Cautionary tale snipped...

> On 20 Nov 2018, at 01:42, james rich  wrote:
> 
> James ,I almost burnt my 71 Blazer to the ground by leaving some rags still
> damp with Watco in a 2 gal. bucket in the back . At the time many years ago
> I was working on a side job before work ( was working swing at the time )

I’m not a one to be overly scared on the ‘what if’ front, and I only ever use a
steel waste bin for used cloths, but I’m intrigued by this.  My understanding of
the chemistry is that oxidation of the oils is taking place to produce the
polymerisation, and this is an exothermic reaction.

At one end of a scale is a few drops of oil on a cloth in an ambient temperature
of notalot.  I don’t expect any issues to arise.

At the other end is a gang of finishers with a quantity of well soaked cloth,
folded into wads to incorporate air/oxygen anf placed in to a nice warm dry
place without draughts to help the heat build up.


Somewhere along the line is the critical mass and point of combustion.  Do we
have any chemists who can put some numbers to all of this?   What weight of oil
at what ambient temperature is needed before critical mass is reached?

Typically, I use a single square of cloth, no more than 4x4 inches, to apply
oil.  I may use an 8x8 to wipe off.  No more.   Whilst I’m conscious of the fire
risk, I’m not yet paranoid about oily rags.


For completeness of disclosure, there are 2 smoke alarms and both CO2 and water
extinguishers in the workshop.

Richard Wilson
In Northumberland, where winter can be seen sitting offshore.