Heather T of Make A Bag asked "could you find a link for the fuel bricks so we can find out more about them?"
It came from the Centre for Alternative Technology. You tear up paper (I'm sure you could also use card) and soak it with water in a bucket for a few hours. Then you slop it into the brickmaker and press on the levers which squeeze most of the water out. It's sturdily made, and I stood on it for maximum squeeze. It felt very solid. I wasn't at all worried it would bend or break.
The "logs" that you make seem to hold together very well. It's amazing how a soggy mass of papiermache turns into something that's definitely a brick. They do come out somewhat wet though , and need to be dried before burning. I don't know yet how long that takes, but it probably depends on the conditions you store them in. And I don't know how you can be sure when they are dry all the way through.
The leaflet that comes with the machine says that one broadsheet newspaper makes a briquette that burns for about an hour. I haven't tried it yet - my briquettes are still drying. I also don't know how easy they are to set alight in the first place.
One thing I can say is that they're easy to make, although tearing up all that paper can be a bit tedious. I'll probably use my shredder next time I do it, but the family were watching Boxing Day TV and I didn't want to run a noisy device. Making the actual bricks is dead easy and quick. I've made three already, and I've only got through about half of all the Christmas wrapping paper, and I haven't even started on all the cardboard boxes.
I'll let you know when I've tested them out, and tell you how well they burned. It seems like a good thing - a human-powered gadget to turn waste paper and card into home-heating fuel. Maybe one day we'll own half an acre of coppiced woodland, and we'll chop our own wood for heating. But until then recycled briquettes may be a good option.