To find a use for the large amount of sawdust produced from wood turning sawing firewood etc, the 2 choices had was to dunp / compost it or burn it.
loose sawdust can be burned in a wood burner but can easily kill the fire and cause a lot of smoke. decide to try and compress it back into bricks that would burn better.
I researched the options of either dry compacting and the forces need where just to beyond my capabilities.
My only other option is to compress a wet mixture and use a binder such as news pulp.
I researched on youtube and instructables to see what the other people where using.
I found all the info needed but found some of the method where a bit fiddly for me as i have a few old hand injury's that make fiddly not an option. other option made small briquettes or the process was just to slow for the amount of sawdust i had lying around about 12 fertilizer bags full to be exact.
Ive done nothing new here, just added my 2 cents worth to the mix and try to improve what others have done before to inspire my own effort. Enjoy. :-)
Thanks for looking and I hope you like my idea
Step 1: The Plan.
Even a little bit of wood turning creates a large amount of sawdust..
I decided to build a mould that would be easy to fill and compress but would would produce a larger brick than that I had seen, and have a press that would be faster to operate.
I was lucky that I had the chance to buy a Sealy No2 bench press a few months back and had yet to fin a job for it. I decided that I could modify the pressto use for this job and more usefull for other jobs.
I decided to use only what I had at hand. this would be a no budget build.
3/4" plywood (I do like the 3/4" plywood)
6" sewer pipe.
Step 2: The Mould.
The mould is made from a 6" length of sewer pipe cut square on a friends band saw My own saw has only 4" throat. If have access to a few friends large saws when I need to do jobs like this.
The pipe was marked with the use of a set square the lines are the ruler blades width apart and actually worked out very evenly spaced, 5 hole where drilled at 1" intervals along each line. I used a 6mm drill bit in the pillar drill to do this, the sewer pipe is quite easy to drill.
I used the wood back plate on my wood lathe and turned 2 disks of 3/4" plywood.
One was the same as the outer diameter of the pipe with a 6mm recess cut on one edge a snug fit for the inner diameter of the pipe, this would be the base plate.
the other would be 1-2mm smaller than the inner diameter of the pipe, this would be the plunger.
That is the mould taken care of.
Step 3: Update, Better Bottom Plate
I found that the small recess I had used on the first bottom plate was starting to get built up with loose fibers of the pulp and this had lead to the ass falling out of the mould and causing a right mess and some strong language.
to solve this I made a disk with a deeper recess and a wider lip so the pipe now fits on easier and will not be able to slip off
The new disk is again made of 3/4" plywood but is recessed about 8-10 mm and is a slightly loose fit for the pipe.
Step 4: The Press
I only had to add a flat steel plate to the press, was going to do that anyway to make it more usefull than before.
A friend said he would profile me some plate steel disks for this and another lathe project. a load spreading plate on the the press would make the press more usable.
Other than add an old bike crossbar to the arm of the press to give it more leverage and get more water out with less effort.
The press is rated at about 2 tonne of pressure, the longer arm increased this so much that the solid steel arm started it bend from me pressing hay to hard, I just rotated the arm 180* and use to much force to bend it straight again. I now know the right amount of force to use not to bend the arm again.
Step 5: The Mixture and Mixer
The mixture is 2 parts sawdust to 1 part paper pulp.
Some people soak shredded newspapers over night and then mix then. some say to soak the sawdust over night, here is mu recipe.
If the heating has been on and I have hot water to spare, I use warm water to soak the paper after only about 5mins you can use the paint mixer and it will be in pulp in a few minutes, if i have cold water about an 30 mins will have it softened up and will not take long to be in pulp.
For course sawdust I just add it to the paper pulp and turn the hose into the mix until it looks about right, it should be very a very sloppy slurry so the mixer can do its stuff.
I find that very fine dust is best mixed with the pulp and then left to soaked over night.
I use builder's plaster trugs to do my mixing as they are flexible and large enough to mix a decent sized batch.
I am going to try an electric cement mixer to do the mixing which should make the job much faster with less effort.
UPDATE: I have found that for a fine sawdust you may need to add more paper pulp to the mix or the bricks will have a tendency to crumble.
Step 6: The Method
First place the mould on the the base plate firmly and fill with the pulp mixture.
level of the mixture and place the plunger on the top and gently press down.
Now carefully place the mould in place on the press without letting the base plate falling out.
And the load spreading plate if it not fixed to the press, i used on load plate at first and the plywood finally split in 2.
Press the mould until water stop running out, if you you slack of and press again only foam should press out, its just about right at this stage.
To remove the brick from the press I turn it upside down and use the rack in the press in the
up position to tap the plunger out and this forces out the brick.
Once you get the hang of things you can press a brick about ever 30 - 40 seconds, a full trug makes on average about 15 bricks.
The press needs to be clamped down to the work surface , I have the press mounted to a work bench, the bench is weighed down with 4 12" concrete blocks. the work bench is not coping well with the pressure and is now just about goosed, i need to build a very solid bench just for the press.
Step 7: And Here's Some We Made Earlier.
The pressed bricks are stacked to dry outside for a few days, if it looks like rain I cover the pile with a tarpaulin. once they are starting to dry out well I re stack then in a shed with a good air flow where they can take their time to dry out fully.
Once fully dry I move them into storage.
I have about 400 + made, and have still not used all the sawdust.
My stove is out of action and I have not got a chance to to see how well they burn, they are claimed to have the same btu value as coal but I cant say anything yet.
I did just set a dry one alight outside to see if it burned but threw it into the mixing bucket again when it started to get out of control.
I have a rough plan as how to build a box section press that would be suitable if you don't have a workshop press, if you would like to see my idea just ask and I can sketch it up and post it.
Well that my 2 cents worth on the subject.
Comments and ideas welcome.
Thanks for looking.