Works quite well. I've made (and burned) several dozen briquettes now with this device. It has lasted ok, though I found that I can push the sieve through the bottom if I put my entire weight on it... Standing on a board on the handles. Y'know to get the last of the water out. I may have to go heavy duty.
Some observations.
* 2 hours burning time? A bit optimistic. 1 hour is more realistic.
* Little ash? Meh, most paper produces a lot of ash compared to wood.
* Minimum of a week, more like 2-3 weeks to dry the briquettes.
* They glow red, not bright orange. Wood *is* better. Wood is higher density than the briquettes this device can produce though.
I've been experimenting with different techniques for briquette production.
1. Shredding. I'm not convinced this is a good idea. Think about how we want it to burn. From the outside in. If you shred the paper it leaves many air gaps into the briquette. I've found that shredded paper briquettes tend to burn for a short time on the outside, then the flame goes into the centre of the briquette and you get smouldering instead.
2. Soaking time. Minimum of 3 days. A week is more like it. You unfortunately also get bacterial growth and strange smells though if you leave it longer.
3. Bleach. Does appear to help break up the paper fibres and produce a pulp. Also kills bacteria.
4. Use a wooden board on top of the handles to press down. Saves the hands.
5. Pulping the paper. So far I have found that the better briquettes were produced by destroying the paper structure entirely, so it's turned into a pulp. e.g. soaked for a week, with bleach, then use a hand drill & whisking implement to turn the paper back into pulp in the bucket. Good fun but *very* messy though, paper spattered everywhere.
Really we're after a briquette with similar density to wood. i.e. heavy (when dry). I don't think this device can produce enough pressure to force the paper fibres that close together, there's still a lot of air in there when dry. You would need a longer lever and a smaller piston surface to produce much higher pressures.
note a lot of paper, particularly the shiny stuff is already treated with fire retardants, i.e. if you use it in a briquette, it won't burn well (you'll see a weak green flame and smouldering rather than burning).
Oh, it's also worth noting that paper briquettes are also fairly good insulation material under dry conditions. Flamable yes, though the addition of borax can act as a fire retardant and anti-fungal.