Recipe for disaster.

[Bill Wyko]

The other night I was applying Boiled linseed oil to a piece of wood. I set the rag down meaning to dispose of it shortly. I went on to filling my spray gun with lacquer. I dropped the can of lacquer with a full quart in it. Needless to say, I forgot all about the rag I was using for the linseed oil. Now I have set up the scenario for a disaster. Linseed oil will spontaneously ignite. I now have a shop full of fumes from the lacquer and a rag that is going to ignite. Fortunately I had opened all the windows and turned on fans and left the shop open all night this way. Had I closed up the shop I believe the rag would have ignited the fumes and blown my shop up like 10 sticks of dynamite. I know many of you are hobbyists. Please be aware that many finishes will self ignite when saturated in a rag. I almost lost everything this weekend due to a stupid rag. I wanted to share this with you guys just to make you aware of what can happen when you get distracted. Other than that, have fun with your hobby. http://www.cigarpass.com/forums/public/style_emoticons/default/biggrin.gif
http://pic80.picturetrail.com/VOL2109/11908737/21546032/377656697.jpg

[Jeffrey Makiel]

Bill,
Your post is a good reminder. I'm glad it was a near miss for you.
-Jeff :)

[Doug Shepard]

I had something similar almost happen with excess epoxy that I left in a small plastic container. Went back about 15 minutes later to find the container smoking and hot enough I couldn't pick it up. I think another 5 minutes and it would have burst into flames.

[Michael Schapansky]

2 months ago I was cleaning up a truck that had been in storage for 3 years. I was using a spray bottle of 409 and paper towels. The used paper towels were tossed into a 5 gallon plastic pail. When I was done I straightened up and put the pail up against the garage door. I was putting tools away in the shop when I smelled smoke. Went outside and found my plastic pail was getting hot. I moved the pail to the middle of the driveway and sure enough, within 10 minutes there were flames. I have heard of oily rags catching fire all my life and I've been careful about them. This is the first time I'd heard of cleaning fluid catching fire. It's possible I had cleaned up some oil, but if so it would have been a minuscule amount since I was working on the interior of the truck. Sure glad I was in a position to smell that smoke. The garage door that the pail was up against is wood.

[glenn bradley]

Yet another good reminder. I sometimes think about not taking the time to put a couple inches of water in the bucket I use for BLO cast-offs during a finishing session. Then I think of posts like yours and am thankful for them as I turn on the water.

[Mike Cruz]

Not reag and fluid related, but about 6 months ago, while in my shop, I could swear I smelled something burning! I looked around...nothing. I went outside, the smell was gone. Went back inside, there was the smell again. I did this about 3 or4 times. Finally, I looked up (I have 10' ceilings to my rafters). I have flourescent lights. I forget what the things are called, one of the contacts that the ends of the long light bulbs "push" into was smoking!

I quickly turned off the lights and let it set and cool. When I the bulb out, I noticed that end terminal of the light fixture was melted away (amazing it still conducted power to the bulb). I have left my shop PLENTY of times with the lights on while running out to do other things on the farm. LUCKILY, I was in there when it happened. I, too, could have lost everything in my shop...shop included.

I have 11 of these 6' double bulb lights in my shop. I paniced and wanted to know just what caused this. Talking to the the electriacal guy at HD (where I bought the lights), a specialty electrical store, and my local electrician, the best explanation is that SOMETHING got in there and short circuited it...likely a stink bug. Blasted little creatures!

As if its not bad enough that China is infiltrating our economy, it has to infiltrate us biologically, too. Don't know about ya'll's neck of the woods, but they are EVERYWHERE here (stink bugs...not Chineese :rolleyes:). Move something that has been sitting for a month and you are likely to find 100 of 'em all cozy and snuggled together.

NOTE: That was not a slight at Chinese folks, just a clarification. ;)

[Walt Nicholson]

One of our local detention facilities used a lot of cloth rags with Windex to clean all their windows then put them in the washer and dryer. The operator opened the dryer at the end of the cycle (high heat) and the whole inside burst into flames. The fire department said the residual Windex left in the rags, heat in the dryer, and sudden exposure to more oxygen caused the ignition. Never would have thought it.

[Conrad Fiore]

Did I hear someone say "MYTHBUSTERS"?

[Brian Walter]

I know you are supposed to place your oily rags in a bucket of water to prevent spontaneous combustion, but what do you do with the bucket of wet oily rags? I typically spread out my oily rags, laying them flat on the concrete until they dry out and then throw them in the trash outside. I would probably use the water bucket method if I knew what to do with the bucket of rags. Any help would be appreciated.

Brian Walter

[glenn bradley]

I know you are supposed to place your oily rags in a bucket of water to prevent spontaneous combustion, but what do you do with the bucket of wet oily rags? I typically spread out my oily rags, laying them flat on the concrete until they dry out and then throw them in the trash outside. I would probably use the water bucket method if I knew what to do with the bucket of rags. Any help would be appreciated.

