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Shop Fire
- Thread starter Moderatemixed
- Start date
- Joined
- Nov 10, 2013
- Messages
- 837
We used to have vacuum fires pretty often back in the early 90's when our shop first started enforcing a "no smoking inside the workplace" policy. The surface grinder hands would smoke next to the vacuum hoses and let the cigarette go up the chute if a supervisor walked by to keep from getting caught. The lit cigarette would get sucked into the big separator outside and catch the metal dust on fire.
With the exception of aluminum, I vacuum the mess up after I'm done machining.
With the exception of aluminum, I vacuum the mess up after I'm done machining.
- Joined
- Nov 14, 2016
- Messages
- 3,006
The odds of an ignition are quite low. Most of the oils we use are fairly heavy and hard to ignite even with an open flame. Even straight off the cutter the chips are usually not hot enough to ignite these oils and the chips cool rapidly.
However that is exactly how many fire causes are a problem, low risk, high frequency activities combined with complacency. The classic discarded cigarette being a great example. Most discarded cigarettes are just litter, but when 10,000 get flicked out the window on a hot day, a small % of a large number means a few will find the perfect set of circumstances and start a fire.
Same thing with your question, it can be no problem for years, but then that one time when you are using a lighter than normal oil, on a hotter than average day and you are turning a metal that makes an extra hot chip.
Be aware of the risks, minimize them and be prepared when that perfect storm comes together (smoke detectors, fire extinguishers). While the chips and oil combination is rarely an issue, hot chips and other materials most certainly can be, sawdust, trashcan full of paper, flammable liquids, gun powder etc. There have been a few posts here over the years with people sharing their blunders. Most of the fire related ones come back to housekeeping in the shop.
However that is exactly how many fire causes are a problem, low risk, high frequency activities combined with complacency. The classic discarded cigarette being a great example. Most discarded cigarettes are just litter, but when 10,000 get flicked out the window on a hot day, a small % of a large number means a few will find the perfect set of circumstances and start a fire.
Same thing with your question, it can be no problem for years, but then that one time when you are using a lighter than normal oil, on a hotter than average day and you are turning a metal that makes an extra hot chip.
Be aware of the risks, minimize them and be prepared when that perfect storm comes together (smoke detectors, fire extinguishers). While the chips and oil combination is rarely an issue, hot chips and other materials most certainly can be, sawdust, trashcan full of paper, flammable liquids, gun powder etc. There have been a few posts here over the years with people sharing their blunders. Most of the fire related ones come back to housekeeping in the shop.
- Joined
- Feb 7, 2013
- Messages
- 2,487
Have a dry fire extinguisher handy for machining titanium or magnesium. If you weld in the shop, it's best to stay there for a half hour after done welding
to make sure the isn't something smouldering. Sparks from grinders are good at catching sawdust on fire so that's another hazard.
We don't need this:
View media item 94661
to make sure the isn't something smouldering. Sparks from grinders are good at catching sawdust on fire so that's another hazard.
We don't need this:
View media item 94661- Joined
- Mar 17, 2017
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- 19
... keep a bucket of dirt handy too. In the event you have a metal that can ignite, that's a whole other deal. On a side note, the coolest fire I ever ran was an old VW with magnesium in the block. Magnesium burns better in water and flares up when you spray it.
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- Sep 5, 2013
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This isn’t a major safety strategy, just something that I’ve recently put into place within the last year or so. Considering that I’ve had this shop (in my house) for over 30 years it’s a wonder I didn’t think of it sooner.
It has to do with my small shop garbage can. When I was doing mostly woodwork the ideal place for a waste can was right beside my drill press. It fit perfectly there, was out of the way of other things, and when I was drilling holes with a Forstner bit I could just tilt over to one side and all the curls would just drop into the garbage. Perfect!
But now I do mostly metal projects and one day when I was standing there drilling a bunch of holes I thought “hmm, these stringy chips are coming off blue-hot and dropping straight into that little garbage can. There’s floor sweepings, wood chips, sawdust, etc in there. Maybe that’s not such a good idea...”
The obvious thing was to move the can but you know, it really is in the perfect place. On a good day I can shoot the basket with a ball of paper without ever leaving my main work triangle.... . So I did the next best thing — I put a lid on it.
It’s just a scrap piece of 1/8” acrylic I had lying around and I dug up two strap hinges from the hardware drawer. Most of the time I have the seat up, so to speak, so I can still toss stuff in unfettered from anywhere in the room. But, when I’m standing at the drill press and about twenty-five seconds into the first hole, I can reach up with a free foot to flop the lid down. Chips and curls just slide off onto the floor where I can keep an eye on them. Simple but effective, at least for me anyway.
