Bandsaw dust extraction - help

[Jensmith]

I have tried two methods of extracting the dust from my bandsaw but neither are working very effectively and I thought maybe you guys might be able to help.

I've been cutting a plastic material and it's proving to be extremely messy with the plastic dust going everywhere including over my hands and clothes and I'm not sure why it's so much worse than wood dust....

Using the twin motor on my camvac extractor isn't making much difference despite the massive increase in suck.

This is what I have tried:

Pushing the 2.5" pipe up the dust extraction port so it is sucking near the wheel - see outside port and interior photos:





But I'm still getting a build up of dust so I tried this from an idea I saw on here a while ago. I've removed the pipe for clarity but it pushes into the round adapter:





I was hoping that it would suck the dust off the blade before it got circulated but it's not working, even with twin motors going on my camvac.

Do I need to enclose the adapter from the 3rd & 4th photos to improve suction or is it fundamentally a flawed concept?

I did see another idea on here making a plastic box to sit under the table which the blade runs through but does it work?

I'm getting piles of dust both on the wheels and on the base of the bandsaw as well as all over the surface of the table and I can see the stuff blowing everywhere. The plastic is really messy whereas wood seems much easier to control. I'm not sure what to do to resolve this.

Any ideas as to what I can do to improve the extraction?

Thanks,

Jennifer,

 

[CHJ]

Jen I don't think there is much you can do about it, the statically charged plastic particles are relatively lightweight and therefore don't drop down with the flow of the blade and stick to just about everything.

I have managed to get some relief by having an extractor inlet clamped close to the top surface adjacent to the blade, this seems to pick up a fair percentage of the debris that has travelled around with the blade.

A light misting with water in the cutting area might help reduce the static attraction but I would not recommend it's use due to the inherent rust problems and the fact that your machine wiring may not be adequately sealed.

 

[Jensmith]

Ok, I did wonder if the fact it was plastic made it worse. Guess I'll just have to suck up the mess afterwards as I've been doing.

Thanks

 

[myturn]

You could try rigging up some stiff brushes at the sides of the blade and also earthing them, this might discharge some of the static.

Chas's idea of a spray mist sounds good and will also act as a lubricant for a finer cut. I don't think the amount of moisture taken round by the blade would be any more than if you were cutting wet wood and the machine's electrics are far enough away from the cutting table not to be affected.

You might also earth yourself to see if that helps.

If you have a small nozzle that will fit your extractor hose try that close to the blade as it will concentrate the suction in a smaller area.

Give it a try and see how it goes.

 

[Shrubby]

This works for me and uses current best practice -
seal the bottom hole up it's a poor design
modify the white fitting - turn it upside down ,open at the top and the blade passing through narrow slot at the bottom.tilt the fitting down 45º (this should work with the blades airflow rather than against it as is common with many attempts at extraction)
Have a look at HSE WIS24
Matt

 

[Jensmith]

Thanks Matt and Mick, I'll give those ideas a try. The HSE leaflet was interesting too - thanks for the tip.

 

[Harbo]

I see that you have cut away the bottom bit on photo 3?
On mine I have been able to keep it the full length and it works fine with wood.
You could try running the blade through an old brush and sealing the end with tape should help?

Rod

 

[Jensmith]

I see that you have cut away the bottom bit on photo 3?
On mine I have been able to keep it the full length and it works fine with wood.
You could try running the blade through an old brush and sealing the end with tape should help?

Rod

Yes, I did. It was the only way I could get it to fit as the door of the bandsaw is angled and it would slide past otherwise and I couldn't get the connector any further up to the table either to make room.

I'll see if I can close it off a bit.

 

[Harlequin]

Hi

If you have a close look at the plastic box idea you will see that channelling of the airflow is critical to the system working.
The idea is to draw air thro an opening perhaps as wide as the hose used (2 inch or so) but to truncate the flow so it rushes thro the apex of the funnel created . The apex should be at about the level of the blade.
If you go back to school physics and bernoullie's principle etc what essentially happens here is a huge increase in velocity of airflow at the apex , this causes a subsequent drop in pressure adding to the suction effect.
Even with static the extraction is more than adequate .
Hope this helps.

Rgds
H

 

[Jensmith]

Hi H,

So you use a physical barrier to channel the airflow? I think I can see from the photos. Is the size of this funnel critical?

I also wondered why the extraction point is to the side - is this a specific design consideration for airflow? I've had problems with the dust hose pulling down my adapter due to it's weight. Possibly need stronger magnets.

 

[barkwindjammer]

What you have in those pics looks fine Jen, you just need to shroud the suction around the tables zero clearance insert (close off the sides of those little wooden battens and maybe fill any gaps with silicone sealant), and plastic has elasticity and natural static properties so will 'ping' and cling to everything around it.

 

[Harlequin]

If one were to take this further then the size of funnel etc can be further optimised but for the wide variety of bandsaws out there and design limitations due to access - you can for all practical purposes assume that the size is not critical.
Having the port on the side was simply for access.
Use a smaller length of tubing dedicated to the extraction box and tape it or fix it to the bandsaw or elsewhere nearby so you don't have a long length of hose pulling on the box.
4 neodymium magnets 20mmx5mm should be adequate.
Post some pics when you are done

H

 

[Eric The Viking]

Hi Jen,

A while back, I bought a SIP bandsaw from Olly (OPJ). It has the usual 4" port bottom-front of the metalwork, and it's useless.

Olly, however, did a superb mod to it, giving it really good extraction. He blogged it, I think, and you might find his thread on the forum. I've quickly drawn up the essentials below.

He took a 1.5" plumbing 45deg. elbow (for kitchen and bathroom waste), and cut a slot in the back of it to take the blade, and fitted it so that the shoe faces up to the underside of the insert plate. It grabs everything really well. Using the perforated plate originally fitted to the saw, hardly any dust escapes. The fitting is sleeved with a piece of pipe inside the outlet end, which reduces the diameter just enough for my vacuum cleaner hose to be a snug fit. It's held onto the bandsaw with an ordinary pipe clip, on a shaped wooden block to fit the bottom door of the saw.

Considering the comments about Bernoulli, etc. nothing escapes the slot, but there's a full draught past the blade.

Any marginal loss of effectiveness is because there's little space under the bandsaw table. Yours evidently has more room beneath. If you tried this approach you could get the shoe further up and it would work even better.

I don't need to for most purposes, but if you put grounded conductive foil on the inside (aluminium lagging tape comes in wide rolls and is very sticky), you'd get rid of a lot of static. Once in the pipe, the airflow would stop the plastic 'dust' escaping.

I'd ground the shoe to the table. You only need a thin bit of wire - bellwire or garden wire would be fine, and the connection doesn't have to be perfect. Just use a bolt, nut and washer on the foil side, through the shoe's plastic, and put the bare wire under the washer.

HTH,

E.

PS: I can't claim any credit for this - the idea and execution were Olly's!