Dust collection for metalworking

[Carlos]

Yes, I know this is a woodworking forum, but...I'm thinking about using our DC for metalworking. The idea hit me yesterday as I was sweeping metal shavings and dust from all over the shop, after spending the day cutting and grinding metal. I think since the DC has sealed bearings this should not be destructive. Comments?

[unknown poster]

Sawdust and grinding sparks can be a destructive mix, I wouldn't use a woodworking DS to collect grinding dust. I would also be concerned about all the extra air that my grinding sparks would be introduced too, this would probably heat things up and possibly create a fire risk.

When I was in welding school we had a grinding table with a mesh top and a fan that would suck all the grinding dust down into the table. I don't know what happened to the grinding debris after it left the table, you can't just blow the sparks outside.

I would look into the fume extractors they use for production welding, something like that is designed to suck up welding sparks without creating a fire hazard.

[Uncle Cracker]

When I was in welding school we had a grinding table with a mesh top and a fan that would suck all the grinding dust down into the table. I don't know what happened to the grinding debris after it left the table, you can't just blow the sparks outside.

That's called a downdraft table. Many of them have a collection bin built in underneath.

With regard to running metal shavings through a DC, one of my neighbors did, and he ended up with a whole bunch of them stuck permanently in his fabric DC bag. The shavings are heavier than sawdust, though, so I think a vortex chip collector can or cyclone DC would handle them. As for me, I just use a shop-vac with a disposable filter bag over the paper element, and relegate my DC to wood shavings only.

[Tom Slick]

I have reserched DC for metal grindings and there is no small cheap answer. Fire hazard becomes a real issue as does the fact that almost any type of filter media becomes clogged easily by metal. if you grind any aluminum then explosion hazard becomes the issue.

A standard downdraft table for welding doesn't have filters, it is only there to extract the fumes. to get into real grinding dust collection you get into several thousand $$$$$ machines to do it safely.

your best bet it to contain your grindings to one area then vacuum them up when you are done. if you put of side shields or curtains on your bench you will contain much of your particles to a smaller area to clean.

[Jim Boyd]

When I worked in machine shops we used shovels and brooms.

[Carlos]

I guess I should have put the emphasis on cutting; the plasma cutter of course sprays nearly-vaporized metal dust everywhere. Griding is also messy, but nothing sprays the entire area like plasma cutting. I guess I could try putting a deep bottom on my plasma table and see if it catches the stuff. Or just go back to doing all my metalworking outside.

[reddog552]

Plazma table

Have you thought of a water bath under your table this will catch a lot of the metal,as far as smoke(and lots of it)i know of no cheap way out.Large luvered fans work best.Filters & ductwork are also not cheap.Do you have pics of your table.I have instaled a number of them.

[gad5264]

I work in a metal fabrication shop and we often polish 316 stainless steel for some of our customers. About a year ago we purchased one of these metal cyclone separators and to date have not had any problems with it.

http://cgi.ebay.com/Cyclone-Separato...QQcmdZViewItem

[Carlos]

Water...never thought of that, great idea. I could probably come up with a way to put a bin under it to hold water. I haven't had much smoke issue except when cutting something that had paint and sealer on it. That was obnoxious. I ran the air filter and that really helped.

Haven't taken any pics, it's simple and ugly. A 2' square frame made from 2" square tubing. Three cross braces from 1.5" L stock, and slots cut into the L stock for strips that will support the work. Those are flat strips 3" wide, just dropped into the slots, so I can flip/replace them as they get burned. For small hobby work this should work well. I do most of my cutting from the edge of the welding table, but I suppose I should rig up something like your water bath idea and use the plasma table instead.

Hey, got any pics of a good table that I can get ideas from?

[Carlos]

About a year ago we purchased one of these metal cyclone separators and to date have not had any problems with it.

Oh, ****, that's pretty nice. And I just finished building myself a simple separator, but this would be nicer.

I assume you guys only work with steel, not wood or aluminum? As others pointed out, I have the added issue of flammable/explosive wood dust in the system. I'm thinking a potential option is to make a small separator to put right by the metal tools, so it should catch all the metal stuff before it gets into the system.

[Tom Slick]

Aluminum is also explosive in dust form, especially if mixed with steel dust.

If you wanted to build a simple downdraft table that had a fan to pull the air/fumes/particulates toward the water it would be fairly effective and less chance of fire/explosion.
A metal grinding downdraft table pulls the air though a water bath to filter and catch the particulates and fumes. the cheapest solution I could find was $10k.