SGropp

Oily rags/ fire danger

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There's a lot of discussion on this forum about linseed oil finishes. If you take the time to read the instructions on the can , there is a clear warning about the proper disposal of the oily rags in respect to fire danger. This warning is there for a reason.

A few years ago I was working as a subcontractor on a large estate project. After the tile contractor finished a large slate floor, it was decided to use a ''traditional'' linseed oil and turpentine finish to seal it. After the finish was applied, the rags were carefully laid out to dry in the sun. At the end of the week , someone spread them out loosely on top of a fully loaded construction dumpster.

Monday morning, we all came back to work to find that the rags had caught fire by spontaneous combustion. The steel dumpster was a completely burned and twisted wreck, even the wheels were melted. Two plastic garbage cans that had been next to it were puddles on the driveway. There was a full 500 gallon propane tank about 30' away which was unharmed as well as the clients brand new home about 50' beyond that, also unscathed.

To top it off the linseed oil ''sealer'' was a complete failure, and the whole sticky mess had to be stripped off at great expense.

Whoever did the stripping job did not grasp the lesson of the dumpster fire and piled the rags up in a corner inside the building. As I was leaving that night, I smelled smoke and traced it to the pile of oily rags which were turning brown and starting to smolder . I picked the pile up with a shovel and flung it out the door where it burst into flame.

Two close escapes from disaster is too much for one job.

If you use any kind of oil finish, burn the rags immediately or submerge them in a bucket of water and dispose of them in an airtight plastic bag.

Other rags with paint or solvent residues or lube oils should stored in an approved airtight safety can or burned.

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Shop rags ( read red rags bought from a supplier in bulk ) or shop towels ( read blue towels on a roll ) used for finish seem to accumulate. THe smartest place to stow these for me is IN the coal forge hood ( overnight ). When they lay on a stand beside the anvil and perhaps fall on the floor they will yes catch fire from flying scale. I use a fair amount of olive oil. Over the years I have used some linseed ( raw and boiled ). THe easiest way do fix the linseed rag issue in my shop is to just burn them in the forge ( of course NOT a gasser ). Thanks for the reminder on the rags. It never hurts to be re-educated.

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I recall an investigative report on TV some years ago regarding the safe disposal of linseed oil rags. The conclusion was there is NO safe disposal method other than burning them in a safe place. Even after being washed a few dozen times and placed in an airtight container (cookie tin) they generated enough heat to singe the paint off the can.

Good reminder, thanks for bringing it up.

Frosty

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Any of the vegetable oils (Linseed oil is a vegetable oil made from flax seed) tend to oxidize and produce heat that will cause spontaneous combustion. There has been more than one house fire caused by people wiping up spilled cooking oil with a towel then washing the towel and throwing it in the dryer where it ignited.

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My wife and I had a friend (so-called anyway) over for a few days before we went to a Pow-wow, and he finished about 30 Flutes, and used linseed oil to do the final finish on them, well they left after we did, and when we got home about 4 hours later, we had this really nice looking burn in our spare bedroom floor! It burned through the carpet the padding, and a 1/4" into the subflooring, it burst into flames just as I threw the pile of rags into the yard!! Worse, the jerk told everyone it was just a little scorch mark on the floor, so I took a picture and sent it via e-mail to all the ones who wrote me and told me what he was saying!! He never helped pay for the damage. Some Friend huh?

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WOW!!! Never new that this stuff was that sketchy. I use a combination of boiled linseed, turp, japan, and beeswax and have noticed that it burns rather nice if not a little hard to put out sometimes :D Just yesterday I was finishing a oak shelf by brushing on the paste, running in front of fire then brushing again. It was lets just say interesting. I also have rags everywhere and this is in an old pole barn with lots of lumber and wooden work benches :o Would my mixture (combination of the wax, oil, dryer, turp) still be as dangerous on the rags that are laying everywhere??

Edited by Jeremiah

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Jeremiah, that all depends on if you want to keep the barn, you may want to either clean them up, or stock up on hot dogs.

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One day a few years ago, I serviced our farm tractors in the barn. Just your basic lub and oil change.
Anyway, since it's a messy job, I had scattered oily rags around everywhere during the process.
For the sake of neatness, I piled them up together at the end of the day, planning to dispose of them the next day.
Next morning, when I went back to the barn, I noticed the pile of rags was sort of........SMOKING!
The sun was just coming up and I could see a wisp of smoke from the pile.
When I went to investigate, I touched the pile of rags with my hand and nearly got my hand burned.
I quickly grabbed a rake and got them out of the barn. I scattered 'em out and discovered they wouldn't go out! ( No water was readily available)

I learned to believe in spontaneous combustion that day. If I hadn't went to the barn that morning, the barn might well have burned.

