I'm not very knowledgeable on the subject but I had intended to use a cyclone separator and maybe put an inch of water in the bottom when working metal. I do woodworking as well so it's something I need regardless. Since it uses a bucket to collect debris it's easy to clean out the sawdust before working on metal.
Michael
Fail. You cannot suck hot sparks into any container w/ saw dust. That unit is a centrufugal seperator of sorts & will just seperate out some of the heavier sparks but not all of them. Plus, if you have a nice layer of saw dust floating on top of the water in the bottom of the bucket your sparks will light them on fire. Even if you only use it for metal, some of the sparks will go into your vacuum. Unless you are just blowing stuff through a blower out a duckt w/o a filter you still can't use that thing. You need a dedicated system for sparks that just blows them outside into a bucket of water or you need to make a bong like we said so the hot sparks get sucked under water & cooled & trapped in the water.
I'll also use the bong to filter out tear gas in case THEY come for me!!!
Crap, no tin foil beanie emoticon.