DIY Shop Vac Dust Collector

 Like a lot of people, after retirement I built a woodworking shop.  I looked at the commercial dust collection systems, and did not like the look of the 4" hose laying all over the shop.  I also did not think I needed the capability of running several machines at once since it's just a hobby shop.   I decided to look at the possibility of using a smaller diameter wall mounted piping system using PVC.  My logic here was that a smaller diameter with adequate CFM resulted in higher velocity, hopefully resulting in similiar performance using one machine at a time.
I also wanted to use my existing shop-vac, knowing from experience that the 5.0(peak) HP unit was more than adequate for the machines I have, as i have used it on each, manually changing the hose.
The last requirement was it had to turn on automatically, I was getting tired of "aw crap", forgot to start shop-vac first!

With all the above, the photos pretty much explain where I went from there.  1-1/2" PVC water pipe with 1-1/2" electrical conduit wall brackets made it easy to setup.  I opted for ball valves instead of blast gates, mainly because it was going to take more work to match fittings for the blast gate.  The standard 2-1/2" vacuum hose did not quite match up to the outside diamater of the PVC, but as always, the "handyman's secret weapon" duct tape, provided the solution.  I wrapped duct tape on the PVC pipe end to the size where I could use a hair dryer to expand the vacuum hose and slide the hose over the duct tape.  When the hose cooled, it made a perfect fit.

I decided early on to use the Dust Deputy cyclone and capture most of the dust and chips before they made it to the shop-vac so that I would not have to clean so often.  The other driving factor was that this allowed me to put the shop-vac above the ceiling.  More floor space and less noise.  The unit mounted easily on the drum lid with six 1/4" metal screws(not included).   I have to say, at $40 I was buying a bit of a pig-in-a-poke, but it truly  works as advertized.  I have half filled the 30 gallon drum with sawdust and have yet to empty the shop-vac or clean the filter.

I decided to anchor the PVC pipe going through the ceiling by using a floor flange for electrical conduit and drilling a clearance hole for the PVC, then gluing the PVC in place.  I also used a pipe clamp above the ceiling on the PVC.

I looked at a few commercial current sensing products to automatically turn on the shop-vac when I started one of the machines, but the cost was about $50 per machine for the remote nodes, plus the controller itself.  I, luckily, have all 5 of the machines I use the shop-vac on, on one circuit, which simplified the automation requirements as I just had to monitor one point.

I settled on a design that did not limit the current in case I did try to run multiple machines, using an Aprilaire 51 current sensing relay that is normally used for humidifier circuits triggered from the furnace fan motor current.  It is only rated for 50 watts so I used it to drive a relay.  When I first prototyped the circuit, the relay was energizing immediately.  After a replacement current sensor gave the same result, I started experimenting with loading, and determined that although the specs said 50 watt max, it should have also said 10 watt minimum load.  The particular relay I used only draws 10ma and measures 5k ohms resistive load, so I added a 2k ohm 20 watt wirewound resistor in parallel with the relay coil to increase the load and keep the relay from a false start.


The system has been running about a month, and works to my expectations, with more than enough vacuum and velocity.  One gotcha in my system is my paper barrel.   I closed all of the valves with the shop-vac on and it imploded.  Nice ad for Shop-vac I suppose.

I'm not good at writing conclusions, or writing at all for that matter, so I end here I guess.  I'd be happy to answer any questions.

Thanks,
Steve


Update - 10/30/2012
I was still having trouble after 3 months with occasional false triggers from my garage door opener.  I modified the circuit by replacing the original relay with a single contact relay and replaced the 2000 ohm resistor with a 40 watt light bulb.  It has ran well since then, with no false triggers, but I have procrastinated updating this site.

I also added a wall switch directly across the Aprilaire current sensor to aid in shop cleanup.  The switch energizes the relay to start the vacuum directly, so I can connect a 20ft hose to clean the floor.

Thanks,
Steve

Update - 10/24/2014
I added a 25 foot hose to clean the shop floor.  Looking around the one that worked the best was a swimming pool skimmer.  I added another valve and elbow, and this hose fit the inside of the elbow with duct tape where the 2 1/2" went on the outside of the pipe.
Live right I guess.  The hose reaches everywhere in the shop, even the cobwebs in the corners, and standard attachments all fit.

Thanks,
Steve



Update - 12/4/2014
Replaced the small dedicated vacuum system on my mitre saw with an extension ran across the ceiling.  The $20 vac has never quite handled the air flow generated by the saw.  I left the valve on the other side of the room, true it's not quite as handy, but can I reach it easy this way and this lets me put the flexible vacuum hose high on the wall for the swivel path of the saw.  I also ran a dedicated outlet on the wall for the saw from the sensed circuit across the room for the other tools on the vacuum system.  Again, since I only use it for one tool at a time, there is plenty of capacity of both the electrical and vacuum system.

Thanks,
Steve

Comments

[pfred2]

Have you had any issues with static electricity and your plastic piping? I've heard tales both ways, anywhere from it doesn't matter to it'll knock you across the room.

[kentdvm]

My 2 cents .... I have a cyclone dust collector and about 40' of 6" plastic pipe running around my shop. I've not had any problem with static electricity during the 6 years since I installed it. So my vote is in the "doesn't matter" category but I agree there are a lot of stories and theories out there.