Brian Walter

That's easy. I use the bucket so I can quickly discard rags while in the process without the danger of "forgetting" one on the floor or stopping to go outside when changing to a fresh rag. Once I am done with the BLO session I take the bucket outside, spread the rags to dry (with rocks on them, we have wind) and then toss them in the trash.

[Sherzod Niazov]

So a rag soaked in BLO should be soaked in water... but what about the project it was just used on...?!

Not trying to argue, I always dry rags on concrete, but it just crossed my mind.

[george wilson]

I use the type of oily rag containers that have lids that you step on a pedal to raise. Now I've forgotten the name,though I know it perfectly well. Never bought one. I kept getting them out of a dumpster. They aren't real cheap.

In the cabinet shop in Colonial Williamsburg,their trash can full of shavings started smoking once when some newbie put oily rags into it. That place is like a tinderbox!!

[Walt Nicholson]

Did a little research on my earlier post about Windex and fire and found the following about the chemical composition of Windex; "The Sam Wise patent #3,463,735 lists several example formulae, one of which is 4.0% isopropyl alcohol (http://en.wikipedia.org/wiki/Isopropyl_alcohol) (a highly volatile solvent) 1% ethylene glycol monobutyl ether (http://en.wikipedia.org/wiki/2-Butoxyethanol) (a less volatile solvent), 0.1% sodium laurel sulfate (http://en.wikipedia.org/wiki/Sodium_laurel_sulfate) (a surfactant), 0.01% tetrasodium pyrophosphate (http://en.wikipedia.org/wiki/Tetrasodium_pyrophosphate) (a water softener), 0.05% of 28% ammonia (http://en.wikipedia.org/wiki/Ammonia), 1% of a dye solution, and 0.01% perfume." So in theory, if the volatile solvents remained in the rags after the washing (water does not dilute them) and they were subjected to the heat in a commercial dryer, combustion is very possible. The scariest part about this is the combination of bleach (lots of folks use that to clean rags) and the ammonia in Windex creates chlorine gas which is deadly. There are warnings all over the net about mixing the two. Maybe I need to build a hazardous waste site in the back yard for all my cleaning materials, brushes and rags. That way I could wear the haz-mat suit all the time in the shop and not have to spend all that money on a dust collecter!:D

[William M Johnson]

Walt, if we are going to talk science, all of the solvents listed (alcohol, ethylene glycol and ammonia) are "Polar" solvents are do indeed get diluted by water. You confusing them with "Non Polar" (hydrocarbon) solvents, like boiled linseed oil that are not water soluable.

You could not get 4% isopropyl alcohol to burn with a torch.;)

[glenn bradley]

So a rag soaked in BLO should be soaked in water... but what about the project it was just used on...?!

Not trying to argue, I always dry rags on concrete, but it just crossed my mind.

Hmm, I'm not saying they "should" be soaked in water. I am saying that when I BLO a large project, I will go through a series of rags. As a used rag is discarded, I want a place I can just toss it so I can grab another and not lose momentum. A bucket with water just gives me a safe place to toss the used rags without the danger of 'fogetting' to pick one up or tossing it somewhere that I will miss when cleaning up.

It could just be the way I work but when I am finishing, if I tossed rags on the floor they could set there for quite awhile till I take a break. Then, addled by the fumes and old age I might wander off for a cup of coffee. Then someone will call on the phone and then I'll remember to go out and get the mail. Sooner or later I might just go to bed and then I get woke up by the fire engines pulling up out front :rolleyes:.

Seriously though; its just a precaution like a splitter or a pushblock or keeping a clear walkway. If I could trust myself to never, ever do as Bill did, I wouldn't worry about it. I'm just protecting me from myself.

P.s. let me say I am jealous of George as I would love to have one of those 'step on to open' rag cans and skip the water but, they are too pricey for me. I better check some dumpsters ;-)

[gary Zimmel]

Good to hear something really bad didn't happen Bill.

And thanks for the reminder that things can go bad real quickly..

[harry strasil]

they stopped making danish oil for awhile because of spontaneous combustion in some guys shop.

One time our fire dept was called to a residence because of a strong smell like some sort of smoke. I was our chief at the time, and even tho I have smoked since boot camp and have been a weldor all my life, I have a very sensitive smeller, I sort of traced the smell by its intensity to the basement where a bunch of wet towels were laying on the floor. They were bar towels and she put them on a clean piece of cloth on the floor as the dryer was still running. I moved a couple of the top towels and there was the evidence and a really strong odor and some places on the wet bar towels were singed black. They got taken outside and dumped on the lawn real quick.

