Confused about Dust Collection

Just got off the phone with Grizzly. The G0703P has a spun polyester filter and 13.5in impeller, larger than the 12.75in on there normal 2hp & 3hp units. Although rated at 1.5hp, it draws more current, [email protected] more than the 2hp unit (9A). It would be $840 with tailgate delivery, or within $100 or so of the HF with a canister filter and cyclone added. It also includes a remote control. It has a 6" inlet compared to the 4" inlet on the HF.

Based on that I would say the HF is no longer a reasonable option given the requirements for a cyclone and canister filter.



Spec sheet: http://cdn0.grizzly.com/specsheets/g0703p_ds.pdf

DYI, your progression makes sense if you start with the HF already there. The cyclone and canister are needed improvements.

Has anyone made there own air filter putting a standard furnace filter and a fan in a box? Or added the commercially available ones?

The Canadian on the link Loren posted above ran a fan on the floor through a high end furnace filter on his bedroom floor (no box) and significantly reduced the airborne particles measured and observed.



http://woodgears.ca/dust/dylos.html

Now let me add the Penn State Industries Tempests.

The design is similar to the Clearvue but more sizes are available. The 2hp (although at 9A it draws less than the Grizzly), 12"impeller (vs. the Grizzly's 13.5") is equipped with dual nano filters. $875 stationary, $895 mobile. The mobile unit only collect dust under the cyclone. After passing the filters air is re-routed to the cyclone inlet.

The 2.5hp model with a 14" impeller is $1095.

Shipping is extra, probably around $150.



These appear to be a step up from the Grizzly although more expensive and having the remote an extra $65-$75

Interestingly, they provide fan performance graphs. These can provide more insight. These are the 2hp, 2.5hp , and 3.5hp stationary models.



The 2.5hp and 3.5hp only differ in motor/blower and filters…the filters are 20% taller on the bigger unit.

They also offer mufflers that go between the filters and the blower that they reduces the noise level 50%.

David: "...Based on that I would say the HF is no longer a reasonable option given the requirements for a cyclone and canister filter…."

Please understand that you can build/upgrade over time, if choosing the HF unit. So if money is tight at the moment, you can always take the upgrade route. IMO, do not short change the HF 2hp dust collector. It is a great way to start out while on a tighter budget and if I had to venture a bet, I would bet that there are more HF DCs being used by LJs members than of any other brand.

My personal timeline (remembering I also use a 9×16 garage door opening most of the time):

• I bought the HF "2hp" DC system $170
• +6 months, I built a DIY Thien trashcan chip separator ~$40 (includes can)
• NOW 3 years later, I just ordered the Wynn Environmental Spun bound filter for the HF. ~$170 (includes sh.)
• TOTAL SPENT = $380

And the above price of $380 gives me dust collection WITH cyclonic separator PLUS a Wynn Environmental filter. The very cheapest Grizzly, Grizzly G0703, unit with ALL THREE features is currently $804 delivered, or more than TWICE as much.

As a foundry engineer, dealing with EPA, OSHA, etc. for the last 40 years, and having a wood shop in my basement, I can tell you the HF 2hp collector is a reasonable first step.

The cartridge filter mod for it is a good step to increase filter surface area, and hence airflow while getting the particulate capture down to 0.5 micron.

A simple drop out box (a 30 gal metal trash can works well) in the duct, before the fan and filter, is a good mod to make emptying the dust and chips easier and to reduce wear on the fan impeller. A cyclone here is not necessary and drags system pressure down.

I am putting my collector in a sound deadening closet.

If I ducted it outside I would add a heat exchanger to recover temperature conditioned air.

Another stage that is very handy for a basement shop is a shop air filter. They can be had with activated charcoal filter elements to absorb fumes. Fumes is a bigger problem for me. It's not just paint and lacquer, but even wood glue, epoxy, stain, even some wood itself will stink up the house.

You will still want a good shop vac for hand held power tools like sanders, routers, etc. The best mod I made in this area is a good premium extra long hose.

HorizontalMike, how well does your trashcan separator work? Which one did you use? Grizzly has one that they charge $35 for. Sounds like an intelligent system buildup.

Crank49, you have agreed with Mike's setup. Do you have data for the pressure drop across a cyclone or the relative performance of a cyclone vs. drop out box setup like the one Mike used? In magazine reviews, such as the one in Fine Woodworking, the cyclones had little if any performance drop over use while those without had significant. The question is: where does the drop out box fall in that spectrum?

There are charts for the pressure drop across different diameter and type of ducting and ducting transitions. There are also charts for the various CFM requirements across different shop tools. Is there a chart that has the pressure drop across the tool? Grizzly has one entry that had a 2" drop from a dust hood to a 4" duct.

With a cyclone especially, there is a big penalty if the air flow drops below a required speed (fpm in contrast with volume in cfm). Some people complain their system is very loud. I'm wondering if that is because their air speed is too high. For example, 1000cfm into a 6" duct is over 5000ft/min. Penn State said their design target is 3500fpm-4000fpm with 3000fpm being too low.

"Oneida has a Smart Dust Collector in their portable line that adjusts impeller speed to maintain optimal airflow speed. However, it is frightfully expensive!



Some things I've learned.

The Grizzly 703/703P (which is $840 delivered with cart and remote) has cyclones and filters that are 1/2 the size (literally, 1/2 the size) of Grizzly's other cyclone dust collectors. A rather large difference! However, the 703 is probably enough in a small shop with only one tool active and short duct distances.

