Used oil rags

Hengelo_77

Hengelo_77

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Most wood working books and (wood)oil containers warn that the rags used to apply and rub out the oil can smuther and ignite.
My question is when is the danger over?
Can the rags be thrown away or re-used once the oil has dried or do I have to keep them wet and save?
 
out of interest when were those books published.?
I seem to remember reading that Tung oil and whale oil soaked rags would spontaneously ignite.
I think it meant large piles of rags which act like a compost heap.Say in an industrial setting.
The stuff is not extremely volatile but is flammable such as linseed oil.
I have used it on axe handles and thrown the rag in the bin in my garage(under the house) with no problem.
I would recommend throwing away the used rag and using clean ones.

Hey once its at the tip who cares if bursts into flame?
 
The old stories of spontaneous combustion in hay ricks and oil rag piles comes from a day when furniture shops used tack rags to remove sanding dust before varnishing, and again when rubbing in the finish. These oil and varnish soaked rags were tossed in a pile in the corner. Due to polymerization of the resins, the pile would get warm. When there would be a fire in the shop at night, the pile of rags was blamed for "spontaneously" igniting due to the heat. What was the truth was that in those days everyone smoked everywhere. They smoked while pumping gas, working with naphtha, laying in a hay stack,...... No one wanted to say it was the cigarettes that caused the fires. With the advent of Fire Codes, they put metal pails in shops to put the rags in and the problem was solved..........Now, wouldn't those rags catch fire in a pile in the pails just as easy, Hmmmmmm.
Since the end of smoking in most factory situations in the US and developed countries, the number of factory and woodshop fires has gone to near zero. In other parts of the world, where smoking is still the norm at work, fabric and wood industry factories and shops still burn down regularly.

When hay is fresh cut, it has to be stacked in ricks to dry.You can't put up fresh hay, or it will sour in the loft and be no good for the animals. The drying haystacks can start to ferment in the center,especially if it gets wet with rain. This makes it "smoke" with water vapor and methane as it gets hot ,due to the fermentation. While pretty hot to the touch in the center of these giant compost piles, the chances of it reaching 500-700F ( ignition temp) is unlikely. However, the chance of lightning or a careless spark from many possible sources, including a cigarette carelessly tossed away, was high. Again, the hay was said to have spontaneously combusted. The same goes for when a barn would burn down in the middle of the night. The hay was said to have "spontaneously combusted". The fact that a hobo or farm worker crushed out his cigarette on the hay strewn floor, or fell asleep in the hay smoking, was not considered.

Good shop practise dictates putting flamable things away and hanging rags soaked in volatile things out to dry......and not smoking in the shop.
Sparks from our grinding is the number one source of ignition in the blade shop, and in some cases the barn......Just ask Raymond Richards.
 
We had teak furniture for the past 10 years. We used teak oil on this in the spring and I had the experience of hot rags that were in a pile. Father that we always put the in a sealed bag outside. A bit scary to find a hot pile of rags.
 
Stacy is one of the only people I've ever heard address this what I believe to be correctly. I painted
for a day job for 25 years everything from flat oil at the beginning of latex to 35-50 gal. of Sikkens
(interestingly enough made by dynamit nobel the dynamite company) on log homes. While I won't say
its never happened. I strongly believe its more of a yuppie or more accuratley sheeple way of passing the
buck. Would I leave a pile of stain rags in a pile on a job? NO.
Ken.
 
Wet hay fires still happen here once in a while, although wrapped bales stored outside are more common now and less likely to burn.


According to this the temperature required is far less than the 450 F ish that it takes for paper to burn.
apparently it's the accumulation of volatile gasses that burn so the temps are lower.

http://ext.wsu.edu/hay-combustion.html


For the most part though, good hygiene and the elimination of smoking has done a lot.
It astounds and ticks me off how careless people are with fire.
It's entirely possible for birds to bring a discarded lit butt back to the nest, which is a perfect tinder bundle.


I think the safety codes that specify can rags also include a lid, usually a self closing lid.
I assume the lack of oxygen is what reduces that risk.


I tend to use a rag once, so no accumulation of several rags.
After using linseed oil rags I've always either burned it right away or tossed into a firepit (safe if it did burn) or, rinsed in water and hung to dry outside, or put into a sealed can.

