Air Cleaners

[jackellis]

I know there have been many posts on this subject (I've read most of them here and on Sawmill Creek) but I'm still interested in opinions.

I have one that sits on the floor and doubles as a planer stand. It's on the floor because there's no good place to hang it in a garage shop that's open to the roof. However in the new house, my shop will have a 7' 6" ceiling and I have a spare furnace blower set aside.

I'm considering a design in which the air cleaner is attached to a wall just below ceiling height and near a power outlet using a French cleat (easy removal). It won't be over the table saw but it will be over the wall where most other stationary tools are parked and also near where they will be used.

In addition to an intake at one end and an outlet on the opposite end, I'm trying to decide whether to have additional filters on the side and bottom at the intake end to increase the amount of filter surface and slow the flow of air through the intake. I'm not sure it makes much difference other than to lengthen the interval between filter changes.

As with version 1, I'm going to use three filters - a coarse fiberglass filter outside filter to keep the progressively finer ones behind it from being clogged with large particles, a finer filter in the middle and a high quality filter inside.

Any opinions or pointers to research on whether having the air cleaner close to a wall is going to make a material difference in effectiveness?

Any opinions on whether having more intake area is going to make much difference in effectiveness?

Any opinions (and recommendations) on whether washable filters make sense, especially for the inners that can be expensive to replace all the time?

[poolhound]

Jack,

Thanks for posting. I have had a blower moter sitting around for a year now with the intent of doing something similar and have been considering similar questions.

I was also thinking of building mine into a base that could double as a downdraft table.

[master53yoda]

The ones I have built use a 20x20 or 20x25 filter size. I use a 1" low end pleated filter in front of a 4" pleated filter. This filter size is acceptable for a fan that moves no more then 1200 CFM If the fan moves more then that you would need a larger filter area. If you don't know how much air your fan motor will deliver you could look up the blower wheel size that you have on WWgraingers site and check Your external static pressure on that assembly with those filters will be approximatly .75" water column. I use a u-tube monomiter to identify when i need to change the filters. I have used this assembly both as a wall or cieling mounted but currently mine is the base for my Bt.

I have also used them for sanding tables by looping the air flow so that as much dust drops to the bottm before going through the filter to extend the filter life, intial the loop has a door that can be opened to remove the dust from the lower chamber

[poolhound]

I have also used them for sanding tables by looping the air flow so that as much dust drops to the bottm before going through the filter to extend the filter life, intial the loop has a door that can be opened to remove the dust from the lower chamber

Sounds interesting. Got any pics?

[jackellis]

Sounds interesting. Got any pics?

I'd like to see that too. If you can get the air slowed down enough a lot of the coarser dust particles will simply fall out. Have the bottom slope like a funnel into a 2 or 3 inch opening that then drops dust into another chamber and you should be good. Just like the cyclone DCs.

[master53yoda]

I'm finishing up a crib right now but building myself a sanding table is the next project on my list. I'll find the drawings on the last one I built and post them in the next couple days. I've built them for other people but never got around to building one for myself until now.

[LinuxRandal]

Since your moving shop, as long as you have your other one, could you set it up as a downdraft/outfeed table and planer stand? Then you run it whenever needed, and the wall one would get the secondary dust, and not get as much gunk. Then you should only be replacing the outside one or two filters, and the expensive inner filter, would last a lot longer.

[Tom Slick]

To make it the most effective you should have it exhaust on the other side of the shop pointing toward the intake. blowing dust toward a filter is much more effective then sucking dust toward a filter. most people don't think about cross-flow.

The bigger the filter the better. check with your local autobody supply for bulk prefilter material, it may be cheaper than replacing "cheap" glass filters.