Tuesday, 23 October 2012

Paper logs & briquettes – Solid fuel for free ?

Like most households, the amount of paper regularly pushed through our letterbox is astounding.   Every week, we receive reams of local advertising material within what are laughably called 'free newspapers', plus flyers for local take-away food services, insurances, garden clearance, roofing, TV aerials and just about anything else you can think of.

Even the postal service gets in on the act, routinely delivering one or two pieces of junk for every real letter which is actually addressed to us.

The addressed mail we receive, from bills to further targeted marketing guff, also eventually needs to be disposed of – anything that has our names or address on it gets shredded as a matter of course.   The remainder of the junk paper is all just dumped in our blue recycling bin and collected by the council every fortnight.

At least until recently.....

We have an open fire in our living room, fronted by an Edwardian cast-iron insert with a mahogany surround that we bought very cheaply on eBay when we were renovating the house.  We replaced the old cracked picture tiles with new picture sets of the wife's choosing, gave the iron frame a good wire brushing and a fresh coat of high-temperature paint, extended the depth of the fireback with some thick steel sideplates and then installed it.  The fireplace in the chimney breast had been blocked up years ago but we opened it up again, enlarged it and brought this great feature back to life.

the fireplace....

We're lucky enough to live in an area which is outside of the urban smoke control zones, and so we can burn wood and coal etc in an open fire.  If you're within a smoke control zone, then you can only burn these materials in an 'approved appliance', usually an enclosed wood burner or similar.

Anyway, back to the story.... 

We buy coal in 25 kg sacks (currently £5.80 each) from a local merchant and we've literally a shed-load of logs from an ash tree bough that broke in high winds last year, and also from the trunks and branches of our own hedge and tree removals.

Last month, I was searching on eBay for an old & cheap hydraulic press for the workshop, and one of the items on offer that struck me was a hydraulic paper-briquetting machine.  This started me thinking, and so I then searched specifically for those manual cross-handled presses I'd seen years ago.  Still plenty of companies selling them, but the cheapest on offer was around £13 delivered and I'd no idea what the build quality would be like – from the photos, they don't appear to very substantial and might damage easily.

Now, you might think £13 is not a lot of money, but in this context it's very significant.  I could buy 56 kg of coal for that money, and even burning all the paper logs we could realistically make in a year probably wouldn't produce the same heat output as that mass of coal.  Coal is a fabulous fuel with a high calorific value and it burns very hot – it's little wonder that Britain's prosperity was built on it.

Still, even low-grade fuel from waste paper is a tempting prospect if it's completely free – we don't even have to go out to collect the waste paper, it gets delivered to the door !    So we just needed to work around the requirement to buy a machine to compress it...

So, here's a couple of ways we came up with to make the logs, just using things we already had to hand :-

Mastic Gun – we've a few mastic guns and several old cartridges with contents that are well past their best and should have been thrown out ages ago.

I pumped out the remains of an old sealant cartridge and cut the end off it.   I also made a rough blanking plate from a scrap piece of thick plastic. The blanking cap shouldn't be a tight fit in the cartridge – it must let the water past –  and so it can be quite rough.

We experimented first with material from the shredder bin.   This was also an excuse to get rid of all those eBay invoices, old bills and other papers that were piling up on the shelf, and so the process began with a shredding campaign. 

The shredder bin was tipped into a washing-up bowl filled with water, mixed and allowed to soak.  The mash was loaded into the cartridge with the blanking cap at the bottom, pushing the mash down with fingers several times and adding more until it was as full as possible.  The cartridge was then loaded into the mastic gun, and the gun pumped as firmly as possible....note that water escapes from both ends, since the gun driving washer is not a tight fit in the cartridge.

shredded paper in the mash...

We left it for several minutes under pressure to consolidate, gave the gun trigger a final few squeezes, and then removed the cartridge.  Using a piece of wood as a mandrel, we held the cartridge and pushed on the blanking plate and, hey presto, out popped a damp paper cylinder. 

very simple - cartridge, rough blanking plate
and a log made from it....
in the mastic gun under pressure....

