# Dust Bong?



## NickDReed (22 Mar 2021)

My dust extraction set up is a 2hp extractor pulling through a Thein baffle then out through G4 filters then F7 filters inside the garage. For the most part this is working well although the finest dust does make it through to the filters. This is fine, but means I am fairly regularly (more often than I'd like) cleaning the filters. I don't want to vent outside before I have explored every other possibility due to A) massive hole in garage wall B) neighbours potentially getting dusty C) heat loss. 

So I've been researching filtering the exhaust through water.

Its a mixed bag online as far as I can tell, and. Before I started experimenting I thought I'd put it out there to you knowledgeable folks.... Has anyone here tried a dust bong to filter there extraction? Any tips? Any success? Interested to learn for others experience.

Regards

Nick


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## Orraloon (23 Mar 2021)

Honest officer it's for blowing sawdust through!
Seriously as an engineering principle it has merit and crossed my mind too. Ocean going oil tankers use it to scrub carbon and sparks from exhaust gas. Check out deck water seal.
That said It is likely going to get expensive to build and I think a lot of energy will be used up in blowing through the water so likely need a bigger blower. Another minus is if you vent it in your garage you will drive up the humidity and cool it down. I would sit back and see if Mathias Wandal ever builds one. let someone else spend the money on R&D.
Regards
John


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## Doug B (23 Mar 2021)

Having had 2 very unexpected water leaks in the workshop the thought of willingly putting some sort of container full of water in there & blowing extracted air through it would fill me with dread 
Though I’ll happily watch someone else do it in their shop


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## Yojevol (23 Mar 2021)

The process is called scrubbing and consists of blowing the dirty air through a screen of falling water droplets. You've then got to filter the muck out of the water before it can be returned to the environment. Just blowing air through a tank of water won't work. The dust will just carry through with the air. You will also lose extraction vacuum due to the increased back pressure. 
Good Luck 
Brian


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## Trainee neophyte (23 Mar 2021)

Have you thought of making an electrostatic precipitator? Just the name makes me want to have a go. Colossal voltages, so the opportunity to kill yourself would be ever present - nothing like a little frisson of fear every time you empty the bag. All you need is a mesh screen and 4,500 volts apparently. How hard could could it be?


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## paulrbarnard (23 Mar 2021)

Trainee neophyte said:


> Have you thought of making an electrostatic precipitator? Just the name makes me want to have a go. Colossal voltages, so the opportunity to kill yourself would be ever present - nothing like a little frisson of fear every time you empty the bag. All you need is a mesh screen and 4,500 volts apparently. How hard could could it be?


Fine wood dust, electrostatic discharge, what could possibly go wrong.


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## NickDReed (23 Mar 2021)

@Trainee neophyte I mean..... Clearly I'm capable of knocking one together...... Just the electric bill that would concern me.

Found this looked slightly promising.



Less chance if electrocution but you can't have it all.


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## AlanY (23 Mar 2021)

Ooh, wet scrubber... that takes me back!


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## Sachakins (23 Mar 2021)

Looks overly complicated for a scrubber, and causing back pressure.
A simpler solution would be to exhaust into a sump (water container) above water level. And using a recirculating water/pond/aquarium pump piped to a fine mist sprayer. Easier than a water curtain construction. This would collect any airborne dust, then you could vent outdoors which will stop humidity problems in the shop that wet scrubbers cause are not externally vented. If you want to vent inside, you have vent exhaust to a dessicant filter or dehumidifier to extract moisture.


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## Spectric (23 Mar 2021)

Must be my age or generation but just like you can't bake a cake without breaking eggs you cannot shape wood without saw dust and is something that does not bother me, I just get on with the job and accept some dust. I think these days people are getting obsesed with wanting a clinically clean enviroment to live and work in, just a shame those principles are not applied to the enviroment because then it may not be littered in plastic bottles and the likes.


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## --Tom-- (23 Mar 2021)

I’m in the process of putting one together for my linisher to catch the metal sparks before they hit the filters. Seems fairly simple idea, am intrigued by how much suction I’ll lose.
Commercial spark arrestors are expensive


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## NickDReed (23 Mar 2021)

--Tom-- said:


> I’m in the process of putting one together for my linisher to catch the metal sparks before they hit the filters. Seems fairly simple idea, am intrigued by how much suction I’ll lose.
> Commercial spark arrestors are expensive



I assume that will be markedly different to a dust collector?


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## --Tom-- (23 Mar 2021)

Similar concept to this


But using a Mardon extractor unit designed for metal dust and with flame retardant filters

If you’re using it for wood dust I don’t see why you need the water element to cool sparks and a simple cyclone would be the way to go


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## TheTiddles (25 Mar 2021)

Spectric said:


> Must be my age or generation but just like you can't bake a cake without breaking eggs you cannot shape wood without saw dust and is something that does not bother me, I just get on with the job and accept some dust. I think these days people are getting obsesed with wanting a clinically clean enviroment to live and work in, just a shame those principles are not applied to the enviroment because then it may not be littered in plastic bottles and the likes.


I used to work with a guy just like you!

He’s dead now, pneumoconiosis, I think he got a couple of months of his retirement in.


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## Spectric (25 Mar 2021)

But I wear a face mask and avoid MDF!


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