Conference noted::woodworking_and_tools

When I bought a can of Watco at Woodworkers Warehouse the
sales clerk took special pains to ask me if I understood
about spontaneous combustion.  It must be a real problem
with that formulation.

My understanding is, any time it dries out, it can go up.
I put my rags in the fireplace and burn them right away.

The problem is that the oil generates heat as it dries.  If oil-soaked
rags are thrown in a pile, the heat can't escape fast enough and combustion
can happen.  Once the rags are dry there is no longer any danger.  One
common method of dealing with the problem is to spread the oil-soaked
rags out in single layers until they're dry.  Another is to put them
in a covered metal trash can.

-Hal

    Spontaneous combustion is a danger only when you bundle the oil soaked
    rags, I simply drape them  singley over a wooden dowel and let them 
    dry out.  
    
    Brian
    

	As a previous note mentioned, it's the drying of 
the oil that can cause the fire.  Some oil finishes 'dry'
through a chemical reaction that produces heat ('exothermic')
and the heat can start a fire rather easily.  This used to
be 'common' sense, back when all oil finishes were that type,
before we got into plastic stuff like polyurethanes.  Nowadays
it's not well known any more, and I've read numerous tales of
folks working all weekend on their brand new (remote) house,
applying all the finishes to all the exposed expensive wood...
they go back to the old house for a shower and rest....and 
return to a pile of ashes the next day, as they'd left a pile
of oily rags in one room.

NOT ALL OILS ARE LIKE THIS.  Walnut oil and mineral oil give
you no problems.  In general, though, you should remove ALL
your finishing materials from the house/garage/whatever, and
leave them some place fire can't hurt.  Don't forget the paper
towels you wiped a spill up with, either.

    Great information  - but - how about some comments on one particular
    question ..... if I rinse the rags with water - I mean really soak them
    down and ring them out - then heave them in a trash can - soaked with
    water - do you think that this could still be a hazard?
    
    I guess I should just find myself a drying rack and follow the same
    procedure you all seem to agree on!
    
    Thanx .... d.

    I don't think rinsing them out would work, because you cannot displace
    the oil in the cloth fiber with water unless you used a washing machine
    on the hot cycle and I seriously believe that would ruin your machine
    8^).  It might keep the temp down and prevent the fire.  I did read
    that one way to store these rags is put them in a water filled
    container.  That sounded more like you immerse them to limit O2 thus
    preventing fire.
    
    Brian

>    container.  That sounded more like you immerse them to limit O2 thus
>    preventing fire.

As another noter noted, the problem arises when they evaporate to
dryness.

You immerse them to keep them from evaporating to dryness.

If it were my house on the line, I woudn't trust any amount of washing
with water.  We are not kidding around here.

    re: -1
    
    Yeah - I believe your warnings.  Time to handle these rags more
    cautiously.  Thanx for all your advise - I really appreciate it!
    
    
    d.

    I can attest to truthfulness of the spontaneous combustion
    danger of the Watco Danish oil through personal experience.
    I inadvertantly left one small Watco soaked rag on top of my table saw
    next to one of my new kitchen cabinets. The next evening, when I got
    home from work, my wife mentioned that she had smelled smoke from
    down cellar but could not fine the source.
    
    I went down and investigated and could not find any smoke either. In
    the process of looking around, I went to pick up what I thought was a
    rag on the table only to find that what looked like a rag was really 
    a pile of ash. It looked like a rag but was not. Similar to a coleman
    lamp mantel.
    
    This was one small rag left bunched up. It charred the cabinet but
    fortunately neither the rag or the cabinet burst into flame.
    
    Needless to say, I was puckered up for a week after that and still
    pucker when I think of what the outcome could have been.  
    
    I am extremely careful now. At a minimum, hang the rag so it is
    entirely exposed to air, preferably outside.
    
    John