whilst on the hunt for a cheaper way to heat my 1930s house I visited a local showroom selling heat logs made from sawdust. I was totally amazed at the cost of these, approx 35p each or you could buy a ton for approx. £400 plus, which seems exhorbatant. I wondered if I could make these myself, as sawdust is relatively easy to come by.

I have searched the web but can only find machines for large commercial use. I was advised by one Company that small machines do exist but they could not tell me who produces these.

Does anyone know where I can buy a small domestic machine, and has anyone tried making these logs themselves. I am sure any money spent would be easy to recoup.

www.renewablefuels.co.uk

About 20% less per tonne.

Depends where you are in the country if you do enough scouring around you may find a local supplier (I did £150/tonne), dont forget the cost of transport in pounds and environmentally is what ramps it up.

£400 a tonne? ...sounds very steep to me!

We're looking at £20-£40 a tonne incl. delivery for dry wood chip (mainly from old pallets) on one of our social housing projects. That is for a communal heating plant not a single dwelling, so the fact that it's unprocessed chip and a larger order means that it's not directly comparable.

However, assuming 4000kWh/tonne for dry woodchip gives about 0.5-1p kWh. I don't know how good these sawdust logs are, presumably fairly dry, so assuming 4700kWh/tonne (often quoted for wood pellets) gives about 8.5p/kWh, which is similar to the cost of electricity.

Skywalker, the logmaker looks interesting, although I'm not sure why it took him 10years to develop it, it's basically just a tube with a plunger, unless I'm missing something?

You miss nothing Olly - no flys on you

The same, presumably, can't be said of dickster after his cowpat experiment!

We looked into wood chip/pellet also but the lack of a local supplier & the need for a big very dry storage area and operating area for the automatic version along with the cost of plant scared us off. I think it wound up being around £10K - makes my heatstore look cheap (sort of).

Has any body found a glue for binding sawdust?
I am using a 12 ton press to make logs but still have not found a good binding agent.

jakeswarm, I believe if you compress it high enough the lignum in the sawdust binds it all together.

try these sites for machinery
http://www.rictec.com.sg/briquetting/sawdust-briquetting-presses.php
http://www.woodtech.co.uk/products/productdetail.asp?ProductID=82
http://shimada.co.uk/Shimada-Extrusion-Press.php
if you look at their figures you should be able to extract enough info, IE power consumption to tonnage produced to get an idea of the compressive force, or build the heaviest press you can with a tapered barrel end and if they come out loose reduce the orifice an try again. the amount of pressure is fairly large and the briquette will come out hot, as one link shows
tom

Try Portland Cement!

jakeswarm,
I presume your cardboard tubes are 100mm dia or there abouts, if so, to get the sawdust to bind I think you would need a press of 50 tonnes or more, the ones I've seen extrude through a 50mm orifice with so much pressure that the briquette comes out very hot (steaming !) and at times even slightly charred which helps the natural resigns to bind it.
Tom

Cow dung does actually work, my attempt was a bit halfhearted though. If you're thinking of spending oodles on a press, maybe try it first beforehand. As I said, it isn't smell free, but my old squirrel stove leaks a bit. How much energy is the press going to use to enable you to conveniently get energy out of a sawdust briquette? Eco is always a tricky beast.

Hello Firelogs.
Thanks for the info. I dont think I'll bother trying to make logs for my fire.
If you need an agent in wales let me know.
Cheers.

Firelogs

Like you, I stumbled across this site recently. I was very interested to read your comments as i have been trying to find either a supplier of wood briquettes at a reasonable price, or a local manufacturer (so that collection from them is financially viable), or both, and have so far drawn a blank.

Whilst I wouldn't want to tempt you to put your prices up, you seem to be selling slightly more cheaply than the next cheapest I've found. Unfortunately you are on the opposite side of the country to me (I'm in Somerset). I don't suppose you have or are planning to have any outlets nearer here?

In the face of the high price of these briquettes, like several other contributors to this forum I have been looking into the practicalities of 'domestic' briquette production. Again, your comments were informative and somewhat sobering! Assuming such a thing as a 'domestic' scale press were available it would be possible for the 'green enthusiast' to manufacture their own briquettes, or is the 'black art' side of production that it's taken you several years to learn going to make it impractical (assuming of course that a source of kiln-dried material could be found)?

I've seen small-scale industrial presses available in the £8-10k price bracket (!!!) - I don't suppose anyone knows of any cheaper models?

I assume that everyone who contributes to this forum is, like me, keen to be 'green'. It seems to me a great shame that this form of energy is generally so expensive as inevitably despite our worthy intentions few of us can afford to pursue an option that is significantly more expensive than less green alternatives.

Simon,

Yes there is a natural glue, cow poo, as previously discussed. It works and there's plenty of it about. All we need is a sawmill next to a dairy farm with slurry mixed with sawdust, bit of a sausage machine and there you go!

Hi All.
I can go back to just after the war in 1946 where my Saturday job with my father was to make briquettes for the stove and fire grate for the next week.
Dad was a coal miner and a family member had a small saw mill at the bottom of the street, so we had plenty of small coal and sawdust. This is how we made briquettes, dad was good with his hands, and a friend in the colliery machine shop. Somehow the shed had a new piece of kit an old hand fly press, the one with a big ball at the end of handle, 10 pieces of 3" pipe about 10" long, these I filled with a mixture of small coal and sawdust from a pile that I had mixed before hand and kept filling until the mix was used up { 1 bucket of small coal 2 buckets of sawdust and a spray with a weak solution of wall paper paste until damp} . One good pull on the handle brought the form into the 3" pipe and your briquette was made. Dad kept making these for years until the saw mill closed and move to a bigger place.
The ever increasing cost of Gas and Electric has brought Wood burning stoves and Briquette making to my own family, now being retired and have time to research this project, I have found some facts that would be of interest to you all.
Sales of wood burner stoves has risen by 40% this year compared last, so there is growing market out there for Briquettes.
The only small machine that I have found on the web is from China, they give the price of larger m/c at USD 4000.
Still pricey for one family, but I thing OK for group.
OK if you put into google 9YK Series Briquette Machine it will pop up, or you could use my simple design on the same principle as the fly press, let me know if interested??
Good Luck.

Yep, They used to sell them in the 'Innovations Catalogue' - remember that?

http://www.presentsformen.co.uk/product.asp?pf_id=6925&gclid=CLy33PaFvpYCFQIyxwodrWuixA