Filters for Air Filtration Unit?

[Tom Andersen]

Hi friends,
I just got hold of fine squirrel cage fan and plan to build an Air Filtration Unit. What is the best place for buying filters on the Internet? I suspect that I will need a prefilter, a 5 micron filter and a 1 micron filter, all about 25"*15" in size. Can you get a washable 1 micron filter?
Tom

[Tim Johnson]

I am using a common size of household furnace filter that I can get at the local hardware store. There are the special allergy, 1 micron filters that cost a bit more than the cheap, blue ones that are common here in the states. I would check to see what you can get locally for a reasonable price and then adjust your air filter plans accordingly. The home filters with the same stated filter size seem to work as well as the "special woodworking filters".

Has really helped cut down on the fine, suspended dust in the shop that seems to hang in the air forever, until you apply a coat of finish to something.

[Bartee Lamar]

I just finished building a Air Filter.

I am SURE I spent more doing it myself, but I had fun.

I purchased a 450 CFM 220VAC KOOLTRONIC DUAL ENCLOSED BLOWER (http://surpluscenter.com/item.asp?UID=2006081315565128&item=16-1154&catname=electric) from SurplusCenter.com

I designed the Airfilter around 12x24" filters. I purchased a ASHRE 65 12"x24"x18"deep (http://www.pennstateind.com/store/ac65f.html) From PennStateInd.com.

I use 3 filters. the first filter is a cheap blue mesh filter from HD. This is intented to get the big stuff and replaced often.

The 2nd filter is an 3M Filtrete (http://www.3m.com/us/home_leisure/filtrete/412_micro.html) . I do not intend on replacing this very often.

The final filter is the Penn State very expensive, very effective filter.

My only complaint is it is noisey. Someday I intend on installed a real DC and will build a room around it. I will move the Air filter into that room.

The whole box is about 12x24x34. It is was overengineered and very heavy. My is hanging from the ceiling. It is no easy trick to get it 8 ft. ovehead by myself.

A lot of people have built various forms of these. I am sure you will get more replies and suggestions.

Good Luck.

[glenn bradley]

I also modeled mine around what was available locally.

[Russ Massery]

I built mine from a set of plans from woodsmith. Instead of using a series of filters. I found a bag filter that the commerial units use. I found them at http://www.grainger.com

[Bruce Wrenn]

Surprisingly the finer filter will rapidly stop up. It is doing what it is supposed to though. Bag filter can be vacummed out using shop vac with a piece of pvc pipe with 1/2" holes bored in it. I use the cheaper pleated filters from Lowes/ HD along with a bag filter from Grainger. Bag filter is still original, while pleated filter is regularly replaced. My blower wheel is a 10" model from surplus (junk) along with 12X24 bag and pleated filter. I figure that every thing that air filter catches, my lungs don't.

[Steve Roxberg]

Buy the filters before you build the box. I have a really good friend who didn't do that only to find out that the filters wouldn't fit. My friend :o was upset and had to modify a few things.

[Al Willits]

fwiw, I stick with readily availible filters to keep replacement availibility and cost down, maybe use the Honeywell Electronic Air cleaner metal mesh pre filters as the first filter, they're washable and should last a long time.
Then maybe a standard $.99 plain jane 1" as a second filter, then one of the Honeywell/whatever 1" pleated filters as the last filter.

You can also use a 4" pleated filter like the filter cartridge that replaces the electronic cells in a EAC that Honeywell sells, for even more filtration.

Try to stick with basic filter sizes if you can, 16x20 or 16x25 are two very common sizes.

I'd try to keep it as basic as I could...remember K.I.S.S....:)

Al

[Tom Andersen]

Two more questions before I buy the filters:

1) I appears that there are two types of 1 micron filters: Bag filters and pleated filters. What are the selection criteria?

2) I found filters from Grainger that seem fine for my purpose. Apparently they don't sell to individual persons? Any way to circumvent that?

Thanks-

Tom