Shop Fire

Moderatemixed

Moderatemixed

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Hey everyone. I am fairly new to machining and have spent the last 4 years “tooling up” and putting together a shop that I am proud of. It has really only been in the last 6 months that I’ve been starting to really “machine” anything, and most recently have in the last month been actively beginning my “journey” into this hobby. With that said, I started with a drawbar which I am pleased to say that the sixth attempt was “the charm”, lol.

While single point threading the hot chips were curling off the workpiece, the smoke rising from the lubricating oil and it started me thinking. It was later as my shaper was peeling hot chip after hot chip from the piece of metal that I was squaring that again I took notice. I use a dedicated central vac for my shop. It is physically located out in my garage and plumbed into my shop. When chips are vacuumed up they go through the hose, into a stainless steel “dust deputy” cyclonic separator. The heavy chips and debris stay in the separator and air (and I suppose fine material) go through rigid pipe and out to the garage unit.

My concern comes from the reality that in the separator is metal and residual oil. Has anyone ever seen a shop fire occur? How likely is it that the hot chips might start a fire? I generally am not cleaning up until the chips have cooled, but I was vacuuming the ships right off of the shaper and they were really hot, which again was got me thinking about this.

As I have spent a great deal of time setting up shop, watching YouTube tutorial videos and reading virtually everything that I can get my hands on it occurs to me not one bit of information has surfaces on common (outside of common sense) practice regarding fires and machining.

If nothing less perhaps this might get us talking, revisiting time proven practice and sharing ideas and experiences. I fly for an airline and every 6 months we head into the simulator to revisit all “the bad stuff” that can happen so that we’re prepared, or can avoid a bad day. Maybe this thread might have a similar effect, while at the same time as giving those of us who identify as “newbies” the benefit of experience we’d likely all rather avoid.

Best regards all.

Derek.


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Perhaps if you used it as a fume collector, not letting chips into the intake you could relax and not worry about fire there.

It's not a good idea to mix really hot chips and fast moving air. Let the chips cool on the floor and sweep them up.
 
To Benmychree, I presume then that you are sweeping the chips up? How long do you wait? Does the broom have natural or synthetic bristles, as natural bristles might catch fire and synthetic might melt. How long can a chip be of concern? I see lathes in home shops covered with chips, and chip trays full of oily chips, do they simply not present a hazard, or is there a standard practice? If you sweep, what’s a typical wait time? I generally like to leave my shop clean but should I do my clean up the following day? Is there a risk that one of those hot chip in the chip pan might be an issue? Does the cutting oil reduce the risk? Do you put the waste chips into a plastic garbage can or metal? I have a shop fire extinguisher, but has anyone ever needed to use theirs?

Like I said before, I like to think I have common sense, but I am asking because I don’t know. As an example, I put together (years ago when I was into wood working) a dust collection system with plastic pipe. It wasn’t until I asked questions that I grounded the system and ran copper wire through it to avoid sparks; I didn’t know what I didn’t know.

Thanks for the reply’s..... keep them coming.


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I have never seen a fire started that way but you never know. In the winter the first thing I did was run off a big pile of chips as fast as I could and rake them out on the floor to stand on to keep my feet warm.
 
In 34 years of fighting fire i have only seen one vacuum system fire. It was a home central system that the home owner used to clean out a fire place with. Common sense is your best defense in preventing a shop fire. Keep flammable materials cleaned up and away from hot work. Especially oily rags. Not near the danger of working with wood.
 
Make sure you have a couple of fire extinguishers that are fully charged and easy access. If you can’t prevent a problem can you extinguish it!
 
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Interesting question! IMHO, swarf we make in the home shop may be quite hot to start with but don't have the mass to start a fire. A chip may start out essentially red hot but it has a lot of surface area compared to its weight. So it cools within seconds (or less). So when a hot chip lands on your bare skin, it stings but doesn't burn right through.

I'd be more concerned about stringy chips clogging the central vac pipes. In my house, the piping makes some crazy twists and turns going around framing and whatnot. I *think* the rushing air would cool the metal to well below the ignition point of any material in the system but maybe if you got a big clog, there might be enough heat in that mass?

Personally I try to sweep up whenever I finish. Usually. OK, sometimes. Well, once in a while anyway. ;)

Craig
 
Nutfarmer said:
In 34 years of fighting fire i have only seen one vacuum system fire. It was a home central system that the home owner used to clean out a fire place with. Common sense is your best defense in preventing a shop fire. Keep flammable materials cleaned up and away from hot work. Especially oily rags. Not near the danger of working with wood.
Click to expand...

While not exactly the same I have seen a fire started in a vacuum system on a surface grinder at our local technical college. The grinder was not only equipped with a vacuum system it also had a flood coolant system. Due to lack of regular cleaning the dust built up inside the hose. The constant air flow and sparks from grinding dried out enough of the caked on dust that it began to smolder. It only took a couple minutes before about a foot of the hose was smoking. Luckily quick hands with a CO2 extinguisher put it out. Having said that I do use a vacuum on my grinder, but I also clean the hose and vacuum regularly to be sure nothing will start a fire.

As for chips from the shaper, lathes, and mill I have stainless and aluminum guards to direct the chips to designated spots on the floor or chip pan. I let them cool for several minutes then pick up the magnetic ones with a magnetic sweeper like this:

Ironton 18in. Magnetic Floor Sweeper | Northern Tool

The Ironton 18in. Magnetic Floor Sweeper is built with a powerful enclosed magnet box for quick and easy pickup of hardware, scraps, nail...
www.northerntool.com www.northerntool.com

I tried a wider 30" model, but had trouble getting in the tighter places around the machines. For the surface grinder and non-magnetic chips like brass and aluminum from the other machines I use a shop vacuum with a stainless tank similar to this:

 
Steel chips cool so fast I wouldn't worry. I know titanium shavings are easy to combust tho
 
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