[joe milana]

Can someone explain the science of "spontaneous combustion" of oily rags? Why don't the recently oiled woodworking pieces go up in flames, or the spilled linseed oil on the top of the can (or on the floor) combined with sawdust go up either? Anyone wiped an oily finger on the side of their jeans and gone up in flames? I'm not trying to be a smart ass, and I do throw my oily rags in a metal bucket, but do you guys that experience "spontaneous combustion" smoke? Do metalwork in your woodshop? Route dado's in Chinese plywood near oily rags? Seems there must be an explanation...

[Jim Mackell]

Harry, we had a similar call some years back. Local family was refinishing wood using a work room in their 100 year old barn. Lots of BLO and some lacquer. Boards were leaned against every available wall surface to dry. After they went to bed, the rags ignited spontaneously, newly applied finish on the boards ignited and then the fire just died.:eek: Just didn't have quite enough BTU's to actually ignite the wood itself.

Lots of smoke. Told the homeowner that whatever church he was attending was the right one for him.

[harry strasil]

How spontaneous combustion occurs
A substance with a relatively low ignition temperature begins to release heat, which may occur in several ways, such as oxidation or fermentation.
The heat is unable to escape, and the temperature of the material rises
The temperature of the material rises above its ignition point
Combustion begins if a sufficiently strong oxidizer, such as oxygen, is present.


Linseed oil in a partially confined space (such as a pile of oil-soaked rags left out in an uncovered container) can oxidize leading to a buildup of heat and thus ignition.

[Dave Lehnert]

I never put my rags down. When done I toss them out the door into the yard. I let them sit a day or two before placing in the trash.

[Walt Nicholson]

William, you got me there. I know less about chemistry than I do about what makes my wife tick. I just copied and pasted the whole thing from Wikkipedia that came up when I googled Windex. Go figure. :D

[george wilson]

I suppose the towels offer more surface area to the oil in them,and more of a chance to oxidize quickly.

I am also one who tosses oily paper towels out the shop door into the yard until they get good and dry.

I must have gotten at least 4 oily waste cans out of the Williamsburg dumpster. The threw out some pretty nice stuff! I think they'd send in a cleaning crew to clear out a space to use for something else,and they'd just toss most stuff in the dumpster. We used to call it "The employee Benefits Package.!"

My buddy found some genuine Hogarth prints in there once.

On another occasion,they threw away the cast iron cannon carriage wheels from the 2 cannon outside the Governor's Palace. My shop was going to have to make patterns for casting new ones,and machine the finished castings. This was going to cost $6,000.00.

Just before we were having a meeting with the Geddy foundry to discuss the project,a maintenance guy said that he'd been keeping them in his pickup truck's bed for better traction. He sold them back to them for only $2.000.00!!!

The wheels had been demounted while new wooden carriages were being made. They were tossed by mistake. I was glad to get out of that job. Those wheels were VERY heavy,and cast iron is filthy to machine. Ever since we made the fire engine,I was the official pattern maker for whatever came along,like cast iron cookware,lathe parts for treadle lathes,or whatever.

[Michael O'Sullivan]

Can someone explain the science of "spontaneous combustion" of oily rags? Why don't the recently oiled woodworking pieces go up in flames, or the spilled linseed oil on the top of the can (or on the floor) combined with sawdust go up either? Anyone wiped an oily finger on the side of their jeans and gone up in flames? I'm not trying to be a smart ass, and I do throw my oily rags in a metal bucket, but do you guys that experience "spontaneous combustion" smoke? Do metalwork in your woodshop? Route dado's in Chinese plywood near oily rags? Seems there must be an explanation...Oils (and various other chemicals) do not dry by evaporation the way shellac or lacquer does. Instead, they "cure," a chemical reaction that releases heat as a byproduct. Normally, that is not an issue -- for example, when BLO is applied to a piece of wood, the heat created by the curing process is generated slowly, and dissipates into the air without even being noticeable.

However, when oily rags are piled on top of one another, two additional factors come into play. First, there is nowhere for the heat to dissipate, so it builds up inside the pile. Second, the rags themselves are more susceptible to smoldering as the heat increases than oil all by itself. Once the rags begin to smolder, though, the oil can act as an accelerant. Bad stuff can then ensue.

DAMHIKT, but if you have ever accidentally stick your fingers together with super glue, you will feel a searing burst of heat. That is the glue curing, and if you fail to yank your fingers apart immediately, a trip to the ER may be in order.

Another real-world example of the amount of heat generated by "curing" is poured concrete. It needs to be poured in batches because of the amount of heat released as it cures -- if you were to pour too much at once, it would crack.

[Dean Karavite]

Bill, I'm very glad you caught this and avoided much worse. Some people poo poo the risk here, but I take the overly cautionary approach - right in a bucket of water and then the bucket goes outside. I know it's overkill, but piece of mind is what I'm after. Stay safe.