We made a few more using the mastic gun press – they were a little fragile at the wet stage when removed, but we laid them out on an old cloth for a few days and then placed them directly on top of the central heating radiators in the workshop for a few weeks.  At this time of the year we use the heating sparingly and only ever in the evenings, and so the log drying time was prolonged. 

However, the end result was paper fuel logs which were dry, hard and of sufficient strength to be handled quite roughly without falling apart.

Home-made Screw Press – I had a piece of thick-wall aluminium tube lying around in the workshop, but although it's ideal as a log mould I didn't want to damage it because it's valuable and bound to come in useful for something more profitable.  Any design I could produce therefore required the aluminium tube to be a passive component, with no cutting or drilling.

So, I made a simple screw press from a length of 8 mm steel bar that I threaded at both ends, one end with quite a long thread length.  I made a threaded end plate and loose-fitting piston for the tube on the lathe, using some plastic barstock – I appreciate that most people don't have a lathe, but you could still make these items using just a hand saw and a few scraps of wood, they don't have to be precision engineered.   Threaded steel bar is also available from DIY stores and those hardware & tool traders we see at car boot sales, but obviously if it's more than a few pounds to buy then it defeats the object of making such a press yourself. 

So now we had a log mould of roughly twice the diameter and twice the height of the mastic cartridge, i.e. eight times the volume.  Exactly the same paper preparation process as before, but this time compressed by tightening a nut and washer against the piston within our aluminium tube.

screw press - twice the size of the cartridge...

Again, our first tests were with shredded paper.  When we pushed these longer formed logs out of the tube, they generally fell into two or three pieces but we just gave each piece a consolidating squeeze by hand.  The presence of the central screwed bar also made the wet log removal process a bit trickier, and contributed to the breakages. 

However, these breakages actually turn out to be an advantage, as they produce shorter log lengths that are more suitable for the size of our fireplace. 

first batch of logs for testing....

We also made some logs from newsprint, but for these we didn't bother shredding the paper.   We just pulled the newspaper into separate sheets, folded them and laid them in the bowl of water.   After experimenting a bit with them, it seems easier to soak them for quite a long time, maybe even overnight, and mix them around the bowl by hand until you've a wet and grey muddy pulp that's barely recognisable as paper.

In this form, although they're a bit messy to handle, they make dense logs that hold together – if the papers aren't wet enough, they tend to decompress a bit and open out slightly when removed from the press, although they still dry out and burn OK.

newsprint logs - the left one was not soaked enough and has
sprung open, the right one is from fully pulped paper

In conclusion....

We found the type of paper used had a big influence on the log making – I've since shredded several old confidential client reports that were produced on a thicker-quality paper, and these logs didn't hold together nearly as well as those made from newsprint or more run-of-the-mill printer paper.   I think the trick will be to mix the thicker stuff together with the thinner when doing a shredding run.

Those logs produced using the screw press were noticeably denser than the ones made with the mastic gun.  This is to be expected, because it's possible to apply much more compressive force on the mash in the tube using the screw.

All the logs we made eventually dried out very well to make usable fuel.  So, I think we've found a couple of ways to make some totally free fuel logs.   However, they're a little fiddly and time consuming to make with these types of home-made presses – if you intend to be serious about it, maybe come up with something that's easier to load and press, for a quicker turnaround time.  If I see one of those cross-handled manual formers on an eBay auction for a fiver or so, I might even buy one.

So how well do the paper logs burn ?  They're a bit like wooden logs in that they need to be added to an established fire, but they held together and burned well enough.  They didn't leave much residual ash in the fireplace, unlike burning loose pages of paper which produces flying ash and needs a lot of cleaning up afterwards..

three paper logs on the fire...

An added benefit with these home-made paper logs and briquettes is that they're clean to handle when dry – after all, they were made from clean paper – and therefore you can store them in any indoor cupboard, unlike either coal or timber logs...

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