Shop air filtration?

charlz · Dec 13, 2009

This time of year when I have to close up the shop to keep the heat in air quality in my small shop starts to be an issue. Plasma cutting, welding, grinding etc etc

I was wondering if anyone has experience running something like this in a 'metal' shop?

Amazon.com: JET 708620B AFS-1000B 550/702/1044 CFM 3-Speed Air Filtration System with Remote and Electrostatic Pre-Filter: Home Improvement

I've taken to wearing a N95 dust mask while working but I wouldn't mind if everything in the place didn't develop the same 'patina'

I usually crack a window and the door going to the unfinished and vented upstairs and the movement of heat moves most of the fumes but doesn't seem to affect the really fine dust much.

SPIKER · Dec 13, 2009

back about 15 years ago we built a lot of these for a company, they work rather well not much to them but for plasma dust/smoke the filters need to have the higher grade lower dust particulate size filters installed. of even HEPA filters. the filters will require changing often if the air is very dirty but it is better than the dirt in the lungs... The one you posted looks like a near ripoff of ones we built way back then...

Mark

Redneck in training · Dec 13, 2009

If the shop is small and heat cost is not big issue (in ex heated by a wood stove) you will be better off with heat exchanger ventilation. It will blow polluted air out and bring clean fresh air in. The air exiting the shop will preheat the air coming in. I have similar system for my whole house but the volume it exchanges is relatively small because it is designed for continuous operation. My unit also filters air but that you don't need for a shop.

Product Detail
Home Tips : Heat Recovery Ventilator (HRV) Buying Guide

Google "heat recovery ventilation" or "energy recovery ventilation"

jimgerken · Dec 15, 2009

Charlz: What works well for me is a home-made down-draft table under the plasma. It doesnt need much CFM if you can collect it RIGHT at the source. I probably move 400 or so CFM with a blower I got out of a floor-cleaning machine. Less CFM removed from your shop reduces your heat loss of course. I use the table for spray painting too, and if the project is small I can paint and really not even smell the fumes. I have plumbed the same blower inlet thru a "Y" and a couple blast gates to the area of the grinder and sander, but have not completed that pickup yet. A pickup that you could move around a little, say on a big flexi hose of some sort, could also work for welding. Collection at the source and pump it out of the shop, lots more effective than allowing the whole volume of air to get polluted and then gradually filter it out. BTW, I own the Jet unit you are looking at, its mounted on my shop ceiling, and I use it. But it would be very slow in cleaning up the air if I allowed it to get polluted (without the downdraft table).

charlz · Dec 17, 2009

Thanks for the ideas guys. The downdraft table sounds interesting... except my shop is so small I work on sawhorses when I need to do metal stuff so it can be broken down and moved out of the way when not in use

Maybe I can figure out how to build a 'break down' version.

I am thinking of making a small 'paint room' upstairs and the down draft table is a great idea for the paint table versus just venting the room.

Gary Fowler · Dec 17, 2009

You could build some portable funnel type fume gathers about 12" in diameter that you could position over your welding operation from a portable stand. Hook the funnel to the hose on a shop vacuum and use it to suck up the fumes and dust. The exhaust air could just be dumped out via another flex hose attached to the discharge side. The standard shop filter would likely not trap the smoke, but would take care of larger particles. Just dont let the enviromentalist police find that your dont have a sub-micron filter system on the smoke you are exhausting.

steveoutdoorrec · Dec 25, 2009

When I worked in a factory as a painter we used downdraft tables for sanding and painting small parts. The welding department next door used them too. Worked great but with a small shop there just isn't room.

What I'm thinking of doing in my shop is making a small table that folds up onto the wall when not in use. Instead of one big suction pipe at the bottom I'm thinking a grid of pipes with 1" or larger holes around the bottom. This should keep the suction level up in all areas of the box. Ideally it should have fold out sides and easy to attach legs for support.

For larger jobs I'll still have to open the garage door and weld fast to keep the heat in but a little cool air is better then breathing smoke and grit.

markct · Dec 25, 2009

well after years or welding outdoors i finaly wanted a place to be outa the snow and rain for the small and medium size welding projects. we have a 20 ft by 25 foot or so garage that has the machine tools and such in it, but its just too dangerous to weld or grind in there due to the construction of the building and the clutter and stuff in there, i would be very affraid of fire. so my solution a few months back was to take and build a lean to on the front of the building, just a simple 8 by 12 ft pole barn type shed, open in the front. i put my 700lbs welding bench in one corner and a small metal table to set the chop saw on, has a light duty chain hoist on a trolley on the ceiling. it works great and is open enough that the air circulates out doesnt get too smokey. i do have a tarp i roll down on the front sometimes that keeps the wind out but still thru the open walk thru doorway a good bit of air ventilates. it simply wouldnt be practicle to try and weldin in an enclosed area especialy when doing heavy oxy cutting or air arc gouging as i sometimes need to do. hanging from the ceiling i have a 1300 watt radiant heater. it doesnt make the place warm like the house but it takes the chill off so your can work without your fingers being frozen and helps some with keeping the welding helmet from fogging in winter

DJ54 · Dec 25, 2009

Jim,
Can you post some pics of that welding downdraft table? Sounds like that would be the ticket in my shop, for smaller projects.

I'll be moving next summer, and giving up my dream shop. So I'll be laying out "Dream Shop II" this winter. Probably be going 40' X40' and minumum 12' to the square.

Thinking of devoting one corner near one of the overhead doors for the welding equipment.

The downdraft table, plus an overhead hood, or something similar, maybe something portable would be the berries.

Not that concerned with heat loss, as I'll have a dual heat system. I'll get the old coal furnace out of my old shop on the property, and let my waste oil furnace supplement it on days I'm not working in the shop.