Thread: Saw dust disposal

I take my (plastic) drum outside and upend it into a plastic bag, while wearing a dust mask. I use a length of 2-inch PVC pipe to allow air into the bag down the side of the drum. But then, my drum is 110-120 liters. Don't know if I'd want to try to upend a 240L wheelie into a plastic bag.

You could make a frame (e.g. out of steel rod) that goes inside the bags to hold them in place inside the wheelie. The frame is pulled out of the bags at empty - might spill some dust but not much I wouldn't think. I can't do this for mine as my drum is narrower at its top.

For more info on the frame in the bag idea, see this thread on the Clearvue forums: http://www.clearvuecyclones.com/Bull...read.php?t=877.

Greg

We face the same problem and our plan is to get 3 bins.

Apart from a couple of all day thicknessing sessions of raw pine (the chips fromwhich went to SWMBO's Stables) I wouldn't put any of the sawdust arched generates near a compost heap. The chips contains too much paint, MDF and metal The local council is a major sponsor of our shed and they say they will take it away as part of their normal rubbish collection

Making a wheelie bin work under a cyclone can be a bit difficult due to air leakage. I have seen it done well and seen it give major problems because enough care was not used in making an airtight lid and depending on the bin sealing the axles if needed. The lid is the major problem in most cases and the people who got it to work were more than happy with the result.

I either bag mine up and put it in the wheelie bin or give it to my partner who mulches the garden with it.
Large workshops in The U.K and other countries spend big money on Briquette making machines so they can burn them in a special heaters to keep the workshop warm in winter,and summer as well !

Originally Posted by mark david

I either bag mine up and put it in the wheelie bin or give it to my partner who mulches the garden with it.
Large workshops in The U.K and other countries spend big money on Briquette making machines so they can burn them in a special heaters to keep the workshop warm in winter,and summer as well !

My cousins in northern Italy run a large semi-CNC style mill that can take timber up to 600 x 600 x 13000 mm and turns out kits that make up complete houses. Mostly they do replacement roofs. This generates very large volumes of sawdust and lots of old roof timbers that they feed to a furnace and heat water which they send around a closed loop to 20+ factories in their area. In summer they just burn the sawdust and make an install a lot of roofs. They stockpile the old roof timber until winter when there is a greater need for heat.

The factories used heat exchangers to heat their factories and for hot fresh water. It took a few years to recover their investment but they now are making good money out of the whole deal. The alternative for the factories is imported oil or gas from Russia (i.e. not that reliable).

One method that I have seen around the Internet for keeping plastic bags under control in Cyclone type separators is to get a large sheet of semi-rigid plastic - HDPE or similar - about 1mm thick cut so it is as high as the bin and a bit longer than the circumference of the bin. The plastic sheet is then coiled up and slid inside the bag before putting it in the bin and when the bag is nearly full the sheet of plastic can then be gently withdrawn leaving the debris behind.

As for brslee above but we used normal sheet laminate rather than buying plastic sheet. Cabinet makers so we had heaps of oddments and offcuts we could use. Dusty on the CNC router wasn't a cyclone, but a 10HP blower system with a 44 gal (205L) drum and very fine filter inline before the blower so the drum was under considerable vac when operating but the laminate stopped the bags getting swallowed. We could not find an economical bag that could carry around 180L without ripping during or when removed.

a 240 litre bin of sawdust / wood chips will weigh 50 to 60kg, which is an OHS issue of itself

I suggest you use a smaller bin and continue with the 100 micron bags.

Might I recommend for the regular 2 and 3hp dusties the bags from Hare Forbes Machinery Warehouse. They are REALLY thick and I haven't managed to mangle a single one yet.

A bag is filled in a week. I just pop it off when 4/5ths full and fold the edges over carefully and tape it closed with brown boxing tape (6 rolls is $12 at Office Works). This is then left on the nature strip for 3 minutes until someone bungs it into the back of their car! On the side I use a fat sharpie "FREE SAWDUST! Take me home!" ..... 3 minutes would be average....

If I'm stupid and overfill it (Im stupid a lot), I use the white shopping bags from woolworths to tape a simple cap inside before folding it all over. The double layer is strong and the tape sticks to them like superglue.

