Compressed Sawdust

[peds]

On 25/04/2022 at 19:59, trigger_andy said:

 

 

You must spend a fortune when you drive into town solely for Milk. Then the next day for Bread. Then the next day for butter……..

 

 

You could... buy them at the same time? 

 

Or... you could just not be contrarian for the sake of it.

[trigger_andy]

2 hours ago, peds said:

You could... buy them at the same time? 

 

You know that was my point, right? 

Edited April 27, 2022 by trigger_andy

[peds]

Do you know what, you could be right. You win this round, Mandy!

 

Anyway, I'd be looking at using a mix of old cooking oil and beeswax... the dark brown stuff you harvest from 4-year-old brood comb that isn't fit for much else, not the clean yellow stuff.

This might not work for people without bees.

 

[DocMustard]

Back to the post subject, Fox Blox are made by a Lancashire timber moulding company from all their shavings. Their website states that the shavings are compressed using a load of 1700kg per square centimetre, in order to force the lignin to bind the wood fibres together.

So based on a block surface area of, say, 20 x 10 cm (or 8 by 4 inches) this equates to a load of 340 metric tonnes compressing it. (200 square cm @ 1700 kg). That's a fair piece of machinery!

[Rob_the_Sparky]

2 hours ago, DocMustard said:

Back to the post subject, Fox Blox are made by a Lancashire timber moulding company from all their shavings. Their website states that the shavings are compressed using a load of 1700kg per square centimetre, in order to force the lignin to bind the wood fibres together.

So based on a block surface area of, say, 20 x 10 cm (or 8 by 4 inches) this equates to a load of 340 metric tonnes compressing it. (200 square cm @ 1700 kg). That's a fair piece of machinery!

but it is the heat that softens the lignin from what I understand not just the pressure.  That is why this sort of equipment is not really viable unless you have a LOT of dust and, I suspect, are going to sell it.

[openspaceman]

1 hour ago, Rob_the_Sparky said:

but it is the heat that softens the lignin from what I understand not just the pressure.  That is why this sort of equipment is not really viable unless you have a LOT of dust and, I suspect, are going to sell it.

Yes that is my understanding too. Similarly when one steams wood in order to bend it it works because the cellulose fibres are the tensile strength of the wood and the lignin is the stuff that binds them all together ( like glass fibre in polyester resin). Heat the lignin and it loses some stiffness and can flow and reform as it cools.

 

My boss sold his briquette making machine before I could see it working but that hammered a wadge of sawdust through a 2" die and, again, it was the heat generated from the friction of the sawdust binding in the die that caused the softening of lignin.

 

If you watch pictures of the shimada screw press working you can see both steam and smoke rising from the emerging briquette from this friction generated heating, often the briquesttes emerge with a charred surface. About 2:30 below.

 

 

[AHPP]

I have a plan to one day have a box trailer with an electric screw type briquette maker in the back, drive it to joinery workshops, use their electricity and their dry sawdust to extrude briquettes straight into the trailer and then park it next to the burner at home.

[doobin]

3 hours ago, AHPP said:

I have a plan to one day have a box trailer with an electric screw type briquette maker in the back, drive it to joinery workshops, use their electricity and their dry sawdust to extrude briquettes straight into the trailer and then park it next to the burner at home.

Or you could just use a couple of trees you’re being paid to cut up anyway?

 

Sorry, I’m doing an Andy! 🤦‍♂️🤣

[AHPP]

1 minute ago, doobin said:

Or you could just use a couple of trees you’re being paid to cut up anyway?

 

Sorry, I’m doing an Andy! 🤦‍♂️🤣

Aye, that too. As ever, I want backups to backups.

[scbk]

4 hours ago, openspaceman said:

Yes that is my understanding too. Similarly when one steams wood in order to bend it it works because the cellulose fibres are the tensile strength of the wood and the lignin is the stuff that binds them all together ( like glass fibre in polyester resin). Heat the lignin and it loses some stiffness and can flow and reform as it cools.

 

My boss sold his briquette making machine before I could see it working but that hammered a wadge of sawdust through a 2" die and, again, it was the heat generated from the friction of the sawdust binding in the die that caused the softening of lignin.

 

If you watch pictures of the shimada screw press working you can see both steam and smoke rising from the emerging briquette from this friction generated heating, often the briquesttes emerge with a charred surface. About 2:30 below.

 

 

I like how at the start of the video it says "The main raw material is softwood logs" and shows a wood handling yard full of good logs.

 

Then at the end of the video you see the shrink wrapped and plastic strapped bag that says on it "Made from 100% recycled wood"

 

The wood is only recycled because they chipped it in the first place 

 

 

Huge amount of energy and machinery used to smash up logs and stick them back together in the shape of a log, with a bit of waste sawdust mixed in.