Oil-Blackening Mild Steel

[Indianer]

Jason, I made an addition to that post... Seems like I overlooked something, mixed something up or so... I was referring to a post from Christophe de Frisselle. But I´ll leave the edited post here, because...well, why not. But thanks. That´s something that spooked me for quite a while!

[Jeff J]

Warning guys: In my -I note everything!-file on blackening, I keep a big, fat warning. Edit: Turns out, warning may be pointless...

! Attention ! Linseed oil, olive oil and such can spontaneously self-combust (even after burning onto steel )???. Archive members had their house burnt down by self-combusting armour. Instead consider using Lanolin. viewtopic.php?f=16&t=169076&p=2574521

-Indi

Edit: btw, grateful for any additions! Such as, what is "and such"... and can lanolin be mixed with lampblack for blackening? Mixing-in pigment would require an oil that fully dries, which, in turn, olive oil does afaik.

Edit: hmm....seems like I rushed something and made a mistake. After burning on a coat of linseed oil, it doesn´t seem to be hazardous anymore... shame on me...

Yes, Josh's house burned after oily rags self-combusted. No, dried oil on metal does not self-combust. It is the rags that do. But thanks for bringing this up. Store all rags in a metal lidded metal bucket. preferably, after letting them dry flat or hanging. Do not ever wad them up or store stacks. Another way to store is in a bucket of water. Get rid of them ASAP.

[Mac]

It's important to distinguish between the oils which can and can't spontaneously combust. All oils are inflammable, but only a few can ignite themselves. The oils that dry into a film are the ones to watch for. The oils that remain liquid, or just get gummy and rancid will not combust spontaneously.

It's also important to know what conditions are necessary for spontaneous combustion. A linseed oil soaked rag is dangerous when it is wadded up and can't dissipate heat, but it's harmless when laid out flat.

I leave any rag or paper towel that has been used for applying linseed oil flat on the cement shop floor or (better yet) out on the driveway till it is stiff. Just to be sure, though, I don't put it in the trash till garbage day.

Mac

[Cet]

Not just drying oils but vegetable oils will spontaneously combust as well. IIRc the culprit in Josh W's fire was an olive oil soaked arming coat.

[Mac]

This is certainly not what I thought I understood.

I've started searching for things about spontaneous combustion and olive oil, and while I have found several assertions, I've not yet found anything with numbers. Can anyone link to something with hard information?

Mac

[Seaan O'Hagan]

I suspect I can avoid the issue by doing it all outside and chucking the rags in a campfire

[Josh W]

Yes, on August 28th, 2005, my nice green gambeson was slung over a chair at my kitchen table in my house. I had just finished polishing my harness, which was spread out all over the living room floor, when my wife decided to take us to visit her parents a couple of hours away in Leavenworth.

The gambeson, which had olive oil and sweat on it, apparently spontaneously combusted.

I remember when the fire investigator told me; I didn't believe him at first. I guess the environmental conditions have to be just right in terms of humidity, etc.

A few years later, I found myself in conversation with an insurance adjustor, and the topic came up. He mentioned that the case had made it into his industry literature as one of the confirmed cases.

[Ckanite]

It's important to distinguish between the oils which can and can't spontaneously combust. All oils are inflammable, but only a few can ignite themselves. The oils that dry into a film are the ones to watch for. The oils that remain liquid, or just get gummy and rancid will not combust spontaneously.

It's also important to know what conditions are necessary for spontaneous combustion. A linseed oil soaked rag is dangerous when it is wadded up and can't dissipate heat, but it's harmless when laid out flat.

I leave any rag or paper towel that has been used for applying linseed oil flat on the cement shop floor or (better yet) out on the driveway till it is stiff. Just to be sure, though, I don't put it in the trash till garbage day.

Mac

I almost started a fire a while back that way figuring all those things are just rumors. I had been throwing my linseed oil rags in the plastic garbage cans for months, you know the same can that held all of my other wood scraps. Till one day I smelt burning plastic. I searched all over the house for the smell till I went to the shop. I found the sidewall of the can just starting to melt and the room was full of fumes, no smoke or flames yet though. Since then, I keep a sealed metal container in the shop that I put all of my rags into for a few days before disposing of them.