How do you dispose of BLO rags?

[Jeff Skory]

Hi All,

Question of the week:

BLO is known for spontaneous combustion if left on rags (and presumably paper towels). As such care must be taken in disposing of them. The can recommends letting them dry completely out in the sun. Well, it's winter around here and there's not a whole lot of sun or warmth.

I have been putting the used paper towels in a zip-lock bag filled with water and with the air (aka oxygen) squeezed out. I am assuming this should be sufficient.

How do you dispose of your BLO soaked rags?

[Michael Perata]

How do you dispose of your BLO soaked rags?

I have a small 1.5 gallon lidded trash can that I keep half full of water.

True Story Time:

1989 I was building two custom homes in Gilroy, CA and one of them was in the process of having the cabinets stained. The painters were using DuraSeal and when they finished on Friday, simply threw the rags along the base board in the dining room.

Sunday I had occasion to show the other house, completed at this time, to a couple of buyer's. After I finished showing them the house, I invited the couple to take a look at the unfinished house.

I open the entry door to find the house filled with smoke. Immediately I went looking for a fire. I could't find one, but knew something was causing the smoke. Called 911 and went back into the house trying to find out where the smoke was coming from.

Walked into the dining room and almost fell through the 4' x 4' hole that was neatly burned into the subfloor and through the floor joists. No flames, just a smouldering fire that had probably been burning since Saturday and had slowly burned itself through the floor. It was also hot enough to have melted an aluminum ladder that was also stored along the base boards in the dining room. Fortunately the house was sealed so tightly the fire was oxygen starved and didn't have a chance to flame-up.

Yep, spontaneous combustion caused by the painters leaving their rags unprotected. The painting contractor was quite upset about having to pay to have the entire house interior washed, primed and repainted, and the floor repaired. He cautioned his painters to not throw oily rags willy nilly in the houses anymore. So what did they do with the rags? They threw the rags out against the rail fence between the houses and promptly burned 15' of new fence. Sigh!!

[Kent Cori]

Jeff,

I have this handy bush right outside my garage shop. I just spread the rags or towels out flat on the bush and let them dry. I keep them there until I take out the trash for weekly pickup. By that time they are good and dry so I just put them in the can as I wheel it out to the street.

[Dave Anderson NH]

Be very careful with rags containing BLO, tung oil, oil based paints, and an other oil containing finishing product. The picture below is of the shop of a professional woodworker friend of mine. He had returned from a hard day selling his products at the Sunapee Fair, a 9 day event run by the League of NH Craftsman, was having his dinner and smelled smoke. One of his employees had been working in the shop during the day and had left some rags with BLO in a pile in the finishing area. Unfortunately the phone line ran to the house via the shop and had been melted. The next house is a 5 minute RUN up the street and the volunteer fire department is a 10 to 15 minute drive away. The 200 foot high flames were spectacular enough to merit a color front page picture in the Concord NH daily newspaper.

Personally I put all drying oil and solvent filled rags in my woodstove and burn them.

[Terry Quiram]

I to had a house fire as a result of oily rags left in a pile. Lucky that the fire was contained to one room, but smoke damage through out the rest of the house. I have a metal trash can outside the shop, no lid. All rags/towels and gloves go into the can! Emptyed weekly.

Terry

[Mike Evertsen]

outside in a can noway do I leave stain rags inside even the water base stain rags go outside,,,,

[Ken Fitzgerald]

Jeff, I have 2 chain link gates opening onto my backyard. I hang all of my finishing rags on those gates for a few days until they are dry. Once they are dry they are placed in the trash.

[Joe Bourbois]

I use empty metal paint cans I buy from Home Depot. Put the rag in and fill it with water.

[Rob Littleton]

Guys,

what kind of quantity are we talking about here. (kinda nervous now)

I use BLO on a rag but I really only wrap up one finger in the rag and then put my finger in the top of the can, turn it and wipr the bLO on the end of my finger, onto the work.

Is that enough to be concerned about?

cheers

[Jim Becker]

I hang the rags (really paper towels) on a spike set into a wooden retaining wall so they can blow in the wind. This spike is away from the shop.

