I tried making a homemade solenoid. It's not working. I'm using 12V battery (2x 6V), a plastic pen tube with a nail for the core, and thick steel wire tightly wrapped around the pen tube. I think perhaps the wire is too thick or needs to be insulated?. ..and should i try and find a metal tube instead of plastic?
Plastic tube is perfectly fine, but you need enamelled copper wire (see: **broken link removed** ), and quite a lot of it, to build a solenoid that will show you some action being fed of 12V battery ..