Steel wool can spontaneously combust - here's the reason

Remember when I posted that I was filling possible critter entrance holes in the cab of the truck?



I had no idea how they were getting in.



I was using fine steel wool, which was working just great fitting into any small spaces.  Then it started smoking and seemed to spontaneously start on fire.  Scared the heck out of me!  I thought at first it was a live wire that the steel wool touched.

This is what I wrote on March 16, 2016:  "Oh, yeah, and I've caught six mice.  Some in The Palms, some in the engine.   I've pretty much spread snap and glue traps across the inside of the engine and in front of and under my driver's seat.  They get in through the engine into the driver's foot well, but I can't find the hole they are using.  I got some fine steel wool and stuffed it into areas that looked like they might be openings, but the steel wool caught fire and I threw it outside quickly.  Luckily nothing ignited except for the steel wool.   I don't see any exposed wires up there, so I don't know what caused it to ignite.  Spontaneous combustion?   Scared the heck out of me, though, and I won't be doing that again."



Shortly after that post I received an e-mail from Andy Baird with the answer to why my fine (#0000) steel wool started on fire. This is what he said:

"Barbara--steel wool can spontaneously combust, especially if it gets even slightly damp. The finer it is (e.g. #0000), the more likely this is to occur.

http://fretsnet.ning.com/forum/topics/spontaneous-steel-wool-combustion

The reason: rusting, which is oxidation, gives off heat, like any oxidation reaction. Normally you don't have to worry about this--your RV frame isn't going to catch fire, because the amount of heat generated is small compared to the mass of metal. But rusting occurs at the surface of a piece of steel or iron, and thanks to its fine filaments, steel wool has a huge amount of surface area in a small volume. Heat can build up as it rusts, and you've seen the result. Please warn your readers to use copper "mouse mesh," not steel wool."

I clicked on the above link which he also provided and promptly put my #0000 Fine steel wool outside, ready to take to the dumpster.  I didn't want it in The Palms.  But I do have some #3 Coarse steel wool which I'm keeping.

Thanks, Andy!

I meant to post this right after I got that e-mail from Andy, and started a post that turned into a draft, and I forgot about it. I just found it, and wanted to be sure to pass along this info.  So, if you have that super fine steel wool around somewhere, be advised that it can be dangerous and can actually start a fire.  Handle and store it with care.

My plans for the summer have changed and I'm working on some photos now that I'll post soon.

In the meantime, have a wonderful day, everyone!