Exhaust fan question

J

J. MacDonald

Joined
Jun 8, 2000
Messages
3,140
I probably should have done more research on this before getting this far into my shop project, but sometimes life is a bit of a learning curve. My little shop is aprox. 12'x 14'x 8.5' with a
2'x 2' soffit at one end as I still needed to be able to open my garage door. I figure this gives me about 1400 cubic feet of air, minus of course the machinery and cabinets and such.

I had my electrician install a 110CFM squirrel cage exhaust fan in the cieling while he was up there, vented to the outside through 4" dryer duct tube. By my math this should give me a complete air exchange about every eleven or twelve minutes. Is this enough airflow for a safe shop?

Obviously this system won't move enough air to act as a dust collector, so a respirator will be required when grinding micarta, CF and the like, but will this fan move enough air to keep harmful fumes at bay?

I look forward to your opinions.

John
 
A knifemaker I knew had an attic fan set between the studs in a wall, behind his grinder. Nothing at all grew in his yard, in the vent path of that fan. Yet his kids were playing in it. :eek:

The fan will not take the place of a respirator, but without a filter on it, toxic dust will be dumped outside.

You might want to look at one of those ceiling mount air cleaner setups. I saw one in a Harbor Freight catalog for about $150-160. They would remove particules from the shop, and trap them for proper disposal. But you should still wear a respirator.

The type of system where you can remove particules, and gasses, without contaminating the neighborhood, and maybe get by without a respirator, are heavy duty vacuum systems with filters, fire/spark traps etc. They can run upwards of $2500-3500. :eek: :D
 
Mike, thanks for the advice. I had figured on rigging some kind of filter on the fan to keep particulate matter from building up in the exhaust tubing....er...I mean, to keep from poluting the neighborhood. It's only a hobby shop at this stage and I wouldn't even consider myself a maker so there's no steady output of anything yet (products or byproducts). I'll have to look into that HF thing, it sounds like it might be something I'd consider.

Thanks,,

John
 
John, Since dust control is also an issue in woodshops, some of the woodworking magazines and websites have plans to help you make your own air cleaner that traps the dust particles in filters and baffles.

Tip: pantyhose make good pre-filters to catch most of the chips and some of the bigger dust chunks.

Here's step-by-step info on how one ceiling air filter got built:
http://www.geocities.com/drvermin/Overheadfilter/airfilter.html

Below are some other links with info or pics of cleaners that you may be able to get ideas from on how you'd like to build your own air cleaner. The minimum units are made of only three parts: box, fan, and filters. On some of them, you may need to adapt it to ceiling-mount instead of having it on the floor, wall, etc.
http://www.woodworkersworkshop.com/plansshare/air_filter_downdraft_sanding_table.htm
http://www.ronan.net/~woodwork/airfilter.htm
http://wood.bigelowsite.com/air_filter/
http://www.hal-pc.org/~billv/picdir/filter1.jpg
http://www.shoptours.org/member2/rg-airfilter.jpg linked from this page
http://www.rockslide.org/Images/dfilter1.jpg linked from this page
 
Do a search on dust removers. There was 1 homemade that used 12x20 furnace filters stacked in a box drawing air through them and blowing it out the other side.
I made it and set it up to blow clean air down over my grinder.
not pretty but works pretty good.
Take Care
TJ

Thats the one rokjok has it
 
I am glad this came up. I have wanted to build one of these for a while, one for my wood shop and one for my grinding room, but when I did a price breakdown, it ended up being much cheaper to purchase one at around $180-210. I haven't purchased one yet, but really am curious how you folks that have made one do it economically. I priced appropriate blowers (~450-600 CFM) in my catalogs at $160-200+, which just isn't worth it. I keep looking for used ones but haven't had any luck yet. They usually are huge furnace blowers or little bitty jobs that push 100 CFM.
Are you guys using second hand blowers in these filters? Where are you finding them?
Thanks,
Brome
 
go to any ac shop and ask them for a blower out of an old furnace try to get one that has just been replaced so you will know that it has not been sitting outside and got wet i am an installer so i pull the ones i want as soon as i remove them from the house you can also find 1\2hp to3hp motors in pakage units that are good for grinders and buffers
 
You must log in or register to reply here.
Back
Top