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Dust Collection advice, please

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Forum topic by baldguy posted 08-23-2014 03:25 PM 510 views 0 times favorited 14 replies Add to Favorites Watch
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baldguy

9 posts in 26 days


08-23-2014 03:25 PM

I’m building up my garage woodshop, and I have most of it laid out in a way that I think will work. I’m struggling with the dust collection parts, though. Since I’m acquiring a lot of new (to me) tools at once, I’m trying to find good deals. Today I picked up one of these Shop Fox 1.5 HP units locally (as part of a package deal with a 8” Jet benchtop jointer/planer):

http://www.northerntool.com/shop/tools/product_200481385_200481385

My first issue is that this unit has a 6” inlet, reduced to two 4” ports. My TS has a 2.5” port and my router table, the jointer/planer, and SCMS are smaller than that. I don’t yet have a band saw but I believe it will also be 2.5”, if I get either of the two Delta ones I’m currently looking at. My intention is to build a new cabinet this weekend for one wall of my shop that will also become the stand for the SCMS and the router table. Given the amount of dust that the SCMS generates which escapes dust collection entirely, I intend to put in some sort of scoop behind it to try and grab what it throws back at the wall. I want to tie that scoop and any other collection points (on tools or otherwise) into a single line that runs hidden within the cabinet. I’ll put reducers and blast gates in all the right spots for all the various tools, but I’m thinking this branch of the line should be 4”. Then I’ll run another line from it overhead and back down to the other wall where the shop fox will live. Does this seem sane?

My second issue is filtering – my previous DC solution was just a little shop vac. While it is loud, small, and fills up quickly, it also has a HEPA filter to get a lot of the really fine dust. This new dust collector does not have that filter. It only has the bags, which according to the link above are rated to filter out stuff down to 30 microns. As I understand it, this still leaves lots of fines for me to breathe in. Is there a way to replace those cloth bags with a top filter and a bottom plastic bag? Or some other solution that will get the smaller stuff?

Lastly, I simply do not have room for a big clearvue cyclone or anything like it. I might be able to squeeze in a DIY chip separator or something to get the big stuff before it goes through the impeller. Is that a good idea? With all the chips that the jointer/planer will throw off it sure seems like something should stop them before they get a chance to whack some impeller fins.

I’m a total woodworking newbie, but I do have a background in engineering. I tend to overthink stuff, so I’m hoping that you more seasoned folks can help steer me in the right direction.

Thanks!


14 replies so far

View sawdustjunkie's profile

sawdustjunkie

166 posts in 370 days


#1 posted 08-23-2014 03:35 PM

First off, if this is the size of what you want, go get the HF one. It’s the same and can be bought for under $200 with a coupon that they always have.
I got my HF for $165 last year. Went and got a Super Dust deputy and mounted it on a piece of MDF and it is sitting on a 35gal trash can. I also got the Wynn air filter instead of the dust bag. Better for your lungs.
As for the ducting, I got reducers from Home Depot to bring everything down to 4”. they can be found in metal for furnace installation.
I really don’t think it would work very well if you tried to reduce it to 2.5”.
I have the small dust Deputy attached to a shop vac for that and it works great, but not enough airflow for a table saw or plainer.
My shop is also in a garage and I never have more than 1 machine running at a time, so I only use a Rockler 4” flex hose that is connected to the Super Dust deputy.
Good luck with your project.

-- Steve: Franklin, WI

View Fred Hargis's profile

Fred Hargis

1784 posts in 1147 days


#2 posted 08-23-2014 03:43 PM

Baldguy, I say this with love in my heart, so don’t take it the wrong way. A 30 micron bag is next to useless, it makes your DC little more than a dust recirculating pump. That actually won’t matter if you choke the DC down to 2.5” since it will catch very little dust choked down like that. I’d revise your plan; start with better filtration on the DC, 1 micron or better, that gets the finest particles. Filters are available from companies like Wynn and PSI, though you may have to fab up some baffles or such to fit them on. Bags can be had from American Fabric Filter, since these are made to order, you can get an oversized one for the top, and still use a plastic bag. Then, don’t assume your constrained by those puny ports that many manufacturers put on their tools. Upsize them to the line of your duct. This takes some modifications, sometimes cutting into the machine itself. A common bandsaw re-fit is to simply cut a 4” hole in the lower door and put a flange on it for the DC hose.The preseperator is a good idea, it will catch most of the debris, and will be a whole lot easier to empty than the bag. That said, those single stage impellers are usually built to withstand some abuse so an occasional wack doesn’t really do much damage. One last thing: air flow is the most important thing (well, next to tight filtration) in DC. Any reductions in the lines will restrict the air flow and should be avoided….remember, 4” ducts will only carry 400 CFM (+/-), reducing them further isn’t good.

