Conductive paint for shielding... tips, hints, expected resistance...

[Leandro Muñoz]

Hi, I'm on last steps of my first guitar, and am on the shielding process with a pint of the stewmac's conductive paint.
I just have been applying some 3 layers to some parts and I'm really wondering if some 30 to 50 ohms is ok.... I also heard about applying with some slow-little stroke technique but I guess...

What would you recommend? how do I know I'm.... there?

thank you in advance

[David King]

Your 50 ohms is just fine for a graphite/carbon conductive paint.

[Art Davila]

Can you use copper paint?

[David King]

Art,
Are you asking about a specific paint? I don't think copper anti-fouling paints are quite conductive but copperleaf would be fine. There are silver plated copper conductive paints that are excellent. I used to use one from Spraylat corp but at $500 a gallon (and probably more now) it wasn't very practical because it only had a 6 month shelf life. I've since gone to rattle can paint because that will keep for years if you can keep the tip clear.

[Art Davila]

I saw a conductive copper paint a while ago and always thought I would give it a try, for no other reason than I thought it would look nicer than the black stuff.
I have used the copper foil tape but thought it would be so much easier to paint the cavities. I did not know they don't conduct well, the use I saw was to paint traces to built in speakers then spackle over the paint. I just thought it would conduct well enough.
Glad I never got around to using it.

[David King]

Art,
Any "conductive" paint is going to be conductive and since copper is the second most conductive metal around it will be awesomely conductive at that. I thought you might be asking about boat paint which is also copper but apparently the binders interfere with the conductivity so it doesn't work well. Just be aware the paints out of a can, especially waterbased ones seem to have a very short shelf life. You don't want to buy more than you can use up. You need to look up the paint's specifications to know what the resistance per square is and then figure out how much thickness and width you need to carry the intended amperage without heating up the room at the same time.

[Art Davila]

Ok I will look into thanx. I have to find the product and see if the cost is worth the effort.