Shop-Vac as DC

[Iansaws]

I currently own several shop-vacs that are all in perfect working condition 2 of which are 5 HP Rigids that are pretty powerful. I am trying to design the dust collection system for my new shop and originally planned on using one of the Rigid vacs for this purpose. For this project I also acquired 2 dust collection piping "kits" consisting of several 4 ft lengths of clear 3 inch tubing, mutiple blast-gates and various connectors and brackets. After doing my research (mostly here) I now understand that this idea still leaves the fine deadly dust in the air since the vacuum doesn't filter it well. My question is this: What if I placed the vacuum itself on the outside of the shop where it would be well protected from the elements but allowed to discharge into the outside air? My budget doesn't allow for an super DC system like everyone talks about here, so I need to do the best I can with what I have. Any ideas? By the way, here is a link to pics of my shop.

http://www.bt3central.com/showthread.php?t=33851&page=2

[LarryG]

The filtering isn't the problem with a shop vac -- you can fit it with a HEPA filter, and/or line the tub with a drywall bag.

The problem is that a shop vac doesn't move enough air to capture the fine particles. A shop vac moves a small quantity of air at high velocity. A dust collector moves a large quantity of air at low velocity. Effective dust collection requires all the fines to be swept up by the large mass of moving air that a dust collector can effect but no shop vac can manage.

But wait, it gets worse! Most of the one- and two-horsepower dust collector units that most of us have in our shops won't move enough air to get the smallest and most dangerous particles, either. I have the popular HF 2HP (really more like 1.5HP) unit, plumbed with 4" hard pipe for lower resistance than hoses give, and equipped with Wynn's spun-bond polyester filter. While it does an excellent job of grabbing all the big chips and coarser dust, it still allows a fine coating of dust to settle on everything in the shop. The reason is that despite the hard piping and the highly-efficient Wynn filter, this unit's impeller is incapable of moving a sufficient quantity of air to capture all the fines. My system is helping me keep a cleaner shop, but it's not doing much to protect my health.

[cabinetman]

My question is this: What if I placed the vacuum itself on the outside of the shop where it would be well protected from the elements but allowed to discharge into the outside air? My budget doesn't allow for an super DC system like everyone talks about here, so I need to do the best I can with what I have. Any ideas? By the way, here is a link to pics of my shop.

Here's a suggestion that might get you by with what you have until you can afford to upgrade. If you duct your vac outside, and it's strong enough to carry out heavy chips, it's likely it will carry lighter dust. You might try a few variables. Depending on the size of the vac, one of the separators that fit a 5 gallon bucket, or one that has an upper bag may facilitate better flow. You could experiment with varying hose diameter from initial pick up, to the hose transfer out to the vac.

Just getting the vac outside would be an improvement. Can't hurt to try.
.

[LCHIEN]

a stop-gappish solution at best.
Shop vacs pull in the neighborhood of 50 CFM. DCs 500-1000 CFM and up.
The velocity is high in both cases but dependent upon the hose diameter.
the velocity is imporatant to capture chips. The air flow is important to suck in as much as possible since cutting usually tends to shoot fines in all directions.
A DC does about 10 times or more better at sucking in stuff due to the larger air flow.

you can filter fines with a HEPA filter on your vac. Most shoip vacs this is an available and modest cost replacement filter.

Finally if you shop has air conditioning or heating exhausting outside will suck outside "makeup" air into your shop.

[JR]

There's nothing really wrong with your idea, although it might work only marginally well. When you put the shopvac outside, you'll probably have longer runs of duct/pipe, so the shopvac will have to really be cranking to pull the dust that far. By and large you want a shopvac to be right near the tools.

Here's another approach. Do the hepa filter idea previously mentioned, even while recognizing its limitations. Then build an air cleaner. Many woodworkers have been able to scrounge old squirrel cage fans from a HVAC contractor doing upgrades. Build a box designed to use off the shelf filters from HD.

Even if you had a mondo DC system you'd want an air cleaner. This approach could get you in for a modest cost. You could then consider upgrading any part of the system as your budget allows.

JR

[Bruce Cohen]

Sorry Guys,

I got to disagree, I've been using a sears 16 gal vac as a DC, but for only one machine at a time.

I never let get the barrel get more than half- filled and I clean the filter at every dump.

I find that it does the job for my Rikon Deluxe 14" BS, a Rigid 6" Jointer, Dewalt 735 Planer, my BT 3100 using a "Y" connection and a Shark Guard.

Also it works perfectally with a Dewalt ROS disksander, to the point I no longer have to wear a mask when sanding, dotto for my PC Biscuit Jointer.

I've had the vac for about 10 years, never had a problem with it and always use it with a Sears plug in actuator (turns on vac when machine starts.

Given the choice and the room, I'd hands down opt for a real DC system, but unless I put in the laundry room (which is behind the garage) and piss off the wife, that ain't happening.

