least for this purpose) - it's main selling point is that it's *completely* nonconductive electrically, and you want electrical conductivity.


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