Thoughts on conductive paint?

Thread Starter

Jonlate

Joined Dec 21, 2017
75
Has anyone made a complete circuit board using conductive paint or pen?

I want to make up a small circuit and rather than linking bits with solder joins or wire, would thus do the trick instead?

Any thoughts on this stuff?
 

crutschow

Joined Mar 14, 2008
23,141
I found a reference that stated "the Bare Conductive ink has a resistance of 55 ohms per square whereas an equivalent copper trace has an approximate resistance of about 0.3 milliohms per square" so that needs to be considered for any traces connected to a low impedance or must carry any significant current.
You would multiply the length of the trace divided by its width times 55Ω to get the trace resistance.
 

jpanhalt

Joined Jan 18, 2008
7,691
You could use a silver nanoparticle ink. They have been around since about 2012.

One of the original papers: https://news.illinois.edu/view/6367/205162
A more recent paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4714735/

Commercial preparations are available but are not cheap. Search on "silver nanoparticle ink."

Aldrich-Sigma is one source (don't let the price scare you):
https://www.sigmaaldrich.com/catalog/product/aldrich/798738?lang=en&region=US&gclid=EAIaIQobChMIxZu3lMC62QIVhkwNCh16SQGbEAAYASAAEgIa6PD_BwE
https://www.sigmaaldrich.com/catalog/product/aldrich/796042?lang=en&region=US

Among the advantages:
1) Very low electrical resistance. Some rival silver wire.
2) Flexible
3) Can actually be printed with commercial ink jet printers.
4) Reportedly can be soldered to.

For personal, non-commercial use, you can make your own much cheaper. A complete description is given in the JACS article with the same authors as in my first link. The reaction is a modified Tollen's reaction (see: Wikipedia) that has been used to silver plate telescope mirrors for many years.

Edit: I have also heard of people using the conductive paint used for repairing defroster wires on auto glass.
 
Last edited:

AlbertHall

Joined Jun 4, 2014
8,184
I bought some 'conductive glue' but it really failed both those descriptions. It was about 470Ω between the two glued parts and great care was necessary as the two parts were easily pulled apart.
 

Thread Starter

Jonlate

Joined Dec 21, 2017
75
Thanks for answers.
I think I will go with wire and trim it short to keep it tidy.
I have never made a pcb and printing one out and etching one seems to hard for me to do, and requires lots of extra stuff.
 
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