Merry Christmas,

Bruce

[Popeye]

I used the setup that you have for several years and passed it on to someone else who is still using it. There are much better systems as has been noted but you do the best you can with the funds you have available.
Rant ON: I'm sorry, but at 54 I've finally come to the conclusion that I'm going to die of something and it may as well be sawdust, but it probably will be the cigarettes I gave up 4 years ago.
Keep improving your DC system as time and money permits but I don't think there is such a thing as a dust free woodshop. People that can only see themselves working in a dust free shop should probably find another hobby. Rant off:
Have fun, be safe. Happy Woodworking. Pat

[rollo]

get a real DC or 2 stage vac

Ian: I did what you are doing for about a year, and didn't have good luck. Using a single-stage shop vac, I was CONSTANTLY cleaning the filter. As soon as the filter got a solid layer of fine dust, the suction power would drop, and the performance degrades very quickly. The shop vac is great for machines that make chips (jointer, planer, etc) but the filter quickly clogs up with extended sanding and sawing sessions. With a 2 -stage DC, you make far fewer trips to the garbage. My 2 cents.

[cgallery]

A few points:

(1) My Ridgid WD1450 vac is rated at 169-CFM. I bought an anemometer and was able to measure it at 163-CFM. It should also be noted that this is substantially higher than the big $$$ Fein and Festool units, and the Ridgid is pretty darn quiet, to boot. They make a WD1850 rated at 203-CFM, too.

(2) For best results when using a shop vac, make sure you use bags. This will keep the filter clean and make emptying easier and neater.

(3) If you generate lots of chips and don't want to burn through bags, add some sort of cyclone in front of the vac. This will extend the life of the bags considerably. My design:

http://www.cgallery.com/jpthien/cy.htm

There will be a penalty for using a cyclone (in terms of CFM). Tradeoffs and compromises...

(4) The shop vac will certainly outperform a DC on many tools. Most any handheld tool (with 1-1/2" or smaller port--DC's just can't handle such small ports). I also have a 9" bandsaw with a 1-1/2" port, so shop vac wins there, too.

Another example? Router down-draft boxes. The idea is to pull as much debris into the drop-down box through the bit clearance in the top. I've noticed lots of people using a DC for their down-draft boxes adding quite a few holes/vents to their boxes to allow any air to flow at all. But in doing so, they are further reducing the amount of air coming via the bit aperture and allowing more fine dust to escape. A shop vac will probably work better for this than a dust collector.

Yes, a dust collector would work better for my BT3K saw (even through the 2.5" port). But woodworking is often about compromises. In my case, most of my tools lend themselves towards use w/ a shop vac, and I don't have a lot of room. So shop vac (properly equipped) it is.

[jhgrady]

Rudy:

Thanks for your thoughts, that 2nd stage of yours is impressive.

I have the 12 gal HD vac, can I use bags on this and if so, where do I get them?

Thanks,

John

[cgallery]

Rudy:

Thanks for your thoughts, that 2nd stage of yours is impressive.

I have the 12 gal HD vac, can I use bags on this and if so, where do I get them?

Thanks,

John

Whether bags can be used on a vac or not depends on the design of the vac. The inlet tube must extend into the vac from the front (not top cover) of the unit.

Most of the older Ridgids have their inlets on the top cover, so they can't use a bag. But yours may be one of the exceptions.

[Garasaki]

A note: I've been using a shop vac as DC for about a year now, all the while saying to myself "this is only temporary, I will get a real DC next month...".

I go thru the bags pretty quick - one a month easily under moderate use. At nearly 10 bucks a pop, the 80 or 100 bucks I've "wasted" on bags so far would have payed for a half a HF DC. And it would have been a lot more effective.

So take a good look at where you want to be - I definately wish I would have just bought a real DC a while ago and saved that 80 bucks worth of bags...

[cgallery]

A note: I've been using a shop vac as DC for about a year now, all the while saying to myself "this is only temporary, I will get a real DC next month...".

I go thru the bags pretty quick - one a month easily under moderate use. At nearly 10 bucks a pop, the 80 or 100 bucks I've "wasted" on bags so far would have payed for a half a HF DC. And it would have been a lot more effective.

So take a good look at where you want to be - I definately wish I would have just bought a real DC a while ago and saved that 80 bucks worth of bags...

The bags can add-up. There are less expensive alternatives:

http://cgi.ebay.com/SHOP-VAC-906-62-...sid=p1638.m118

The argument between DC and shop vac is strange because I think most people that have a DC will also admit to using the shop vac quite a bit (for sanding, or with a router table). The DC won't do it all, and neither will the shop vac.

[Garasaki]

I think using the drywall/fine dust bags are important - I'd rather not spew fines all over the place. Same argument as why the stock bags on the HF DC make it worse then not using anything.

I noticed a big difference when I switched to the drywall bags. Standard bags left a very obvious layer of fine dust all over my garage. Much less so with the drywall bags.

When (if?) I get a real DC, I certainly won't be throwing my shop vac away. It's useful for 1000 things. However, I definately believe a true DC would be much better for a majority of my woodworking functions.

[niki]

I'm using only shop vacs (space) but I don't have Planer nor Thicknesser so it satisfies all my needs...

You can eliminate the need to change bags so often if you'll make something like this


Or


My table saw blade is shrouded and the shop vac removes all the dust very easy.

With the "modified" shop vacs, I have to change the bag maybe ones a year on the "home vac" or clean the main filter (I don't remember when I cleaned it last time) on the R2D2.

One must "dare" and modify a brand new shop vac like I did and I know that not many people would dare...

After I added the "Hammer", I don't open the vac at all just "Bang" the "filter" a few times....

When the "Hammer" does not fully fall down...I know that it's time to empty the can....

niki