And yes, Rob, even a little oil can generate a lot of heat when you least expect it. Dispose of the rags/towels properly.

[Tyler Howell]

Guys,

what kind of quantity are we talking about here. (kinda nervous now)

I use BLO on a rag but I really only wrap up one finger in the rag and then put my finger in the top of the can, turn it and wipr the bLO on the end of my finger, onto the work.

Is that enough to be concerned about?

Rob !!!

Outside:mad:

One of the guys from work lost his car and garage from Danish Oil rags. Insurance came through.
Another guy from work wanted a bigger garage and new car. Danish Oil came through.

[Ron Jones near Indy]

Jeff, I have 2 chain link gates opening onto my backyard. I hang all of my finishing rags on those gates for a few days until they are dry. Once they are dry they are placed in the trash.
I also do this. Have had no problems.

[Jeff Skory]

Looks like this thread might save a couple of basements. :)

I am surprised at just how many of you have direct experiences with these fires. Thanks for sharing those with us.

So, to recap what I have heard so far:

1) hang rags outside to dry (far away from structures).
2) put into covered metal cans that are half-filled with water.


Question: Why wouldn't these rags self-combust outside while hanging up to dry - or sitting in an open metal trash can like Terry has? That would make me a bit nervous as well.

And I think my method of using a ziplock bag filled with water may not be the safest either. If the bag breaks and leaks out the water I could be in trouble.

Thoughts?

[Jack Diemer]

Light on fire and throw them into the neighbors yard.

[Jeff Skory]

Light on fire and throw them into the neighbors yard.

LOL! :D No use waiting for it to do it on its own, huh?

[John Christiansen]

Light on fire and throw them into the neighbors yard.

Well except for the neighbors yard part, this is the most sensible suggestion for those that are able to.

I have both an incinerator and a fire pit in my yard. I just walk over to one of them, light the rag up and toss it in. No muss, no fuss, job done.

[Jason Roehl]

Looks like this thread might save a couple of basements. :)

I am surprised at just how many of you have direct experiences with these fires. Thanks for sharing those with us.

So, to recap what I have heard so far:

1) hang rags outside to dry (far away from structures).
2) put into covered metal cans that are half-filled with water.


Question: Why wouldn't these rags self-combust outside while hanging up to dry - or sitting in an open metal trash can like Terry has? That would make me a bit nervous as well.

And I think my method of using a ziplock bag filled with water may not be the safest either. If the bag breaks and leaks out the water I could be in trouble.

Thoughts?


The problem is not with just any solvent-based product. The problem is with any finish that contains a drying oil such as danish oil, tung oil, walnut oil, BLO, and others. These oils oxidize (react with oxygen) in the curing process, which is a chemical reaction that generates a fair amount of heat. Spread over a project, it is not a problem, but when you soak a rag in it and crumple it up, the heat is somewhat trapped by the rag, with a plentiful supply of oxygen still available. Since the heat has no way to escape, it builds up to the combustion temperature of the rag and/or remaining solvents.

Your plastic bag method would continue to work, as there is no oxygen available to the rag. But, if the bag ever leaked out....

Standard method of disposal is to partially fill a metal container with water, put the rags in there, and put on a tight-fitting lid. Laying or hanging them flat works also. Some would be understandably nervous about doing this in their shop, but as long as they are in a single layer laying flat or hanging, there's really no danger of heat building as they dry. (I'd still do the trashcan thing, or lay them outside...winter weather is fine).

BTW...Not all painters are that ignorant.... :rolleyes:

[Steve Clardy]

Light on fire and throw them into the neighbors yard.

Ha Ha. Best response yet!!!
:D
Mine go in the wood stove. Steve

[Michael Perata]

BTW...Not all painters are that ignorant.... :rolleyes:

Agreed. Fortunately/unfortunately I live in an area with a significant population that does not use English as their first language. Most are very hard workers who do high quality work but often they are not aware beyond what their immediate training requires and disposing of flammables was not immediate at the time. Now they know.

[Tom Sontag]

I usually hve a couple paper towels and simply light them inside a galvanized bucket or on the some dirt (outdoors!) when I am finished. The firebug in me likes it this way. Boy, that oil burns hot.