[pfred2]

There are a lot of things you have to get right, er, wrong, to make a PVC vacuum system into a decent static generator. The potential is there, realizing it isn't always easy though. Running higher CFM and more drier and finer dust with drier air and you may be onto something with your 40' 6" system, then again maybe not.

What certainly doesn't matter is the static sparks cause fires nonsense. If you're running hard enough to create ignition sparks you're running too hard to support combustion. It is just like trying to light a candle in the wind. Though I believe some extremely poorly designed systems have been known to make little explosions inside them. They literally blow themselves out when they happen though.

[kentdvm]

I agree. My system pulls 4400 CFM so I'm not sure a spark would matter much. What I am concerned about is if metal hits my impeller and lights my collection of dust on fire. For my dust can I'm using a metal trash can and lid to help prevent a shop fire. That's a much greater risk than static sparks, however, I don't think it's as great a risk using a shop vac. Always something to keep in mind though.

[Ronin60]

Hi This is a constructive comment please take it as such. It is a known fact that fine saw dust and what is called flour dust will ignite with such force and ferocity that it is explosive; I am not saying that this is the case within this design; however one should take this into account when designing such systems because such explosions have levelled factories such is the explosive power! I am currently looking at designing one of the systems for my home workshop; I am versed in static electricity because I am so charged thatIi am for ever getting a belt (as we say in the electrical industry in the UK 😂

[pfred2]

What I wonder is why can't impellers be screened off? Nothing that would block air flow, but something that would stop larger chunks from hitting the blades. That is how shop vacs are. Their impellers are behind the filters. But I'm not saying put the filters on larger dust collectors in front of the blowers, but put something there.

[spstewart]

I read things on the web like that also, but so far, no trouble. I left the end cap unglued so that I can run a ground wire in the future if I need to, but thought I'd wait and see.

[pfred2]

Now that I've given it a little more thought you're likely running too low velocity and volume to make much of a charge. All running a wire inside PVC will do for you is give debris a place to lodge. That has to do with the fact that PVC is an excellent insulator, how long sparks do you think you're going to be making? You'd have to be making several inch long ones in the pipe you have for the wire to work. Victor Frankenstein would have set a cot up in your shop long before then! If you say it's alive one more time ...

If you haven't felt anything I wouldn't worry about it. I don't think you should either. But keep that cap free, you might want to expand your system someday.

[rb7054]

Thank you for writing the article, taking the pictures, and showing how you did everything. Very cool and well done sir. I hope to knock out a system like this soon.

[srowden86]

Steve - great idea and thanks for sharing. I've been exploring how to build one of these and the pvc Y and valves are perfect. A couple of things I did that may be of help is 1) bought a remote outlet that I can carry in my pocket and can start the vac from anywhere in the shop which is really handy (at least as long as you don't take it back into the house with you :)) 2) check out this video for a dust collection bucket which I've found to really work well. Maybe smaller than you'd like but may be helpful for others.

thanks again for sharing

[srowden86]

Should have read your comments as looks like someone already recommended the remote outlet...

[DBat]

That pvc pipe looks bigger than 1 1/2

[Jhajek]

Do you feel your shop vac has enough suction to handle the length of tubing you have? I am thinking about using a 6.5 hp Craftsman and a dust deputy but concerned if it will handle it. My run will be 30-35 feet before connecting to tablesaw etc. Also I am thinking on putting vacuum in a noice preventing cabinet. Do you feel it will over heat?

[RIXRIG]

I currently use the Dust Deputy atop a 5 gallon pail before going to my shop vac. I recently bought the HF 2 HP dust collector system. I really like your set-up. Would the HF be TOO MUCH power to use your type set-up with the 1 1/2" PVC and putting my DUST DEPUTY atop a 55 gallon drum? I guess what I really need to know is would 1 1/2" PVC and the DUST DEPUTY work with HF 2 HP dust collector or would I need to use larger diameter piping. and press on with building a Thien separator or baffle as some call it?.

[APSeattle]

For a hobby wood shop, I wanted to start my shop vac with a remote. I don't do electrical and didn't want to spend a lot of time and money on this. Amazon carries now a lot of outlets with remotes, but my shopvac is 15amps, 6.5 HP. I finally found a wireless remote switch system at Harbor Freight for $20 and it's rated for 15amps. Comes with 3 separate outlets (labeled 1,2,3) and a remote with 3 buttons to operate these outlets individually. Works through walls and other obstructions.

The Harbor Freight link won't paste here. Search for Indoor Wireless Remote System 3pc. Item 62575. I found this through a youtube video where the person went to HF and found a Stanley brand equivalent, but I had no luck finding that online or at HF so settled for the house brand.

[okieg8r]

Anyone on this post have any input regarding DWV vs Schedule 40? Any reason one couldn't use DWV?

[devincap]

nice set up by the way how many ball valves did you use

[spstewart]

I used five, one each for 6" joiner/planar, 13" surface planar, shaper, sander, & bandsaw. Would have used more if shop were bigger, since you only open one at a time.

[rick.troiani]

Awesome. Thanks so much for this. Exactly what I was looking for. While I'm comfortable with electronics, I have some old X10 outlets with a remote. I may just try that for awhile to switch on the vac. Thanks again!

[josh.miller.3998263]

Went did you use 1.5"instead of 2"?