The 1.5hp 443, 2hp 440, and 3hp 441 all share the same cyclone and canister filters differing only in motor and impeller size. There is a $200 difference between the 443 and 440, but the upgrade to 220v adds $91 to the 443. The 703 includes a cart. Grizzly charges over $200 for a stand for the 440 series. There is also an optional muffler. The costs quickly add up.

I would really like to see a good reliable magazine such as Fine Woodworking or Wood finally put this stuff to rest. There is too much misinformation out there. I do know that a cyclone, in and of itself, (think Dust Deputy or a Thein baffle) slows airflow down due to the longer route the air now has to take and the added friction the air incurs. It's just like how Dyson vacuums don't suck as well as a bag vacuum cleaner. However, there are so many other factors involved once you get to dedicated cyclones, such as impeller size & design. Lastly, the information Loren provided was very informative, but it didn't show how well the fine dust was getting sucked up at the tool, which is something Pentz makes a case about. However, it is very enlightening, and points out that fine dust escapes the cyclone, so the cyclone doesn't really add anything to fine dust collection. It simply seperates the larger particles before the blower motor, which is a good idea.

That leads one to question whether or not a cyclone really isn't just an expensive toy or if it really is better than a single stage dust collection system. I think the jury is still out on that. There hasn't been a test that has given conclusive evidence that anything is actually improved.

1st, let me say that H.mike and I don't often agree on much because we are 180 degrees apart politically, I think, but I try to stay away from those discussions and I think he does as well. I actually was writing my post when he posted his; so when I posted mine, I had not seen his.

With that out of the way, to comment on the loss in a cyclone, it depends.. A true cyclone depends on pressure drop to separate particulate from the air stream. The higher the pressure drop, the better it works. In a foundry grinding operation where I had to meet EPA requirements I had to have 9" of pressure drop to get the fine silica out of the flow. Metal dust was not the problem, silica was. In a melting furnace the pressure drop to get very fine metal oxides (smoke) out of the flow was well over 26"; so high it was more economical to use bag filters instead of a cyclone. In the foundry pattern shop I only had to have 3 1/2" drop to capture the typical wood dust.

Pressure drop in a system comes from many sources. The first is inlet loss. A plain pipe sticking into a dust stream will have over 2" of loss just because of its shape. Add a flange to the pipe and the loss is reduced by 50%. Taper the connection between the pipe and the box and roll the taper into the plane of the box wall and you get that loss down to about 1/4". Then there are turns and straight runs to be added. All the various elements will add a percentage of loss. The more elements, the more loss.

Going through a drop out box will add at least one more inlet loss to the system. I usually figure about 1 to 1 1/2". This compared to any cyclone worth doing is going to be around 3 to 4" .

The cabinet of a table saw looks like a source for a significant pressure drop…restricted inlets to the cabinet and the outlet seems to be a very primitive round hole in the side of the cabinet. I'm trying to figure how much of the drop is there.

The ratings from the manufacturers are pre-cyclone inlet…so the cyclone loss should be accounted for in those numbers. Grizzly rates their 2hp canister unit at 1700cfm (no pressure/flow graph) and the unit with a cyclone at 1350cfm, presumably reflecting the drop across the cyclone and inline with your 4" of drop estimate.

I noticed that Torit is using baghouse solutions for most of the commercial woodworking applications on their website:http://www2.donaldson.com/torit/en-us/pages/applications/woodworking.aspx. However, don't all of those systems have automated cleaning with pressurized air? Isn't that a significant difference from hobbyist shops? This is a picture of a 6800cfrm school woodshop system.



The pressure drop across the table saw, a planer/jointer, and a sanding table would seem to be an important criteria for estimating the capacity needed in hobbyist shop.

This is what I did with mine and a Thien separator in the trash can.
It works very well for a moderate price.

maybe this helps

Bert, that is a nice setup. I like that it is all on a cart.

As others have already pointed out, there is a ton of information, stats, opinions, designs, reviews etc. on the web with regard to dust collection. At some point in time I think that all of us as woodworkers ponder what we can do to improve DC in our shops, either for health reasons, perceived health reasons, or just to keep the shop clean.
I started off with a shop vac (mostly used to suck up the piles of sawdust after I'd been ww), then upgraded to a 1.5hp DC with a 1 micron canister, again, mostly to keep the piles of sawdust from accumulating in the shop. It did do a good job at collecting sawdust, but as I increased the amount of woodworking I was doing I started to develop a chronic cough. This led me to start exploring my options for improving the DC in my shop. I read all the articles in ww magazines that I could find, as well as the various posts on LJ's about DC. I came across Bill Pentz's site and read it through and through. More or less, several things seemed in common on all the sites;
1) CFM ratings are useless unless you compare them to static pressure
2) The advantage of cyclone DC's is that you don't get dust clogging the filters (with the resulting loss of airflow)
3) There is a big difference between fine dust collection and visible sawdust collection. One will keep your shop looking cleaner, one will improve the air quality in the shop.
4) Adequate fine dust collection requires minimum CFM airflow at each machine (this is where the CFM vs. static pressure curves comes in handy).
I went with a Clearvue cyclone with a 5HP motor; the airflow curve was the best out of all the different manufactures I looked at, however, Penn State Industries was comparable. I no longer have my chronic cough, and I don't have to work through a cloud of dust, even with my mitre saw, which was a terrible dust producer previously.
As you've seen already from the responses to your topic, you'll get a lot of different opinions…my 2 cents is to advise you to read as much as you can on the ww sites, LJ's, and Bill Pentz's site. Then think about what you want a DC for; fine dust or to keep your shop clean?