[Zahid Naqvi]

My noviceness (if there is such a word) at woodworking requires further explanation. What is BLO? and what kinds of finishing products should I be carefull about? I mostly stick to water based paints and finishes (so far) because of ease of application, but I do have paint thinner and lacquer thinner type stuff in my garage.
If there is a risk of combustion, as stated above, the best option would be to just burn the stuff instead of drying.

Zahid

[Greg Wandless]

Jeff,

I flatten mine out and drap them over the edge of a metal waste can for a couple of days, then out with the trash ASAP.

Greg

[Dave Anderson NH]

As others have stated, regular solvents like paint thinner, naptha, turpentine, and lacquer thinner are flammable but not a problem for spontaneous combustion. They will burn and care should be exercised with them around open flames, and in any situation where you could get a concentration of vapors high enough to have a spark set them off in the air.

What we are concerned with is the insidious effect of drying oils like BLO (Boiled Linseed Oil), walnut oil, tung oil, Danish Oil, and a few other less common oil based products. These oxidize in contact with the air, and when they are crumpled up in piles or in balls, they begin to generate heat from the oxidation. This heat builds rapidly until it reaches a point where the oils and the paper or cloth they are carried in reach their ignition temperature. Depending on the amount of oil in the cloths or papers and environmental conditions spontaneous ignition can occur anywhere from as little as 15 minutes to as much as 12 hours later. If you want to prove this, take some rags or papers and wet them with one of the drying oils and crumple them up in a metal pail outdoors. Do this well away from flammables and your house. Then jsut sit down in a chair with a book and wait. You will be amazed.

You must have seen the picture I posted earlier in this thread. My friend was lucky not to lose hishouse which was 75 feet from the shop. Don't worry though, he came out all right in the end. If you look at the top of the photo carefully, 65 of his friends got together 2 months later and build him a new shop in one very long and tiring weekend.

[Jim Young]

Here is my answer. I just hang the rag on my jointer handle till it dries. This wouldn't work if you use lots of rags.

[Chris Padilla]

I find it curious that no one attempts to WASH or CLEAN their soiled wiping rags. I just toss mine in the washer machine.

[Jim Becker]

I find it curious that no one attempts to WASH or CLEAN their soiled wiping rags. I just toss mine in the washer machine.

In my case, it's because I use disposable towels, not cloth. They are thick, absorbent and inexpensive. While we don't use many paper products in the house as a rule, for this purpose, I prefer the paper. (I buy the Scotts "rags in a box" in the blue and yellow box from the big box store)

But to your point, even if you are going to wash them, unless you thrown them in and put the wash cycle on immediately, you can still have the fire hazard.

[Jim Young]

I thought the paper towels would leave lint or whatever that stuff is. I'll have to try them if they work. If they work for oil then they should work for other finishes.

[Howard Acheson]

You can spread oily rags out inside your shop. The key is to allow air to freely get to them. I have a clothesline and I just drape them over the line until they dry. Once they are dry, they can be discarded in the normal trash.

The reason I don't like using water filled cans or similar water solutions is twofold. One, when you remove the oily rag from the water, it is still capable of combusting when the water dries out. In other words, soaking the rag in water prevented the air from allowing the oil to cure. Take it out of the water and the air allows the oil in the rag to begin to cure which generates the heat. Second, the water you soaked the rags in is now considered a hazardous chemical waste and should not be discarded just by throwing it out.

Seems to me that the best option is to just hang them up either outside or inside.

[Jim Becker]

I thought the paper towels would leave lint or whatever that stuff is. I'll have to try them if they work. If they work for oil then they should work for other finishes.

The towels I'm using (as described above) are lint-free and quite absorbant. I use them for both flat-work and for finishing turnings on the lathe.

[Jeff Skory]

You can spread oily rags out inside your shop. The key is to allow air to freely get to them. I have a clothesline and I just drape them over the line until they dry. Once they are dry, they can be discarded in the normal trash.

