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Thread: Spontaneous Combustion - A must see video

  1. #31
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    I would think so unless the oil and water emulsify, which I'm guessing is what happens over a few days? When I put rags in water for a few days, the water is definitely oily so seems to be what is called emulsion.

    So maybe at that point there isn't enough oil to oxidize and/or the oil has already been oxidized (which is the exothermic reaction that can cause combustion in a pile of rags. There is oxygen in water.). Or not enough oil to worry about the temp increasing. It sounds like the big problem is enough surface area to oxidize while also a pile tight enough that the heat can't escape -> more heat = faster reaction -> continue this trend until you reach the combustion temperature of the oil. Furthermore, it sounds like Linseed Oil oxidizes really quickly and has a low combustion temp which is why it is especially likely to combust while other oils are less so.

    https://www.heads-up.biz/linseed-oil

  2. #32
    Quote Originally Posted by Phillip Mitchell View Post
    ? What do you do with old / used solvent, paint, etc? Does your local landfill not have designated days and areas that they collect such things to prevent people from just mixing them in the normal household trash, or worse, just pouring them out outside or in septic/sewer systems?

    This is what is legally required in my state and area and what I was taught from a couple different commercial shops in this area. Oily water leftover from soaking finished rags is very similar to old solvent/paint/other finishing supplies. Not sure what is gross about that compared to any other finishing supplies that need to be disposed of accordingly.


    Yes, in my area there is a hazardous waste collection site, where I take paint, etc. if necessary- not the landfill as you stated.

    I try to minimize waste generally and toxics in particular, so avoid generating a bunch of oily waste water.

    I haven't had a problem with spreading rags out to dry, but James Pallas' story is cautionary for sure.

  3. #33
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    Thanks for sharing this Jim. I'll be buying a finish fire cabinet as well as a fire garbage can after watching this. I always assumed that a rag laid flat on my concrete floor would be safe enough, but if 3 samples caught fire here, I'm not going to play those odds

  4. #34
    Quote Originally Posted by andrew whicker View Post
    I would think so unless the oil and water emulsify, which I'm guessing is what happens over a few days? When I put rags in water for a few days, the water is definitely oily so seems to be what is called emulsion.

    So maybe at that point there isn't enough oil to oxidize and/or the oil has already been oxidized (which is the exothermic reaction that can cause combustion in a pile of rags. There is oxygen in water.). Or not enough oil to worry about the temp increasing. It sounds like the big problem is enough surface area to oxidize while also a pile tight enough that the heat can't escape -> more heat = faster reaction -> continue this trend until you reach the combustion temperature of the oil. Furthermore, it sounds like Linseed Oil oxidizes really quickly and has a low combustion temp which is why it is especially likely to combust while other oils are less so.

    https://www.heads-up.biz/linseed-oil

    An observation from industry: an emulsion is generally an oil/water mix and then highly agitated (think margarine), oil 'floating' on water is not an emulsion. ...minor point, semantics, moving on.

    I don't know the exact 'chemistry' of the oily rag + water, but suspect that oxygen introduced from spreading (aeration), the air in the weave of the rag, and the water is enough to begin, and sustain curing. Even in water.

    My understanding of the hazard mitigation provided by water-soaked finish rags is that it is almost 100% heat transfer related. The heat generated in a balled-up finish rag can't escape (convection) while buried in a trash can, so internal temperatures climb. But sitting in water and a metal can, that heat is easily carried away - ultimately to atmosphere - well before ignition temperatures are reached.

    I lay mine flat to dry on concrete (inside :: no wind to wad them up, blow them to a wood fence, and burn the world). Off-gassing? Smell? Hmm, hmm good. I love the smell of tung oil in the morning. It smells like ... another project ready to deliver.

