How to make transformer bobbins?

I often need to wind a coil for transformers, solenoids, or chokes, & I typically use craft plywood for the ends and a paper tube for the center, cemented with wood glue, or Cyanoacrylate . Then, I usually give it a coat of varnish or epoxy. I am curious what other people are doing in the way of DIY formers. I've tried various plastics, but all that I have tried have been impossible to glue securely.

For rigidity, I want to try thin pcb materieal, something without copper (obviously), or holes, but don't know what it is called. Is such a thing available? What's the term for PCB material without copper, or holes?

What do you folks do when you need custom formers?

reply »