Heat, Fuel, Oxygen try and remove 1 or 2 of those and you won't have fire.


I almost burned the shop down with sparks on an oily rag too.
It was smouldering and I couldn't smell it with the respirator on.

I think it's good practice to have 1/2 hour clean-up / down time after working to prevent or detect this sort of thing.
 
My experience:
I had soaked an old tomahawk handle in a bucket of linseed oil out back for a few days, rotaing it top to bottom every day to get a good soak. Wiped off the excess with paper towels and threw them in my metal shop trash can with other trash. Debated going to see a movie with the wife but we decided to stay in that evening. Couple hours later i heard a light metallic clanking in the garage, figured i left the garage door open and someone was snooping around. When i opened the door to the garage the flames were to the ceiling!!!!!!!!! As i cussed my way to the fire extinguisher i realized the rags had combusted and the metal clanking sound was my air compressor expanding :0 as it was next to the blaze. I put it out, rolled the wifes car out of the smoke, and began clean up....took weeks for the smell to go away, but luckily i only lost a garbage can. If we had gone to the movies we might have lost our whole house. P.s. i dont smoke, and didnt do any grinding that day.

Advice i was given by others is to rinse with water then lay out any rag or towel to airdry before putting in the trash.
 
You say what you want but I had a linseed rag billowing smoke in the center of my workbench about 4 yrs ago. I had just made a new leather working table and wiped the top down with boiled linseed. I threw the rag(old cotton t-shirt) on the bench after it was done. 2-3hrs later I smelled smoke and sure enough, the rag was literally pumping out a thick cloud. The center was completely charred. I can't be 100% certain it would have gone to flame, the char was dark brown, not black. It may have just smoked itself out... but it was sure an eye opener. I lay them out flat between use and changed my rubbermaid garbage in for a steel bin with a lid.

The threat is valid. At least when it comes to boiled linseed oil.
 
Oxidation creates heat .In a metal container if the rags ignite the oxygen in the can is quickly consumed ,ending the fire . Spontaneous combustion also is a problem with coal .The battleship Maine was not as originally assumed , an enemy torpedo casualty. I was spontaneous combustion of the coal ,not uncommon , and poor design. The coal bunker was next to the powder magazine !!! As the coal burned the black powder got hot and exploded ! All those ships with that design were at risk especially in the tropics.
 
You say what you want but I had a linseed rag billowing smoke in the center of my workbench about 4 yrs ago. I had just made a new leather working table and wiped the top down with boiled linseed. I threw the rag(old cotton t-shirt) on the bench after it was done. 2-3hrs later I smelled smoke and sure enough, the rag was literally pumping out a thick cloud. The center was completely charred. I can't be 100% certain it would have gone to flame, the char was dark brown, not black. It amy have just smoked out... but it was sure an eye opener. I lay them out flat between use and changed my rubbermaid garbage in for a steel bin with a lid.
Click to expand...

Back when I was doing construction for a living, some of my coworkers were tasked with building a play house inside a local shopping mall for a charity give-away event. They had the exact same experience you did. The oil used was boiled linseed oil and the rag was one of those red cotton shop rags that they sell by the bag in some hardware stores.

I wasn't there to see it, I was working at a different site when it happened, but I have absolutely no reason to doubt these guys. I've known them the better part of my life, and they wouldn't make up something like this. They said the rag started smoking, and when they saw it, it was charred up pretty bad. They took it outside and extinguished it before it actually caught fire, so I don't know whether it would have actually caught flame. It was just sort of smoldering when they extinguished it.

I had heard tale of it happening, but I didn't know if it was just an old wives' tale. After that, I don't leave oily rags around.


Jason
 
When I was a smoker I was always annoyed when people attributed any and all inexplicable fires to careless smokers. I don't deny that careless smokers exist, and that they account for some fires... but the assertion that any fire not attributable to some other combustion source were started by careless smokers always annoyed me.

I quit smoking over 18 years ago, and no longer have sensitivity on the subject. However, intellectually I am still not convinced that there is any evidence to suggest inexplicable fires are caused by smokers. That really is little more than anti-smoker prejudice. And while as an ex-smoker I now have a healthy dose of anti-smoker prejudice, I also have a strong sense of fairness, and don't see any reason to lay this at their doorstep.

