Danger of oily rags

[Doug Hobkirk]

Is one rag dangerous or is it when several are thrown together? I don't want to burn my house down!

I am doing some varied refinishing, and I frequently leave rags that have been soaked (with wipe-on poly or shellac or oil stain or paint) that I want to reuse in 4-8 hours for the second or third coat. I spread the rag out but leave it in my garage during this time. If I have more than one rag in active use, I keep them apart. After I'm done, I spread the rag out outside to dry before I trash it.

Am I being safe? Should I seal the rags individually in an air-tight container (in Tupperware? Ziploc bag?) during those 4-8 hour intervals?

[Jim Knishka]

NO! One rag is enough -it's about lack of circulation. Many years ago when building our first house, we were finishing our own woodwork we stained late one night and were tired, and came back the next morning to find the icecream bucket of rags smoldering. Another hour or so we would have lost the house. This was less eight hours. Drap them to dry, or put them in water and write them off.

[Neal Clayton]

yeah, don't contain them, that's what causes it.

when i was in college working at a hotel a waitress got burned that way, picked up a bundle of napkins in the kitchen and by the time she got to the washing machine they caught fire in her hands.

drape them separately over something and they'll be fine, do not stack them or otherwise enclose them in anything.

[jerry nazard]

My first, and hopefully last, experience with this was 30 years ago. I was using a felt chalkboard eraser to apply Watco danish oil. Walked into the shop one morning and reached for the eraser - it was almost smoldering hot! Lesson learned and not forgotten.

Best!

-Jerry

[Jason Roehl]

No need to be afraid of anything with 'oil' in the name, though. What you need to be careful of are products that contain oils that oxidize when they cure--BLO, tung oil, danish oil, etc. Mineral spirit-based stains won't do it (like Minwax), motor oil won't, veggie oil won't, mineral oil won't, because none of those cure or oxidize.

And, actually, the "approved" method of storage until disposal is to put them in a metal can filled with water and put a (metal) lid on it. If you drape the rags over something to dry, do that outside. In the shop, someone else could come in, cause a draft, and that rag may end up on the floor in a heap--then you're out a shop.

[Per Swenson]

Related Anecdote,

And remember folks ignition is a funny thing.

I don't mean funny, ha-ha, I mean funny as you never know.

A Harry the homeowner neighbor fella, and good friend besides,

decided to polyurethane his hardwood floors. Rented a floor sander,

Did the job and applied the poly.

The poly never dried. It was late winter, cold wet damp and crappy.

The floor was like one of those glue traps for mice.

Mind you, it was no bigger then 12 x 16.

He rerented the floor sander, it being only 12 x16, the finish came up

and in the bag in 10 minutes. 10 minutes. At 11 minutes I smelled something funny. Asked him to take that bag outside quickly.

Speakin of funny, it was the look he gave me, the you know ,

whatsa freakin mhatta wuth you? tough guy look, (spelling for NJ accent)

That was when the bag ignited.

It smoldered and burned outside in a snowbank with light flurries

for close to 12 hours.

Per

[Lee Koepke]

good story Per

I use a piece of closetmaid shelving to spread my rags out on. before i leave the shop, i pick up the shelf and put it outside.

Just like any other safety feature in the shop, common sense and good habits go a long way.

I hang ALL my rags on that shelf regardless of what I used, thus maintining the habit, and limits the one time I may forget to properly store my BLO rag ...

[Cliff Rohrabacher]

No need to be afraid of anything with 'oil' in the name,

Perzakly so.

What you need to be careful of are products that contain oils that oxidize when they cure--BLO, tung oil, danish oil, etc.

Perzakly so.

My method is the most scientifically well engineered solution known to man.

I invoke a highly sophisticated application of the earth's gravitational field and the atmosphere to randomly isolate each such rag from any other while utilizing the molecular power of Brownian motion in gases that occur naturally to obtain convection dispersing the heat.


I toss 'em on the floor with the saw dust and scraps and junk. Then days or weeks later when I'm sick of tripping over the accumulated junk I get a steel rake and a broom and a snow shovel and put all that crap in a heavy duty garbage bag and set it on the curb (OK, I don't really have a curb) for the townies who come by and for reasons I can't understand they seem to want the stuff and collect it.

[Mike Monroe]

Firefighter Mike here. Few years back had a local guy burn down his garage because he didn't believe the warnings on the Watco Danish Oil can. It was a detached garage and we were able to save the house, though it was touch and go there for a little bit. The guy had quite a few combustibles in the garage; kerosene, petrol, ammo, gun powder, etc…

Bottom line, don’t risk a fire. Deal with oily rags appropriately every time.

[Jesse Cloud]

I've got a 25 cent solution for ya...

I tie a piece of string about 3 feet long to one of the outdoor utility pipes (doesn't matter what, just so it will hold the string) and the other end to the trash can about three feet away. Use clothespins to attach oily rags, one per pin. They dry in a few hours and then I toss the rags into the trash and untie the trash can end of the line.

For rags that will be reused in a few hours, I put them in a special air tight container, aka old glass jar with a lid. They don't dry out and are ready to go for the next use. One hint, don't use a jar that still smells. I once had to redo a project that smelled of pickles.

[Rick Levine]

This is why I invested in one of these:
(A safe, relatively inexpensive way to store the rags until I can dispose of them safely)

[Mike Henderson]

Let me point out that there's two kinds of oil - drying oil and non-drying oil. The dangerous stuff is the drying oil because it generates heat when drying.

The red containers don't prevent oily rags from catching fire (unless you fill it with water or it's air tight), they only contain the fire. They need to be emptied often (before the rags catch fire). It's much safer (in my opinion) to dry the rags flat somewhere.

Mike

[Howard Acheson]

The most dangerous rag is one that has been wetted with boiled linseed oil or a finish containing a high percentage of linseed oil. These finishes are the oil/varnish finishes like Danish Oil, Tung Oil Finishes or a home brew oil/varnish. These rags should be spread out and allowed to dry. Once dry they are no longer dangerous and can be discarded in normal trash. It's the slow polymerization of linseed oil that leads to heat being produced over a long period. Fast evaporating solvent/thinners are not dangerous.

Rags with oil based varnish or poly varnish are not very dangerous as they do not produce much heat as the finish dries. Rags that have thinners like mineral spirits, naphtha, acetone, lacquer thinner, etc are not dangerous. Nor are rags that contain lacquer, shellac, or waterborne finishes.

But, let me point out, that rags with finishes on them should not be stored for more than an hour or so. Oil based and waterborne finishes cure by oxidation or the interaction of the finish with oxygen. Once exposed to oxygen the finish starts curing and will continue--but at a reduced rate--even if stored in a seal jar or package. It's best to use a fresh applier for each coat if you can't get back within an hour. I use non-embossed shop paper towels for applying wipe on finishes so it cheap to just discard them after each use.

[Tom Henderson2]

Is one rag dangerous or is it when several are thrown together? I don't want to burn my house down!

I am doing some varied refinishing, and I frequently leave rags that have been soaked (with wipe-on poly or shellac or oil stain or paint) that I want to reuse in 4-8 hours for the second or third coat. I spread the rag out but leave it in my garage during this time. If I have more than one rag in active use, I keep them apart. After I'm done, I spread the rag out outside to dry before I trash it.

Am I being safe? Should I seal the rags individually in an air-tight container (in Tupperware? Ziploc bag?) during those 4-8 hour intervals?

There have been a lot of responses, and a lot of techniques shared, but I don't think anybody addressed your specific question about how you are handling it.

It sounds to me that you are spreading the rags out, allowing good air circulation, and keeping the rags separate. That sounds like safe practice to me.

I have typically draped the rag over the lip of the trash can. They aren't touching anything but the barrel and dry out pretty quickly.

The risk, as I underestand it, is when there isn't enough air circulation, as when rags are wadded up, or worse, many rags are wadded up in the same container. Heat is generated, and combustion can occur.

-TH

[Eric DeSilva]

I've got a basement shop. I posted a similar thread a few months ago, and decided to take things seriously. Now, whenever I'm done with a finish rag, I step outside into the concrete stairwell, and use one of a little spring clamp to clip it to the metal rail. When I do that, I pick up the rag I left out there the last time and pitch it...