  5. #35
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    A cautionary tale for sure - thx for posting Jim. When I'm finishing a project, I collect the rags as I go in a metal bucket, and when I'm done, I dump the bucket in the fire pit out back. Never once have they combusted, but it sure is possible. I've always had to go out at the end of the day with the cut offs, light the rags, and a cigar, and sit and relax by the fire. Very decompressing after a day in the shop.
    Stand for something, or you'll fall for anything.

  6. #36
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    Awesome thanks. What is oil floating in water called?

  7. #37
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    Quote Originally Posted by andrew whicker View Post
    Awesome thanks. What is oil floating in water called?
    A mess waiting to happen?
    --

    The most expensive tool is the one you buy "cheaply" and often...

  8. #38
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    I donít know anything about the chemistry. I do know that what I call the old timers, experienced workers from the 1960ís were very aware if this issue. I was well schooled on the subject. I didnít know why but followed their lead. NO OILY RAGS LEFT LAYING IN A BUILDING, even for a few minutes like lunch time. When the pallet incident occurred I knew why. Soak well in water, for some hours wring out a couple of times, outside to dry and then to the trash.

  9. #39
    Oil floating in water is called ďpond scumĒ.

  10. #40
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    I also like this guy. I appreciate the time he put into the experiment. It's a great reminder. I manage a machine shop where millwrights share the common space. Lots of rags are used, and we have always segregated oil soaked rags from other 'trash' for this very reason. They have always been placed in metal cans with clear bags, and they have always been required to be covered with a lid. It must have been about 7 or 8 years ago that one of the state's safety and fed OSHA inspectors (annual facility inspections) recommended that we replace the metal trash cans with purpose build fire cans..... I've always known there is a potential for rags to light off, but I admit that I have not actually seen it demonstrated in the manor that Jason has done with this video. I'll be sharing the link with my team.

    Not real sure why some feel the need to judge, but I suspect it's just human nature. Much easier to critique the work of others, than actually contribute or help. Could he have done this better, safer, - sure. Seems to me that did put some thought and effort into this, and I appreciate his efforts.
    Last edited by Michael Drew; 03-26-2023 at 12:40 PM.

  11. #41
    Quote Originally Posted by Michael Drew View Post
    Not real sure why some feel the need to judge, but I suspect it's just human nature. Much easier to critique the work of others, than actually contribute or help. Could he have done this better, safer, - sure. Seems to me that did put some thought and effort into this, and I appreciate his efforts.
    Cunningham's law

    Also, not to pile on but there were some things in the video that weren't totally thought out, IMO

    Be safe

  12. #42
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    Quote Originally Posted by Edward Weber View Post
    Cunningham's law

    Also, not to pile on but there were some things in the video that weren't totally thought out, IMO

    Be safe
    I'm pretty sure he did not think he would get the results he did. I know better, and still found myself surprised things went they way they did.

  13. #43
    Personally, I just would have liked to have seen a little more fire safety, considering the subject matter.
    Having the extinguisher closer, knowing how to use it and having a more direct, clear path to the safety of outdoors.

    He is after all, a Youtube content creator, that's his job. If he gets criticism, that's part of the gig. It doesn't matter what the subject is.

    I've commented on videos where I think others need to know what they're watching is potential dangerous only to be told to basically shut up.
    You really can't win.

  14. #44
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    I hang mine on a gate, a chain-link gate, until they have dried completely. Then into the trash.
    Ken

  15. #45
    Been around a while and know lots of people custom car builders cabinetmakers and never seen anyone put wet rags in a bag and leave it in their shop in the last 50 years and not sure why anyone would.

    Never seen anyone put wet rags into a plastic garbage can nor rags with sawdust or other.

    Flat on the floor was supposed to be okay and did it the odd time, never saw heat with the heat gauge. If reusing hung stuff up never saw heat from them and reused them several times if they didn't harden up too much. They usually softened up right away if reused.

    Always saw the special metal cans that were air tight and had some special air circulation that helped cool any heat produced. Never saw water used in them.

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