[DavidF]

I was reading the back of a bottle of French Polish (see! some people really do read instructions) and it warns that the used cloths "should be disposed of safely as under some circumstances auto-ignition can occur".

Does anyone know what these "circumstances" are?

I live in South Africa which is a pretty warm place (not at the moment, it's pouring with rain). Presumably ambient temperature would be a factor.

How should they be "disposed of safely"?

David

 

[Al Robins]

Welcome to the Forum David....the reason that is written as a warning is a thing called spontaneous combustion.....(suggest you hit Wiki for the correct spelling) . If you have finished French Polishing and toss the old rag into a plastic bag, a fire can start without the presence of a flame. The heat generated by the metho and the bag is enough to cause ignition under some circumstances. Regards.....AL

 

[newwoodworker]

The way I deal with my rags when done is to lay them flat on the concrete with a rock holding it down as long as you dont pile multiple rags on top of each other and the rag has plenty of air circulation passing over while it "drys" it should be fine I have never had one catch fire but maybe someone else will have a better solution as mine may not be correct.

 

[Swallow]

For myself I never use rags twice and after I'm done with one it goes straight into the wood stove that heats my shop winter spring and fall which is most of the year here in Canada. During our two weeks of summer I just dump them into the fire pit outside. Replacing rags is cheap, replacing a shop, a garage or a house is NOT so I just get rid of them.

 

[bobj3]

Hi Guys

They sale a safety can just for that job, it's a 5gal. metal can with a cam loaded lid on it and you step on foot opener and the lid pop's up and you put the rags in the can, many paint shops have them...and it's a must have item in many shops,,(fire codes) if you want to see a picture of one just ask and I will post one..

here's a link to one
Amazon.com: Justrite 09100 Oily Waste Can 6 Gallon: Industrial & Scientific
========

 

[jaydubya]

As a volunteer firefighter, i have actually fought a housefire that was started by stain rags thrown in a bag that spontaneously combusted

 

[kp91]

linseed oil is not not allowed on our US flag vessels because of the auto ignition hazzard. Ultrafine steel wool too.

It's amazing what can start fires.

 

[sourdough]

BLO and steel wool deadly combo!

KP91 is dead on right. I have had linseed oil and fine steel wool burst into flame on two occasions!! I am a very careful dude with that stuff now!!
One time I was actually buffing BLO into a project with 0000 steel wool and it flamed up in my hand! Yikes!:wacko:

 

[DavidF]

That's scary !! Unlike Swallow we have 2 weeks of winter and the rest is summer.

Steel wool surely cannot spontaneously combust if it's lying on a shelf, can it? I've got a large wad of 0000 steel wool on the same shelf as all of my thinners, french polish, paints and varnish.

Was KP91's autoignition caused by friction?

I don't even have a fire extinguisher!!

 

[woodnerd]

Any type of finish that "cures" generates heat while curing. When you take finish-soaked rags and pile them together in a tight area, the heat can reach the flash point and ignite.

Lay them out on a board outside the shop. Once they cure, they're no longer a threat.

 

[kp91]

That's scary !! Unlike Swallow we have 2 weeks of winter and the rest is summer.

Steel wool surely cannot spontaneously combust if it's lying on a shelf, can it? I've got a large wad of 0000 steel wool on the same shelf as all of my thinners, french polish, paints and varnish.

Steel wool has a high iron content and a large surface area. The surface area is the hazard. Metal dusts like aluminum and iron burn relatively easily when in presence of a flame because they have an extremely large surface area to react with the oxygen. Iron also has an annoying problem of being pyrophoric when in contact with certain chemicals in a low oxygen environment. When oxygen is reintroduced, then it can ignite. That is why you let things dry out in an open atmosphere, and don't store them in a ziploc bag.

Also, rusting steel wool can generate it's own heat. It doesn't take a lot of energy to start a fire in steel wool, you can do it with flashlight batteries. If you have a nice clean pad of steel wool, you should be fine. If it's getting rusty, or soaked with a natural oil that also generates heat while it decays (aka linseed oil) you can have an ideal firestarter.