-- Our village hasn't lost it's idiot, we sent 'em to Washington.

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baldguy

9 posts in 26 days


#3 posted 08-23-2014 03:46 PM

well, I already have the shop fox. I got it with the Jet jointer/planer for $350 total from a local guy who now has much better and more expensive tools to replace these, but took very good care of them. I felt like it was a great deal and I’d love to find a way to make this one work.

Correct me if I’m wrong, but just based purely on the laws of aerodynamics, doesn’t reducing the inlet actually increase the air velocity at the tool? The same volume of air that should have served a 4” port is now coming through a 2.5”... I guess I’m just not grasping how that could be a reduction in performance. If it is though, I’ll figure out something else.

View baldguy's profile

baldguy

9 posts in 26 days


#4 posted 08-23-2014 03:53 PM

ok, so I could actually just increase most of my tools to 4” and not hurt the airflow, then… that seems like a good option. I’d love to replace the duct on my TS since it always gets in the way of changing blades. I just need to find one that will fit, I guess.

So then it’s mainly the filtering issue that I need to worry about. I thought 30 micron seemed pretty sub-standard. Had I done more research I might have passed on the bundle deal, but I effectively only paid $100 for this one so it was hard to pass up. Impulse tool buying – anyone familiar with that problem? ;)

If I can pick up a filter for the top and a plastic bag (or can?) for the bottom then I’ll be in business. I’ll see what google has to say about part numbers and such.

View Fred Hargis's profile

Fred Hargis

1784 posts in 1147 days


#5 posted 08-23-2014 03:56 PM

You won’t be moving the same volume of air. A dc moves large volumes of air at low static pressures, the opposite of a vac. Increase the SP (reduction) and you reduce flow. Maybe a good place to just peruse some stuff would be the Bill Pentz site. Check the FAQ section first to avoid getting a headache from the techno-babble.

-- Our village hasn't lost it's idiot, we sent 'em to Washington.

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baldguy

9 posts in 26 days


#6 posted 08-23-2014 04:08 PM

thanks for that link. I’m fine with techno-babble, I deal with it all day at work :). This is different babble, but I think I can handle it.

so it sounds like what I really need is a separator and to replace the bags with a filter solution. I’m trying to find one that will fit. till I get it delivered, I’ll just be extra diligent with my respirator.

View GJK's profile

GJK

15 posts in 40 days


#7 posted 08-23-2014 04:44 PM

baldguy:

As SawDustJunkie said, get the HF 5 Micron and—like so many others—modify it with the Wynn to move to 0.5 micron. 30 Micron is indeed absurd in the save-the-lungs world!!! See my post for a series of modifictions to make the HF 2 HP 5 micron (a) more movable, (b) more sturdy, (c) better electrical, and (d) better filtration to 0.5 micron. Good luck and it’s worth overthinking dust collection for the sake of your lungs—don’t be like the coalminers of years past!!

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baldguy

9 posts in 26 days


#8 posted 08-23-2014 04:46 PM

Looks like the filter itself is more than the cost of just buying a HF one, especially with the sale going on right now and the 20% coupon for this month. and that DC is rated to 5 microns.

this might be insane… but I had a thought – why not enclose the shop fox DC in a plywood box that is sealed up well, and put some cheaper, replaceable filters in that box to vent? Lowes sells some rated to 0.3 micron that are 20×20, and a 2-pack is about $20. 2 of those on opposite walls of the theoretical enclosure should easily allow enough exhaust airflow, and I can swap them out quickly and painlessly. with the pre-separator I’d get the big stuff there, the smaller stuff in the bags, then the really tiny stuff would either settle in the box or get caught in the filters. Plus there should be some noise-reduction benefit…

Is that a dumb idea? Maybe a washable version of the same thing would be more reasonable? Maybe I’m just purely insane?

