Want to make a home made air scrubber

[owler]

My shop is in the basement and even though I have a dust collecting system for the larger tools, there is still a lot of air borne dust. Of course the scroll saw is a major contributer.
I want to build a ceiling mounted air scrubber that I can turn on and off with the shop lights. I thought about using an old furnace blower. I think the blower should move a lot of air. Has anyone tried this and have any advice?

I am also wondering what kind of filters I should use. I'm not sure if regular furnace filters would trap the smaller particles and I think a HEPA filter would trap too much and need cleaning constantly.

I thought about using both, the furnace filters externally and a HEPA filter internally, but I am also concerned about restricting the airflow too much and burning out the motor.

Any advice would be appreciated.

[William Young (SE BC)]

owler;
I built mine for about 1/4 the cost of a manufactureed one with the same specifications of cfm and cubic ft of air to be cleaned etc.. The used blower is one with the motor installed in the center of the squirel cage. That saves a lot of space and weight compared to a separate belt powered blower and motor. It is shown sitting on my scrollsaw stool previous to installing it.
It is best to get all the parts together before building the box so you can build the size to suit the dimensions of the parts.
Ordinary furnace filters are good only for primary ones for catching the bigger particles but for catching the real fine and most dangerous dust you need a felt pocket filter as shown. It is made of the same material as the felt bags in the better DC systems.
The box is plywood and just basic carpentry and the pocket filter cost approx $40.00.
I have it hanging on chains from the ceiling and you would be amazed how much dust it collects in both the primary and secondary filters. The filters are 16 x 20 in mine but you can build it any size you want depending on the size of pocket filter you order.
I have it connected to my shop lighting circuit so it comes on and runs continuously as long as I am in the shop and it goes off when I leave and turn out the lights.
I put a switch in line with the power cord so I can turn it off for cleaning the filters.
It has been going strong for 4 years now and has been trouble free.
Hope this is of some help to you.
W.Y.

[boogatoo]

Use a blower or fan with conduit outside.

Air filter are part of the solution but also part of the problem.

In my previous house I connected the fan to a conduit connected to an exhaust trap (like the ones used for the clothes dryer and bathroom fans). I ran the conduit in between the ceiling joist and made a round hole in the aluminium siding of the house. The exhaust trap type I connected is the one with a bird guard. Put caulking around the trap so rain water does not infiltrate into the wall. If you go for this solution, you should use a strait pipe conduit that has a size is suitable with the CFM of your fan or blower (don't use flexible accordeon pipe type). In cold area (like CANADA where I live, use isolated conduits and install it with a tiny slope so moist due to condensation (contrast between hot air from inside to cold air from outside) drip outside. That is a cheap solution and you don't even have to think of the filter replacement. This also remove smell from varnish and paint, filter does not. It also remove burnt smell I might sometimes make that on my table saw.

One more thing, filter systms do indeed filter dust on the input side but the output it shake the air and therefore create airborn dust that your lungs will inhalt. My solution does not.

[owler]

William,

I am happy you verified my idea would work. I like the felt pocket filter. I don't remember seing them in Home Depot or Lowes. Where did you get yours?

Boogatoo,

It won't be easy to get the exhaust outside through the wall. I have already run a few electrical and speaker lines outside and my wife has never been keen on the idea of me putting more "holes" in the siding.


I don't have a blower motor handy but I have seen several very cheap on ebay.

Thanks!

[William Young (SE BC)]

Dan;
I got my pocket filter from http://www.busybeetools.com/
in Canada . I notice that they don't have my particular size any more but they have a replacement filter for the B0255 air cleaner which is 24x12x30. I don't know if the filter is 12x30 or 12x24. They only show the back with the exhaust port.This is why I say get your parts before building the box. The filter # for that one is B-2055F2 for $69.00 but they put them on sale at greatly reduced price sometimes.
They filter 98% of dust down to one micron which is close to negligable as far as dust particles go. And as it forms a "cake" on the inside they filter down even lower. That type of filter should never be blown out with compressed air. Just remove it and shake it outdoors or inside a large plastic size garbage bag and replace it in the unit. I still wear a very high quality dust mask to catch any local dust in the air from sanding before it reaches the filter.
In that site click on products. Then in the search box type in air filters and the ones mentioned above will come up.
You could also check all the major tool suppliers for overhead air filters and the replacement pocket filters for them.
An air exhaust to outdoors system is just not an option for me living in Canada. The cost of the loss of heat would prohibitive because I like to work in a comfortably warm shop instead of a cold one. And to exhaust the air along with the heat to the outdoors you create a vacuum meaning that somewhere you have to have air coming in to exhaust air going out unless it is of a size that is practically useless to start with. Summer time is a different story. Draw air in one side and blow it out the other is just fine. I do that with a 20" box fan in a window blowing out and another window or even the door open. .
But I still have my air cleaner running all the time that my lights are on. Can't get too much clean air.
W.Y.

[owler]

I am working on aquiring a furnace blower on ebay.

My shop is pretty square. I am considering putting a distribution box on the back-end of the scrubber and putting four outlets to send a vent to each corner of the shop. I would then hang the unit in the center. I think that would work pretty well.

[William Young (SE BC)]

Dan;
Th most accepted way of hanging any air flter is to install it up close to the ceiling about central to one side wall of the shop and close in to the wall. (within a foot or so). That way the air will circulate out of the back of the unit and make a trip all around the other sidewalls and return back into the intake of the filter.
I was told to do that from someone on another site and sure enough I can hold a kleenex up and follow the path of forced air all around the shop from output back to intake.
If you try another method, be sure to let us know if it works as efficiently as I have just described.
Have fun knowing the satisfaction of building your own and knowing that it will work as good or better than some of the commercial ones and that you have saved a bunch of money by doing it yourself.
W.Y.