The reason I don't like using water filled cans or similar water solutions is twofold. One, when you remove the oily rag from the water, it is still capable of combusting when the water dries out. In other words, soaking the rag in water prevented the air from allowing the oil to cure. Take it out of the water and the air allows the oil in the rag to begin to cure which generates the heat. Second, the water you soaked the rags in is now considered a hazardous chemical waste and should not be discarded just by throwing it out.

Seems to me that the best option is to just hang them up either outside or inside.

Howard,

Makes sense. But doesn't it make you a little nervous having those rags IN your workshop? Any idea on whether rags or paper towels present more of a danger? And how long does it take to dry out?

I would think that the BLO that has soaked into the wood would pose almost as much of a danger but apparently not. Maybe I can find some more indepth info at the manufacturer's site. I'll have to look later tonight.

[jim barter]

Jeff / The reason that the rags will not spontaneous combust when hanging to dry is the decomposition of the organic material is slowed to a crawl.There is no chance of the decomposition generating heat by being confined in a ball or just laying on itself.Spontanous combustion is the decomposition of organic substances. They generate heat without the use of oxygen.This heat in turn will ignite the combustible material such as the rag.I do fire investigations and have been to several shop fires and dryer fires.Its amazing how many people will wash and dry rags from the shop or even the rags from polishing the floor with wax(such as min wax)
I personally have a pail with water and it sits next to my lathe on the floor and this is where all rags go .

[Jeff Skory]

Jim,

Being a fire investigator you must be QUITE familiar with all of this. I am quite new to woodworking myself. I knew about the danger of BLO but never really had a reason to use it before. Now that I am starting to finish pieces I am building I am quite nervous about this whole mess.

Not having a wood stove like some of the guys I tried burning the paper towels and rags in a small grill I had laying around. Not the most convenient thing to do in the middle of the night. And the neighbors are probably going to become suspicious. :rolleyes:

So now I am placing them into a metal paint can half filled with water. But I don't feel comfortable keeping that in my shop. From the sounds of it you not only keep it in your shop but being a pail is it open on top? Is this completely safe? Is it safe to keep the metal paint can half filled with water in the shop?

Thanks for your advice.

[Dale Thompson]

As others have stated, regular solvents like paint thinner, naptha, turpentine, and lacquer thinner are flammable but not a problem for spontaneous combustion. They will burn and care should be exercised with them around open flames, and in any situation where you could get a concentration of vapors high enough to have a spark set them off in the air.

What we are concerned with is the insidious effect of drying oils like BLO (Boiled Linseed Oil), walnut oil, tung oil, Danish Oil, and a few other less common oil based products. These oxidize in contact with the air, and when they are crumpled up in piles or in balls, they begin to generate heat from the oxidation. This heat builds rapidly until it reaches a point where the oils and the paper or cloth they are carried in reach their ignition temperature. Depending on the amount of oil in the cloths or papers and environmental conditions spontaneous ignition can occur anywhere from as little as 15 minutes to as much as 12 hours later. If you want to prove this, take some rags or papers and wet them with one of the drying oils and crumple them up in a metal pail outdoors. Do this well away from flammables and your house. Then jsut sit down in a chair with a book and wait. You will be amazed.

You must have seen the picture I posted earlier in this thread. My friend was lucky not to lose hishouse which was 75 feet from the shop. Don't worry though, he came out all right in the end. If you look at the top of the photo carefully, 65 of his friends got together 2 months later and build him a new shop in one very long and tiring weekend.

Dave,
I could not have said it better or agree with you more. Piles and "bunches" will BURN for the reasons which you listed!

Dale T.

[nic obie]

I do the same as Howard A. does, spread them around flat on the floor or drape them over metal in a spot with good air circulation till they get stiff. 24 hours is usually enough.

[Pat Salter]

Our clothes line is closer to the shop than the house so I use it. then they disappear on tuesdays (garbage pickup day). I also have a garden shed that is about 60 ft. from the house and the shop. That's where I keep all that stuff when I'm not using it. I'm actually hoping that it will go up. I'd like to build a bigger/better one! then I'll get one of those cheap small metal ones for my paints/stains etc. I'm not comfortable with the stuff in the shop.