That said, I have a hard time accepting many of the spontaneous combustion arguments too, without some better explanation of how they occur. As a case in point, the explanation of hay fires based on the gases produced during fermentation is more satisfying to me than the one about crows dropping lit cigarettes.

So could someone please offer an explanation of why oily rags in the absence of a spark or flame generate enough energy by themselves to spontaneously combust? If not, then I have so suggest we're missing some information (and missing information does NOT translate into magically materializing cigarette butts).

- Greg
 
So could someone please offer an explanation of why oily rags in the absence of a spark or flame generate enough energy by themselves to spontaneously combust? If not, then I have so suggest we're missing some information (and missing information does NOT translate into magically materializing cigarette butts).

- Greg
Click to expand...

Linseed oil is an organic triglyceride that contains linoleic acid in its fatty acid subunits, that will oxidize when exposed to air. It's an exothermic reaction, meaning heat is released into the surrounding environment. If the surrounding environment is thermally insulative, such as in a wadded up rag, the heat is trapped and builds up as the reaction continues. The rate of the reaction would probably also be sped up by the large surface area of the rag, meaning faster accumulation of heat. Get enough heat going, and the oily rag will approach flashpoint (probably the flashpoint of the oil would be reached before the self ignition point of the cotton).



Jason
 
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tryppyr said:
When I was a smoker I was always annoyed when people attributed any and all inexplicable fires to careless smokers. I don't deny that careless smokers exist, and that they account for some fires... but the assertion that any fire not attributable to some other combustion source were started by careless smokers always annoyed me.

I quit smoking over 18 years ago, and no longer have sensitivity on the subject. However, intellectually I am still not convinced that there is any evidence to suggest inexplicable fires are caused by smokers. That really is little more than anti-smoker prejudice. And while as an ex-smoker I now have a healthy dose of anti-smoker prejudice, I also have a strong sense of fairness, and don't see any reason to lay this at their doorstep.

That said, I have a hard time accepting many of the spontaneous combustion arguments too, without some better explanation of how they occur. As a case in point, the explanation of hay fires based on the gases produced during fermentation is more satisfying to me than the one about crows dropping lit cigarettes.

So could someone please offer an explanation of why oily rags in the absence of a spark or flame generate enough energy by themselves to spontaneously combust? If not, then I have so suggest we're missing some information (and missing information does NOT translate into magically materializing cigarette butts).

- Greg
Click to expand...

If we are missing info, the so be it but the result is still the same. this could be ambient temperature, humidity, rag material, type of oil. Now if you question that this can happen, buy some oil from he or lowes and try this experiment. Please have a fire extinguisher on hand though and please have a camera for the photos. And please take a photo of your astonished face. :)
 
Thanks, Jason and Rick. That makes sense.

PT, all too often we blame "careless kids" or other groups (e.g. smokers) that we don't particularly like for things that we do because we lack information. Being armed with information is, to my way of thinking, infinitely more helpful than being armed with ready targets of blame.
 
Yeah, but those targets are soooo easy! Anything easy has got to be right.... right:confused::o:p
 
Thnx for all the input, guys.
So rags should best be hung out dry (oxidice) And once they are dry they are safe to be thrown away?
(I've lost an appartement to a fire once. I'm extra cautious when it comes to fire)
 
So rags should best be hung out dry (oxidice) And once they are dry they are safe to be thrown away?
(I've lost an appartement to a fire once. I'm extra cautious when it comes to fire)
Click to expand...

To be honest, I don't know what the best way of dealing with a linseed oil-soaked rag is, but I usually douse them really good with a water hose and some detergent, and then set them somewhere that they wouldn't catch anything else on fire if they did combust. I've never had one smolder.


Jason
 
They are fine once the oil has dried. A deep bin or preferably one with a lid will ensure there are no flare-ups. It's like puting a lid on a burning deepfrier... no oxygen, no fire. Remember, it needs time to cook and the process requires oxygen... let it starve. I don't lose sleep over it, anymore.
 
I probably should have prefaced my post with the statement that spontaneous combustion is real. What I was trying to point out was that it is often blamed for things that have other causes.

I agree that certain chemicals, like boiled linseed oil, will oxidize at room temperature and can get hot enough to ignite low combustion fuels like cotton.

I always rinse out oil rags and store in a zip-lock bag. It is good shop practice in general.
 
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