It's one of those things you wouldn't think would happen, but let me assure you...........IT CERTAINLY WILL under the right conditions.

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Some years back I investigated a garage fire. Guess what I found at the point of ignition-you got it-a bucket of linseed oil soaked rags. 'Nuff said.

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I too burn mine in the coal forge. Straight from use to burn.


Does this leave residue in your chimney? Or is it not enough to worry about?

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Not enough to matter much, you'll need to brush it every once in a while anyway. Better to sweep the stack three times a year instead of only two than take a chance of burning the place down.

Burning oily rags in a pair outside if legal would be fine. Just don't leave them laying around.

Frosty

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Old arsonists trick is to leave rags soaked with thinners, turps, linseed etc, tightly rolled up and balled in a place where they won't be noticed and some fuel eg timber scraps, to get it really going. Even better when the weather is hot.
Or so I'm led to believe.
Phil

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Any time you have a fuel/air charge with some heat (especially if the materials generate heat) you will have a fire at some point, if left long enough. This is why there are so many barn fires from hay or straw. Same reason grain silos explode when the elevator malfunctions.

In HS wood shop, several steel drums (30 gal I think) that we dumped sawdust and scrap into had the paint burned off. During a lab period (2 hour) one caught while I was there. We all knew why there was a garden hose in the corner, and why all scrap and sawdust was removed at the end of each class period after that. I do not know if it had oil or oil rags in it too. It was about half full and just smoking a lot when it was doused. It may have been a prank, but nobody acted like it was.

I seal a rag or two in a metal can while I am working on a project, but dispose of it when convenient, no coal forge here.

Phil

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Another way to deal with linseed oil soaked rags is to spread them out in the sun, outside. They dry up and harden. Give them a week or so. Then they are as hard as a board, and can be trashed. Quick and easy to burn them though.

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Ptree, go back and read my original post in regards to the safety of dried out linseed oiled rags in the trash. Not a good idea!

I've had a large commission that's been hanging fire for some time now. I just found out that the client was building another house in New Zealand. The house was finished, everything moved in. That night the place burned to the ground, A multi-million dollar home a total loss. The cause; painters rags left in a heap in a closet.

Another friends sister is the caretaker for a large family estate on the Columbia River. The general contractor that takes care of the estate had subcontracted the job of treating the shake roof on the main lodge with some kind linseed oil based treatment. The subcontractorr left his equipment covered up in a pile outside on a deck. About 10 minutes after the caretaker left ,the pile caught fire and the entire house and several outbuildings burned to the foundation.
Even though the investigation put the cause of the fire to oil soaked rags left by the subcontractor, the insurance company sued the general and he lost everything he owned
and went bankrupt.

Burn those linseed oil soaked rags in the forge or stove ! Better yet ,use a better and safer finish.

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I saw the same thing as the lead in story happen on a job I was working on. Scary! The owner, just by chance, moved the garbage cans from under the eves at the end of the day. next day, we found an ugly plastic mess melted all over the stone path... Better than a nice charred foundation though.... Watch those rags.
personally, I spread them out and or burn them, depending on the job location. That goes for used solvent too.

Thanks for the reminder!

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when I was a kid (20 yrs old ) I worked at an Agway feed mill to supplement my shoeing income, a guy came to show us the danger of working around grain dust. He lit a match, put it in a box with a plexi glass window and blew into a hose to get the dust airborne, the window wasn't necessary because the box blew apart !.....beware of bio dust and oily rags

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I am not arguing the dust, it is worse than a pile of biomass. However a pile of biomass that has adaquate moisture will heat up all on its own and if insulated, will eventually self ignite without a spark.

Airborn dust can be positively scary with how fast and vigerous it ignites contained or not!

BTW moist bulk coal can do this too, but you need several tons in a hopper (read about the Titanic, it had a fire in one of the coal hoppers), don't worry about the 1-2 ton pile in the corner or that skid of bags. Bags is one way to prevent it, as is packing the coal into the pile and keeping it dry till you are ready to use it.

Phil

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Haha, sorry Phil. Wasn't trying to argue. That just happens to be one safety thing that I know, so I figured I'd share. That's also true about the biomass. I've heard tons of stories about compost places catching on fire if they don't rotate the pile around often enough. I didn't think about it.

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One of the many things which I MUST know, but didn’t! I always go to Safety First section. Good thing, I clicked through this one. Added to my safety first list.

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Sorry to re-necro this post, but I noticed no one mentioned using a burn barrel.  If you live in an area where you can have one, you can't beat it as the place to toss those oily rags.  If they catch fire, they are already in a burn barrel! :)

I also use the burn barrel for any personal papers, simplest way I know to stop ID thieves.  Not hard to find an old 55 gal drum.

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