There are DIY projects that you should do at your own risk, and then there are DIY projects that you should do at your own risk. This conductive ink concocted by Jordan Bunker falls into the latter category, but it should be relatively straightforward for those who know what they're doing (or those with proper supervision), and it results in a product that's markedly cheaper than existing off-the-shelf alternatives (Jordan spent around $150 for a decent-sized batch). That can then be used for any number of electronics projects, of which you'll have to discern your own degree of danger. Jordan's promising a video soon, but you can find the complete instructions for making your own at the source link below in the meantime.