This week I have been demolishing my baren to see how it works. It was a bit nerve-wracking as I have always been fond of this little object and as you can see, I've used it for a lot of my prints.
I was shocked to find that inside, rather than the expected coil of twine, there was just a cardboard pad with crosses punched into it.
I thought 'I can do better than that'. After lots of experimenting with materials, different kinds of twine and testing and re-testing I've come up with a baren that I'd give an 7.5/10 to, pending testing to destruction.
If you want to make your own baren...
The twine needs to be HARD to provide multiple points of contact
The pad needs to be light and slightly convex
The covering needs to be slippy but tough
I am currently investigating using locally grown plants rather than the imported bamboo.