View sawdustjunkie's profile

sawdustjunkie

166 posts in 370 days


#9 posted 08-23-2014 04:55 PM

I think if you did that, you would have 2 problems!
1) you would probably overheat the system and 2) you would most likley starve the system for air which would burn out the motor.
I do like the idea of cheap furnace filters though.
The Wynn was $160 or so, but really works great.
What you paid for the collector and the jointer, you saved a bunch of money anyway.
The dust bags on the dust collectors are worthless.
I did see a post somewhere where a guy used 2 large diesel truck air filters for his system. I don’t remember if they were cheaper than using 1 Wynn filter though.

-- Steve: Franklin, WI

View Fred Hargis's profile

Fred Hargis

1784 posts in 1147 days


#10 posted 08-23-2014 05:12 PM

Don’t feel bad about getting your DC versus the HF. You almost certainly have an 11” impeller, the HF has a 10” one (big difference). I’m not (and don’t) poo-poo the HF, but you have what you have so move on. I would say the best way to avoid buying a filter would be to vent the unit to the outside…of course, if you have heating or cooling you may wish you had went ahead and bought the filter.

-- Our village hasn't lost it's idiot, we sent 'em to Washington.

View baldguy's profile

baldguy

9 posts in 26 days


#11 posted 08-23-2014 08:48 PM

i went by HF today to see if they had any DC parts on their sale list for this weekend. The DC itself was on there, but none of the parts are carried in the store. I walked out with a cart full of (very) cheap clamps that won’t last me a lifetime, but should be helpful for a while.

I was thinking that if I could get the 5 micron filter bag from the HF DC then I could set mine up like the HF one. But, it sounds like I really need to get even better filtration than that, so I guess I’m looking at a Wynn filter or some other solution. I do want to explore the furnace filter idea a bit more. Using 4 of them together shouldn’t restrict the airflow at all, since they each are supposed to allow over 1000 CFM, and the DC moves less than 4k. Just spitballing here, but it just might be a solution to the problem. Plus, I can use the same filters that I use for my home HVAC units, which I buy in bulk from a friend who owns an HVAC company. The question is probably going to be more about how long they last than how well they perform.

I’m at least willing to put this to the test. I did some searching on the ol’ interwebs and I see that the man over at woodgears.ca (who I would happily call a genius, given the things he has created and invented) is using the same 20×25x4 filters I use at home in his shop DC and filtration setup: http://woodgears.ca/dust_collector/v1.html – if he can make it work, I might be able to swing it, too.

As for the motor overheating, I don’t think it would be an issue given the volume of air that will be constantly circulating inside of the box. If it does get too hot, I think I could solve that just by moving the motor to the outside of the box. I’d lose most of any real sound dampening that the box provided, but loud is better than hot :).

Anwyay, I definitely appreciate the feedback. You guys have convinced me to move to 4” ports on the tools as much as possible and to add some good filtration to the DC and an air cleaner to the room. One of the things that draws me to woodworking is the concept of building things that serve purposes. Even if I build it and it doesn’t work like I want it to, I’m sure I will learn something in the process and have fun doing it.

View baldguy's profile

baldguy

9 posts in 26 days


#12 posted 08-23-2014 09:38 PM

one other thing I found, from watching some of mattias’ videos, was this Big Horn 1 micron filter bag:

http://www.amazon.com/Big-Horn-11765-Diameter-1-Micron/dp/B001C04FJY

There are several options of varying price like this… I might just use these for a while and see how that goes. haven’t decided yet, still trying to come up with more ideas that don’t cost me another $175 :)

View ncdon's profile

ncdon

146 posts in 1529 days


#13 posted 08-24-2014 11:17 AM

Here s another link for a low mic bag.http://www.highlandwoodworking.com/shakerfeltpolyestermicronfilterbag20x32.aspx

-- Don, North Carolina,http://www.ncdon.com Working full time at retired.

View jimmyhopps's profile

jimmyhopps

139 posts in 1032 days


#14 posted 09-05-2014 02:44 PM

you can also skip the bag entirely and vent the DC through a wall to the outside. that is what I did and works great. and this actually makes it work better by lowering the static pressure / resistance of the unit.
you can also buy a dedicated air filtration device, but they are expensive and take up space.

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