RevRico
RevRico PowerDork
12/22/19 1:21 p.m.

Had to clean the pellet stove this morning, so I dragged in the big shop vac with a newish filter, and thought I'd follow my own advice.

I rigged this lid up for a bucket I had sitting around.

I put about 6 inches of water in the bucket and strapped the lid on. 

It worked, no power loss, no dust clouds, just a full strength cleaning the whole time. Awesome.

But then I went to take everything outside. The bucket was mostly empty, the shop vac had sucked all the water out of it. 

My filter was still dry, thankfully, by I had to hose everything out before I could put it away.

Long post short, why did the shop vac suck all the water out of the bucket, and what can I do to prevent it in the future?

Elbow for the shop vac side so it pulls air from the lid instead of straight down? Rigid pipe instead of flex hose so I can lock in bottom depth? Bigger container? Breather hole in the bucket lid?

Streetwiseguy
Streetwiseguy MegaDork
12/22/19 5:06 p.m.

So, the long hose is from the job, the short one is to the vacuum, I presume.  My guess would be that you are stirring the water up so much that the vacuum is just picking big gobs of it out of mid air.  Perhaps some sort of screen halfway down to break up the splash, and prevent the water from coming up so easily?  Perhaps a much taller bucket?  Perhaps remove the filter to avoid damaging it, and just keep an eye on the water level? 

mad_machine
mad_machine MegaDork
12/22/19 9:13 p.m.

Not sure if this would work for your ashes, but I am going to make this for my boat building

 

 

minivan_racer
minivan_racer UberDork
12/22/19 10:29 p.m.

I don't see any possible way that you can pull air out of something through water.  You need to put a spin trap like what was posted above and have the water catch the  particulate if necessary.  Essentially neither hose should be in the water.

 

Oddly enough I just bought all the stuff to build a shop vac-dust collector cart today.

SVreX
SVreX MegaDork
12/23/19 7:26 a.m.

In reply to minivan_racer :

Maybe not through standing water, but through falling water. 

If you had nozzles in the top of the tank spraying water down while you pull air up through it, you’d basically have a mini scrubber.

SVreX
SVreX MegaDork
12/23/19 7:30 a.m.
mad_machine said:

Not sure if this would work for your ashes, but I am going to make this for my boat building

 

 

Ok, I think that is neat (and I like the guy’s video), but what actually is the point?  It seems it’s just adding a 2nd collection tank to an already existing vacuum (which has a tank)

RossD
RossD MegaDork
12/23/19 7:39 a.m.

Air speed. The bucket diameter was too small so the air speed was high enough to move the water entrained with the air. 

This is my guess.

ultraclyde
ultraclyde PowerDork
12/23/19 7:50 a.m.

more air space above the water, I agree you're frothing the water enough that it's just getting sucked out. Or you could just add a second in-line small bucket as a catch can.

 

AngryCorvair
AngryCorvair MegaDork
12/23/19 7:58 a.m.

Too much air speed.  I have a retail version  of this and it has an adjustable “air leak” between the shop vac and the short hose on the bucket.

RevRico
RevRico PowerDork
12/23/19 8:40 a.m.

I'd seen videos like mad machine posted before, just been a while. That guy is using 10 gallons of space for a 5 gallon shop vac. I was using 4 gallons of space for a 12 gallon shop vac. 

Next time I'm just gonna put the water straight in the vac first, that is after all, a benefit to a real shop vac.

I have (had?) An old commercial version of this somewhere, specifically for sanding drywall, so I thought I could do my own for ashes since they're super fine too. 

 

Edit to SVrex, he's doing a separate container in the video for what looks like his wood shop. That makes sense in that you can keep the shopvac elsewhere, somewhere that it's not so loud, for dust collection while still being easy to empty. 

MadScientistMatt
MadScientistMatt PowerDork
12/23/19 9:00 a.m.

I built an industrial-sized version of that sort of trap out of a 55 gallon drum a long time ago. The motion of the air causes the water to travel along the walls of the separator. It generally requires a sort of baffling design to make the water separate from the walls and ensure the water then falls back into the bucket instead of heading for the inlet pipe.

The0retical
The0retical UberDork
12/23/19 10:40 a.m.

The answer is airspeed as stated above.

 

I gave up with that on my pellet stoves. I just let the stove cool, empty the ash pan, then use the yellow fine particulate collection bags to keep the dust from plugging my ShopVac filter.

The video seems to be more of a DIY cyclonic pre-filter. Not sure why you'd do that since you can get lids that snap to the top of the 5 gal buck for like 30-40 bucks or less and save yourself 2 or 3 hours plus material.

minivan_racer
minivan_racer UberDork
12/23/19 1:27 p.m.
SVreX said:
mad_machine said:

Not sure if this would work for your ashes, but I am going to make this for my boat building

 

 

Ok, I think that is neat (and I like the guy’s video), but what actually is the point?  It seems it’s just adding a 2nd collection tank to an already existing vacuum (which has a tank)

Sawdust tends to clog up a shop vac filter pretty quickly, this separates the dust out so the vac filter stays clean.

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