-frank
It has to do with my small shop garbage can. When I was doing mostly woodwork the ideal place for a waste can was right beside my drill press. It fit perfectly there, was out of the way of other things, and when I was drilling holes with a Forstner bit I could just tilt over to one side and all the curls would just drop into the garbage. Perfect!
But now I do mostly metal projects and one day when I was standing there drilling a bunch of holes I thought “hmm, these stringy chips are coming off blue-hot and dropping straight into that little garbage can. There’s floor sweepings, wood chips, sawdust, etc in there. Maybe that’s not such a good idea...”
The obvious thing was to move the can but you know, it really is in the perfect place. On a good day I can shoot the basket with a ball of paper without ever leaving my main work triangle.... . So I did the next best thing — I put a lid on it.
It’s just a scrap piece of 1/8” acrylic I had lying around and I dug up two strap hinges from the hardware drawer. Most of the time I have the seat up, so to speak, so I can still toss stuff in unfettered from anywhere in the room. But, when I’m standing at the drill press and about twenty-five seconds into the first hole, I can reach up with a free foot to flop the lid down. Chips and curls just slide off onto the floor where I can keep an eye on them. Simple but effective, at least for me anyway.
-frank
- Joined
- Feb 1, 2015
- Messages
- 9,621
One thing to consider is the difference between the flash point and auto ignition temperature. The first is the temperature at which a flammable substance will ignite when exposed to an open flame. The second is the temperature at which a substance will spontaneously ignite. The second would be the case when oil was exposed to hot chips.
Lubricating oils have flash points of around 450ºF and auto ignition temperatures of 750 to 1000+ºF. Gasoline has a flash point of -45ºF but an auto ignition temperature of 536ºF.
Additionally, a hot chip coming in contact with oil will quickly be cooled down to a safe temperature. In the process of turning metal using oil as a lubricant, it is common to have hot chips mixed with the vapor from the cutting oil. I have never seen a fire result from this situation.
Lubricating oils have flash points of around 450ºF and auto ignition temperatures of 750 to 1000+ºF. Gasoline has a flash point of -45ºF but an auto ignition temperature of 536ºF.
Additionally, a hot chip coming in contact with oil will quickly be cooled down to a safe temperature. In the process of turning metal using oil as a lubricant, it is common to have hot chips mixed with the vapor from the cutting oil. I have never seen a fire result from this situation.
- Joined
- Nov 25, 2015
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- 335
Having watched and read intently the comments in this thread, I really appreciate everyone’s input. As I said in the beginning, as a novice, I don’t know, what I don’t know. The lid over the garbage can is a great idea. Any other suggestions are welcomed and encouraged. I attribute my successes to the mentorship of the digital and analog Machinist/Metalworking communities alike. My appreciation however comes from knowing that the community is here to ask these seeming mundane or common sense questions and getting quality feedback. I am thoroughly enjoying myself as I get to learn this trade, albeit only as a hobby, and I offer my humble respect and thanks to you all.
Derek.
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Derek.
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- Nov 14, 2016
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Slight correction, flash point is the temperature where enough vapor is produced to cause a flash fire, fire point is just a hair above and the temp where vapor production will sustain a fire. Ignition temp is the temperature needed to ignite the vapors, liquid wont burn. Flashpoint is the major safety difference between diesel fuel and gasoline. Gasoline will produce flammable vapors at subzero temperatures, diesel fuel needs to be around 100 degrees F. So a gasoline fire can occur during a blizzard, but a diesel fire generally needs a hot day (pavement may be much hotter than the ambient air temp, so it doesn't need to be a 100+ day).
Then you get into air fuel mixtures, flammable ranges and all kinds of more technical stuff which is what sets relatively safe propane (flammable range 2-10% in air) from crazy flammable acetylene (2.5-100%).
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- Jul 29, 2014
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- 2,737
I have not had a fire concern (until now!) but I have to get a few more extinguishers and place them strategically.
But a couple days ago I switched cutting oil to LPS something. I was turning some stainless on the lathe, and brushed this stuff on. The work was still hot, and smoke formed instantly. There was an extreme reaction, my eyes began to burn to painful levels, and I brgan coughing nonstop. I had to fumble to get the feed shut off and run outside to breathe.
It made me consider some kind of ventilation fan and maybe a makeshift emergency eyewash station.
This stuff can be serious!
But a couple days ago I switched cutting oil to LPS something. I was turning some stainless on the lathe, and brushed this stuff on. The work was still hot, and smoke formed instantly. There was an extreme reaction, my eyes began to burn to painful levels, and I brgan coughing nonstop. I had to fumble to get the feed shut off and run outside to breathe.
It made me consider some kind of ventilation fan and maybe a makeshift emergency eyewash station.
This stuff can be serious!