# Exhaust Fan Idea



## Evilsports (Nov 17, 2020)

Hi folks.

I do my working in my half of our 2 car garage. I use a shop vac for dust extraction, which means I end up doing all of my sanding and table saw work either outside in the summer or in the shop at work.

I picked up a new 3/4hp electric motor a few months back to use on a drum sander project that I've since decided is not necessary.

I was wondering if any of you have made your own exhaust fan to vent fine particulate out of your work space?

I'm curious if it might be a solution that enables me to sand/cut in the garage without having that fine dust settle over everything.

Could anyone who's tried this comment as to how effective it was? Did you put in an intake vent on the opposite side of the shop? Do you notice much heat loss?

Thanks for any advice.

Kevin.


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## CaptainKlutz (Apr 23, 2014)

Find dust collection needs to happen at source. 
Is very inefficient collecting it once it is floating in shop, and you will never stop dust landing on flat surfaces..

There are massive number of threads on dust collection here on LJ, and the WWW. 
All of you questions can be answered with some searching.

example solutions:

If you want to vent the air from shop consider using an attic or gable mounted exhaust fan in wall of shop. Generally move over 1200cfm, and are great for removing ALL of your expensive heated/cooled shop air to great outdoors once every 10-15 minutes. :-(0) 
IE Outside venting for dust collection is never a good idea with HVAC conditioned shop space.

For sanding dust, consider buying or building a down draft table.
Pretty simple, get a used furnace blower, stack of 1" filters, mount below a table with 1" holes drilled into it. Do all your sanding on top of table, and one problem is solved.

Best Luck.


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## bigJohninvegas (May 25, 2014)

I have tried things like a box fan stuck in the doorway of my garage. 
Never really worked for me, and never tried a real exhaust fan. 
I have climate controlled shop now, and so venting outside is not desirable for me. 
So many of us are using something similar to this air filter linked here. 
https://www.amazon.com/708620B-AFS-1000B-Filtration-Electrostatic-Pre-Filter/dp/B00004R9LO
I have this jet, but there are many brands at different prices to choose from. 
And you can make you own too. Here are the plans to the home made filter I started with. 
https://documentcloud.adobe.com/link/review?uri=urn:aaid:scds:US:07f7b7d1-f385-470a-9677-7bcbab075ba3

Home made filter I started with, 









And the jet I have today,








Nothing is going to keep all the fines away. But both the filters shown above work very well. 
When running a finish sander, I used to frequently forget to turn on one of these filters. I have gotten much better at that now, but anyway, shop would get cloudy fast. Turn on the filter and in a matter of minutes it was nice a clear. Now I do much better at tuning on the filter, and I never see dust in the air anymore.


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## Evilsports (Nov 17, 2020)

Thanks fella's. I had seen the downdraft table mentioned in a search I did, but was unsure what it was. It sounds like a better sollution. Likewise with the filtration system.


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## tvrgeek (Nov 19, 2013)

I too built a cleaner from an old furnace fan. I have HVAC, so I don't exhaust outside except when I make toxic fumes. I have a 14 inch through wall fan for that. Do my nasty work, turn on the fan and leave before I take my respirator off. Within half an hour, good to go.

Going to build a downdraft table as I have a 5 HP Clearview on order.


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## Evilsports (Nov 17, 2020)

Do you guys thing that the 3/4 hp motor I bought would be sufficient to power a blower on a downdraft table? I'm trying to decide if I can still use it or if I'm selling it to a buddy who wants it.

Thanks again,
Kevin.


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## kelvancra (May 4, 2010)

Looking at the commercially sold units, they are HIGHLY inefficient. They have no back, sides or top. My homemade one does, forcing all the air to come from where I am sitting. Laying my arms on the table, I can feel the vacuum tugging at my arm hairs (have to look down to make sure it's not a Pacific Northwet tarantula or some kind of swamp creature sneaking out of the surface top.

Adding a back, top and sides works so well I do my small routering projects in my sanding station.

I doubt a little shop vac would work as well as even a 1-1/2 horse dust collector. The furnace squirrel cage should move FAR more air than a vac. I'd just make filter room sufficient to add pre-filters, then use filters I could blow out and reuse.