Tgbrooks, to your question on internal bags, there is a solution that doesn't involve bricks. I can't find an image, but follow this.... on the bin, drill a small hole and fit a small hose into it. 5mm ID clear hose from Bunnings is heaps. Run the hose to the inlet side of the impeller. Not in the impeller, but the connection leading into it. Drill another hole there and insert the hose in 5mm or so. Seal the holes well. The vacuum from the impeller inlet creates suction inside the bin. The outside of the bag is sucked hard against the inside of the bin. Naturally the lid must be sealed on the bin for this to work, but it would be anyway otherwise you'll have a Sahara level dust storm to contend with. This "inflates" the bag to occupy the fullest extent of the bin possible.

This is exactly the same idea as a PCV hose on your car engine. A hose runs from the top of your rocker cover to behind the venturi on your carby. This creates a permanent vacuum inside the engine block. Any nasty fumes and piston blow-by are scavenged/sucked out and burnt by the engine. On a car there is a one-way valve on the pipe to contend with backfires, but I have never heard of such an occurrence on a dust collector

This only works where the collection bag is in a receptacle, not on regular DC's.... BUT it does lead one to the inevitable conclusion of using a cyclone inline with a hefty DC and fat pipes .... BobL's territory there....

Originally Posted by Evanism

A bag is filled in a week. I just pop it off when 4/5ths full and fold the edges over carefully and tape it closed with brown boxing tape (6 rolls is $12 at Office Works). This is then left on the nature strip for 3 minutes until someone bungs it into the back of their car! On the side I use a fat sharpie "FREE SAWDUST! Take me home!" ..... 3 minutes would be average....

If I have anything I want to get rid of I put it on the nature strip and put a sign on it saying "For sale - $20" It is usually gone pretty quick whatever it is but nobody has ever knocked on the door to give me the $20 either. If I just leave it out without a sign or a sign saying it is free it sits there for ever. This does not bother me. Maybe one day someone will pay for it but I doubt it in the western suburbs of Melbourne.

The good thing is that they usually pull the sign off an throw it on the nature strip so I can use it next time. Saves me making a new one.

Thats life I suppose.

Cheers

Doug

Originally Posted by Chris Parks

Making a wheelie bin work under a cyclone can be a bit difficult due to air leakage. I have seen it done well and seen it give major problems because enough care was not used in making an airtight lid and depending on the bin sealing the axles if needed. The lid is the major problem in most cases and the people who got it to work were more than happy with the result.

Chris,

I was planning to make a new lid from 19mm thick MDF with a groove routed to the shape of the bin top lip - probably about 10mm wide and 10mm deep with soft rubber inserted as a seal. The axles on the Wheelie bins we have do not intrude into the bin, in fact they hold water very well.

Trevor

Originally Posted by ian

a 240 litre bin of sawdust / wood chips will weigh 50 to 60kg, which is an OHS issue of itself

I suggest you use a smaller bin and continue with the 100 micron bags.

Ian,

I had not considered this aspect. The 3hp dust extractor we currently have connected to the thicknesser and jointer has 2 bags of about 150 litres each and the shavings are not very dense and are OK to drag sideways but would be difficult to lift vertically (out of a large wheelie bin). Add in the fine dust from machines such as table saw, mitre saw and bandsaws that is more dense and its is going to be a bigger issue. The problem with a smaller bin will be the need to empty it probably every day or more often. We currently fill 2 or 3 bags a week from the thicknesser and jointer alone. Back to the drawing board !

Trevor

Originally Posted by BobL

We face the same problem and our plan is to get 3 bins.

Apart from a couple of all day thicknessing sessions of raw pine (the chips fromwhich went to SWMBO's Stables) I wouldn't put any of the sawdust arched generates near a compost heap. The chips contains too much paint, MDF and metal The local council is a major sponsor of our shed and they say they will take it away as part of their normal rubbish collection

Bob,

We were planning to use multiple 240 litre bins as well . We don't allow milling of painted material at our club and there is only a small amount of MDF and chipboard cut on the table saw. The local Community Garden use our sawdust waste for "hot" compost, our main issue is the logistics of getting it to them without contaminating our workshop or local environment getting the sawdust out of the wheelie bins.

Trevor

in terms of lifting a bag of sawdust and shavings, if you don't want to install a crane, I can't see a solution other than to keep the bag volume to around 100 litres.

perhaps you could mount a number of 100 litre skips on a trolley so that a fresh skip can be rolled under the cyclone each day or so.
Then the sawdust would only need to be emptied when all the skips were full.

alternatively, you could mount a supperceded DC outside and use it to vacuum out the wheelie bin into smaller more easily handled bags.