Don't know how I heard about making logs from waste paper but... having seen the various offerings on the 'net for making them I thought "I could MAKE something that does that".
Anyway, I've had a 1st go... It's two box sections made of tongue and groove board made to fit (not too tightly) around a legnth of 3x3 inch (ish) timber off-cut.
Being tongue and groove, one section fits snugly on top of the other for varied lengths of briquette!
The bottom, as you can see, clips on and off for ease briquette removal. The bottom and 1st section have small holes for excess liquid egress.
Once the soaked paper is in the mould, the timber off-cut is inserted as a ram and pressure exerted on it. I put a ratchet strap around the whole shooting match and tighten it but any method will do as long as it has the desired effect!
Here are some images:
