View Full Version : A question about the flammability of mediums

09-09-2001, 08:49 AM
OK, this might be a "duh for dumb" question, but...

I've read a lot about people's concerns over medium-soaked rags' flammability and how to dispose of them properly so as to avoid a disaster.

Am I correct in understanding that, if left attended, rags soaked with linseed oil will just spontaneously combust without the need for a spark (like a lit cigarette or something)? If I just toss my used rags or paper towels in a bag or plastic pail, they will just catch on fire because of exposure to oxygen? How is it that we can paint and not have fires just burst out in our hands? Sorry if it sounds sarcastic, it's not my intent- it's a straight question. :)

I generally also just leave what's left of my medium in the palette cups attached to my palette after a painting session, and dispose of it later. Am I courting disaster by doing this? Also isn't burning used rags a tad more dangerous (fumes, etc)?


09-09-2001, 07:18 PM
3 things are needed for spontaneous combustion: an ignition source, fuel and oxygen. With oily rags the oil oxidizes, a process that generates heat (exothermic reaction). Heat trapped inside wadded up discarded oily rags causes the reaction rate to increase, producing more heat and... voilą! Spontaneous Combustion!

09-09-2001, 08:56 PM
OK, so now we have the answer thanks to the wonders of Chemistry via lcg. The next step...

Instead of a closed metal container to toss the rags into, is it ok to throw them into a pail of water? Will that stop the oxidation?

Also, IS there any danger in leaving an open container (small metal palette cup) uncovered after a painting session?

09-09-2001, 11:01 PM
Originally posted by babsalaba2
concerns over medium-soaked rags' flammability and how to dispose of them properly so as to avoid a disaster

Hi, Barbara - When I was wondering about this same subject, my husband recommended that I use an oily waste can, a common item in car repair shops. I had seen oily waste cans for as much as $80 in an art supply catalog, but he found me one for $19.99 from Harbor Freight (www.harborfreight.com). It's item #37506-5VGA, 6 Gallon Oil Rag Can. These cans are nice to have because if the rags do combust, the can will contain the flames till the fire burns itself out. The lid is heavy and the waste compartment is airtight, which also cuts way down on turps and linseed oil odors in the studio. There's a foot pedal to operate the lid. I've included a link below for anyone who is interested. - Brie


09-10-2001, 08:15 AM
Don't get too complacent whatever the "chemistry".

In my school studio:
I was experimenting with linseed oil - the canvas was soaked with it. Unstretched pinned to a wall. No oily rags about, all "flammable" mediums locked away in a fire department approved cabinet.

Studio fire in the middle of the night (water damage to several other student's studios. Mine totally destroyed along with everything in it.)

Only explanation by Fire Department inspector - spontaneous combustion of oil soaked canvas. They said I had done everything "right" - except for my over-enthusiasm with my would-be masterpiece.

I don't use linseed oil at all any more. Totally neurotic about fire. I put paint stained/turpentine rags in a bucket of water.

09-10-2001, 10:03 AM

Good God! That's terrible. Thank goodness you're ok. Since my studio is in the house, I am awfully concerned about this. I don't generally use a LOT of linseed oil, but I do like to have it on hand. What medium do you use now?


Thanks for the link. I also saw the exorbitantly priced can and thought that there has to be a better way, and you found it, thanks! :)

Maybe I'll stick to liquin... I've been considering trying out one of the gel mediums too, like Oleopasto, Wingel or Grumgel. We;ll have to see.

09-10-2001, 10:05 AM
certainly recommend a metal, lidded can for oily rags.

every night i pour out my solvents & mediums into lidded glass containers. i am scared of fire and never leave solvents unattended. odorless is less volatile than turp and can probably be leftovernight, but i take no chances.

then again, i wash out my brushes after every session, too. so maybe i'm anal.

09-10-2001, 10:57 AM
Just last Friday, a man nearby was refinishing wood at his daughter's house, and left a pile of oily turpentine rags on the deck. They combusted, and within minutes, an entire condominium complex was totally destroyed. It was not a pretty sight.