Connecting a Sander to a Dust Collector

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Forum topic by qball posted 06-13-2012 02:36 PM 2792 views 0 times favorited 10 replies Add to Favorites Watch
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49 posts in 3088 days

06-13-2012 02:36 PM

Topic tags/keywords: sander dust collector fittings dust right 4 2 12

I am trying to hook up my dewalt sander to my harbor freight dust collector. The connection is as follows:

fitting that connects to the sander with 2 ½”
2 ½” hose
2 ½” to 4” fitting
4” dust right handle connected to 4” hose
All this connected to the dust collector

The problem is that when I hook up the smaller hose the dust collector seems to bog down and the suction goes away. The chips even stop spinning In the collection bag. Is this approach even possible? If not what’s the best method for dust collection for a sander?

10 replies so far

View jmos's profile


823 posts in 2331 days

#1 posted 06-13-2012 03:18 PM

The 2.5” hose really chokes down the flow. DC’s move a lot of air but don’t have tremendous suction. An easy answer would be to use your shop vac for DC with the sander. Shop vacs move less air but have greater suction. In addition, if you have a HEPA filter in your shop vac it will trap more of the really fine dust that sander like to create. It would also help to minimize the length of the 2.5” hose, the longer it is the more resistance.

You could try an experiment, I don’t think it will help, but it might, and it’s easy to try; open up more ‘area’ to the DC and see if that helps (second 2.5” hose, second 4” hose). It should lower the suction, but if you’re really choking off the impeller it might help.

-- John

View crank49's profile


4030 posts in 2933 days

#2 posted 06-13-2012 04:30 PM

Don’t worry about “choking” the dust collector.
Restricted flow causes no harm.
In fact, restrictions only cause reduced power draw by the motor and a slight increase in RPM.

I keep a 2 1/2” hose connected to one side of the “Wye” connector on my HF collector and a 4” on the other. It will handle both of those connection being open at the same time.

View jmos's profile


823 posts in 2331 days

#3 posted 06-13-2012 04:48 PM

Michael, perhaps ‘choking’ wasn’t the best choice of words, but at the system resistance increases the fan is pushed back on its curve and the flow drops. qball is clearly describing a serious drop in flow. No doubt it will not hurt the DC (blocked inlet will be the minimum draw on the motor), but it doesn’t help him suck up dust from his sander.

Opening up a second hose, as we both suggested, will increase flow through the fan, and may improve his performance with the sander. I don’t have a HF DC, or a copy of the fan curve, so I can’t say for certain.

-- John

View crank49's profile


4030 posts in 2933 days

#4 posted 06-13-2012 05:01 PM

It’s a common thing for most folks to think the motor is straining when the flow is restricted. Just wanted to offer a little clarification.

It might be worth noting that the same thing is not true for some shop vacuums.
Many vacuums depend on air flow through the system to cool the motor.
Not all, some have separate cooling flow, but the ones that don’t will fry the motor if operated with restricted flow.

View lumberjoe's profile


2899 posts in 2210 days

#5 posted 06-13-2012 05:16 PM

I use this and it works awesome!

Here is the link
It’s 30$ from harbor freight. The hose fits directly into the dust port on my RO sanders without adapters. You can use this vac with bags. While not as good as a hepa filter, I don’t get any noticeable dust blowing out

This vacuum is terrible for anything else, but for sanding it is awesome. It’s very small, very light, and plenty powerful enough. After sanding the only dust left behind needs to be picked up with a tack cloth. If you wipe your hand over the piece it will be clean.

Also I’m not convinced HEPA filters on home owner shop vacs are any better than using bags. I have yet to see a home owner shop vac pass an EPA HEPA test.


View qball's profile


49 posts in 3088 days

#6 posted 06-13-2012 05:25 PM

I’m gonna try to open the closed port on the wye and see what happens. If that doesn’t work then I guess I’ll have to hook up the shop vac. I’l let you all know what happens. Thanks for the input.

View Loren's profile


10241 posts in 3610 days

#7 posted 06-13-2012 06:51 PM

I used a vacuum hose on my DC and the suction was
unimpressive. The DC sucks great at 4” but when stepped
down to less than 2” it was less effective than an ordinary
shop vacuum.

View Fred Hargis's profile (online now)

Fred Hargis

4943 posts in 2455 days

#8 posted 06-13-2012 07:49 PM

The shop vac is going to work a lot better…be warned, what you will be sucking is the finest of dust particles. You may need a tighter filter (or drywall bags) on your vac to keep from distributing those particles back into the shop air. I put a Gore Clean Stream on mine just for that reason.

-- Our village hasn't lost it's idiot, he was elected to congress.

View qball's profile


49 posts in 3088 days

#9 posted 06-18-2012 07:14 PM

Ok I tried opening up the wye on the dust collector and it kept the dust collector from bogging down however the suction threw the small 2 ½” hose was very low. I hooked it up to the shop vac and wow what a difference. I guess I found my answer.

One more thing, do I not need to worry about burring up the shop vac with all the dust and continued use?

View Murdock's profile


128 posts in 2446 days

#10 posted 06-18-2012 07:22 PM

If you have a decent filter in your vac and occasionally turn it off to cool (especially if it is feeling warm) then you shouldn’t have an issue.

I have done some extended sanding sessions with my vac (shop-vac brand) without any issues. I have upgraded the filter with a HEPA one as others have suggested. I don’t use a per-separator but I do use the bags even with the HEPA. I know a lot of people feel it is overkill, but I like how easy it is to empty the vac and it acts as a pre-filter for the HEPA.

-- "Anyone who has never made a mistake has never tried anything new." - Albert Einstein

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