WARNING: Ammonia solutions have a strong smell, silver salts tend to stain and formic acid is corrosive. Gloves should be worn and this experiment should be performed outside or in a fume hood. Greetings fellow nerds. In this video we’re going to make conductive silver ink. But first I need to crush your expectations. This is not cheaper or better than commercially available conductive inks. Our objective here is to explore the science. First we take 1g of silver acetate and put in a magnetic stir bar. Then we add 2.5mL of concentrated ammonia solution. The solution is stirred for several minutes until all the silver acetate is completely dissolved. What’s happening here is the ammonia is reacting with the silver acetate to form diamminesilver acetate. When it’s clear we then slowly add 0.2mL of formic acid drop by drop. What’s happening is the formic acid is reacting with the excess ammonia to form ammonium formate. Later we will use it to reduce the silver into metal but a bit of it reacts prematurely to produce silver particles seen here. When all the formic acid is added and thoroughly stirred, the solution is capped and allowed to react overnight. Here we are the next day. There are some unwanted silver particles in the ink. I recommend removing the particles by filtering the solution through a syringe filter with 0.2 micrometer pores. This is very important for those of you who will be using this in an inkjet printer to print circuit boards since the particles might clog your inkjet printer head if not removed. And there we have it clear, particle free ink. Now to test it. Here we have a bare circuit board without any copper on it. Now we just simply apply some ink. I have crappy art ability which explains why I’m a chemist but you get the idea. I recommend using a modded inkjet printer or a 3D printer that’s been programmed to print a single layer. Anyway once you’ve drawn a pattern let it dry. What’s happening here is the ammonia is evaporating and the formic acid reacts with the silver ions to form elemental silver that precipitates out. When most of it has reacted the board is then heated to one hundred celsius and the particles of silver are sintered together to form a highly conductive bond. Some of you may be asking if this can be done on paper. Unfortunately this particular type of conductive ink does not work well with paper and just turns to silver black. I recommend using a particle based conductive ink rather than a complex ion based ink like this one. Anyway, let’s test its conductivity. Here I am with an ohmmeter and there it is. A relatively low resistance for a conductive ink. So there we have it, particle free conductive silver ink. Thanks for watching. The inspiration for this video came from this article. In this video we’ll be making silver mirrors In this video we’re going to make silver acetate.