[Jeff Dege]

1: A reaction occurs that generates heat.
2: The heat is unable to escape, and the temperature rises.
3: The higher temperature increases the rate at which the reaction occurs.
4: The faster reaction raises the temperature further.
5: If oxygen is present and temperature > ignition point, go to 7
6: go to 3
7: burst into flames

Note that if oxygen is not present, very high temperatures can be achieved without catching fire. In this case, disturbing the rags and allowing air in can result in a very large and very nasty fire, pretty much instantaneously.

[Matt Sollars]

Is there a list of popular finishes or 'Shop Chemicals' that talks about disposal. I'm cleaning with mineral spirits and thinner and you've all got me worried about how to dispose of my rags.

As a beginner to all of this stuff....a list like this would be awesome.

Thanks.

Matt

[Bill Wyko]

Can someone explain the science of "spontaneous combustion" of oily rags? Why don't the recently oiled woodworking pieces go up in flames, or the spilled linseed oil on the top of the can (or on the floor) combined with sawdust go up either? Anyone wiped an oily finger on the side of their jeans and gone up in flames? I'm not trying to be a smart ass, and I do throw my oily rags in a metal bucket, but do you guys that experience "spontaneous combustion" smoke? Do metalwork in your woodshop? Route dado's in Chinese plywood near oily rags? Seems there must be an explanation...


When a rag is wadded up it will act as an insulator. It begins to heat up looking for oxygen and holds the heat. It's an oxidizing effect. Give it a try if you like. This towel only had about a 1/4 cup or less on it. This is also some very old linseed oil.
As far as smoking goes, I do smoke cigars but I hadn't had one for a week when this happened and I never do metal work in this shop, only in my big shop 6 miles away. This is a very real situation that can occur as you see here.


I just want to say that I got real lucky and I hope this has brought a very important issue back to the front "Burner" (pardon the pun) I had my business burn to the ground in 2000. It was vandal though but either way, a loss from fire is a very sad thing to deal with and very difficult to rebuild from. Hopefully the butterfly effect has prevented this some where down the line.

[Michael Schwartz]

In my shop, my rule is to remove all oily rags from the building within 15 minutes and place them in a sealed metal container to dry before being tossed in with regular trash.

[Yitah Wu]

As mentioned, BLO, Epoxy, and Concrete all release heat when they cure (Exothermic reaction). I know with epoxy there is a threshold quantity where you "runaway" The hotter it is the faster the epoxy reacts, which in turns increases the temperature which makes the epoxy react faster...you get the idea. I imagine the same is true of oily rags - a small oily rag isn't going to catch on fire but once you get to a certain size oily rag, it almost is guaranteed you are going to have problems. Me, I typically use a very small rag (about the size of my open hand).

A very interesting - and tragic - case happened in 2007 with another exothermic compound - plaster.

A 16 year old girl in the UK was in an art class and they decided to do a casting of her hands. They had a large enough quantity that it started to heat up. They started to smash the plaster apart but it was too difficult, and by the time they freed her, she suffered severe burns, resulting in the loss of 8 fingers.

http://news.bbc.co.uk/2/hi/uk_news/england/lincolnshire/8303246.stm

[John Downey]

Did the rag combust while you were spraying?

[Keith Christopher]

Great reminder. An I know it is extreme but when I am done with oil soaked rags, they go out back in the firepit and get lit up. I am in great fear of this happening.

[Larry Fox]

Thanks for the reminder Bill and glad nothing bad happened as a result of this. I, like Keith mentions above, have taken to buring rags that I use for solvents, BLO etc. I have a chimney starter that I use for the purpose.

A bunch of years ago my uncle - who is a heavy smoker - was cleaning paint brushes in a utility sink in his basement using gasoline (mistake #1). The heavy smoker part is relevant as he went to lite up and .... kaboom (mistake #2). Fortunately he lived but he was a mess for a while.

[Paul Ryan]

I throw out the rags after each time I stain or finish. The rags go in my burning pit it the back yard. If they go up in flames there no harm no foul. I never have had one go up though, they get burned up the next time I burn scraps or something.

[Tony Bilello]

I just hang my rags separately on the end of my steel stripping tray. Before I leave for the day, they are placed separately, flat on the concrete floor to dry overnight.
The next day they go in the dumpster and NEVER in any kind of trash bin INSIDE my shop.
I almost had a stacked stain rag fire 25 years ago and learned my lesson.

[Jeff Dege]

I have an old pair of t-shaped steel clothesline poles, in the back yard, without any clothesline. I hang my oil-soaked rags from the hooks. I used to weave them into a chain-link fence.

Out in the breeze, they're unlikely to build up heat. In contact with nothing but steel, they're not likely to cause problems if they do.

Depending on the weather, it can take a couple of days to a couple of weeks for them to cure completely.