SIDE NOTE: My top, back and sides are nylon, so I can sneak long boards and things through a side or back, when I have to.



> For sanding dust, consider buying or building a down draft table.
> Pretty simple, get a used furnace blower, stack of 1" filters, mount below a table with 1" holes drilled into it. Do all your sanding on top of table, and one problem is solved.
> 
> Best Luck.
> ...


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## GT350 (Dec 22, 2012)

I built the Wood Magazine Cyclone Dust Collector that they published in their magazines idea shop several years ago which works well for the stationary machines including the table saw. I had a Craftsman contractor saw that I built a cabinet for and with that dust collector it worked great. As far as the sander is concerned I have tried several ways to remove the dust and the best I have ever found is the Festool sander along with their vac. They are expensive but the first time I tried it I cleaned my shop first then sanded for about 45 minutes and there was no sawdust on any surface. Don't forget if you are serious about dust collection to get or build at least one of the dust collectors that hang from the ceiling.


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## rwe2156 (May 7, 2014)

IMO you're better off with a well made sander and dust extractor than I downdraft.

I've never understood them and would never use one. Small parts maybe but how is a downdraft going to collect the middle if a 3×5 foot panel other than sucking dust out of the air.

Plus, now you have a space occupying object that's becomes another "horizontal surface" IOW covered with crap.


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## kelvancra (May 4, 2010)

My down draft table is one of the most used stationary tools in my shop. With sides, back and top, it even trumps my Festool sanders. In fact, I, often, use them in the sand station when I'm doing items that require me to do round-overs, sand with much of the disks off the item and so on. In those situations, all the money dumped into a Festool sander and vac won't catch everything.

Of course, it's also nice if you do things like Dremel/Foredom work too. My Foredom, with an aggressive carving bit, throws off a lot of dust. The station captures every bit of it.

Again, key to efficiency is adding the sides, top and back. I show friends how I can sand a board just outside the station and everything falls off the disk in a curve and heads straight for the station.

Of course, a good sanding station does not do much to extend the life of the sanding disks, while a vac on the sander makes an easily seen improvement on disk life, since they don't load nearly as much.

I should note, I built a manometer to monitor filter condition on my home HVAC system. I liked it so much I went with a Dwyer magnahelic gauge.

Using the manometer or the gauge is very informative, and very telling as to the differences between the HVAC and a dust collector. The gauge I purchased (used) only goes to 25 psig (scale only goes to 1).

When I install a fresh, 5", MERV 11 filter in the unit, the gauge (positioned between the filter and the squire cage) reads .25. Two months in, and the gauge went up to .4, and you could hear the furnace ducting start to rumble, as the squirrel cage fought to pull air through.

Just for reference, MERV 8 filters from another company start out at about the same point as the better quality MERV 11 filter, so the source can make a big difference in filter quality.

Also noteworthy is, though the MERV 11 filters actually let more air through when initially installed, when the gauge climbed to 4, then, in a week 6, I can hold the filter up to the light and it doesn't look as if it's dirty and in need of

Anyway, taking the magnahelic gauge and manometer over to my dust collector, then merely holding the hose NEAR the opening, the draw pegged the gauge and started emptying the fluid from the manometer.


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## Ocelot (Mar 6, 2011)

Kelly,

I don't understand what you mean by "back, sides and top." How do you see the work and how do you reach it if it is completely enclosed in some kind of box. So, that must not be what you mean. Can you post a picture?

-Paul


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## kelvancra (May 4, 2010)

It's this simple (of course, it can be as pretty or ugly as you want it to be). The nylon just happened to be a piece I had laying around [from my R.E.I. days] and I didn't want to cut it and ruin it for other uses. It's been there about five years or so now, so, maybe, I should re-think that.

I added a foam pool noodle to the back rail so things resting on it don't get banged up by the low, solid back, as they stick through the nylon.

I like this beast so much, I'm thinking of making another, larger one. I could lay Masonite on the outer edges that aren't needed to focus draw to the center. Too, the bed would lift up from the front so you could retrieve that diamond bit that fell through more easily than popping the 4" hose off the back and reaching in.


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