dpb wrote:

Pete C. wrote:
dpb wrote:
Doug Miller wrote:
In article , dpb wrote:

The solvent problem I think can be discounted as being too far removed
in time
Maybe so, but it's also possible that the OP's memory of what was done when is
imperfect, and that the solvent use was actually much more recent; that's more
likely IMO than an internal heat source that doesn't cause *any* apparent
damage to the OSB, *or*, apparently, to the paint on the inside of the house.
He "forgot" this within the last two weeks?

I personally couldn't tell there was no apparent damage or not to the
OSB from the last pictures because all was shown was a fairly distant
view of the sheathing through the hole in the Tyvek so there was no way
to judge any coloration difference of that localized area vis a vis the
removed area.

Other than the possibility of the postulated arcing being almost
directly in contact w/ the inside wall of the sheathing, I agree it's
difficult to imagine there being such visible exterior damage w/o there
being any indication on the inner wall except for the fact that the
location is below the cabinet top and therefore, there presumably is a
back to the lower cabinets which is another layer of
protection/insulation/coverup.

Overall, I'm still convinced from the picture it was external, it was a
heat source and most likely somebody pushed the grill over there at some
point; perhaps while OP was out of town or making a "honey-dew" run to
the market for the forgotten items from the market or some such...

and frankly the damage pattern just doesn't have the shape for
that to have been the cause unless it were a misdirected spray gun blast
and the reported application was rubbing w/ a rag instead...
No, he said he sprayed the stain:
...

Yes, but he said he wiped the solvent on manually to clean up the
overspray (and, no, I'm _not_ searching back through the thread to find
it... )...

Only when and if OP actually finishes an investigation and reports back
will anything else possibly be learned...
True enough.
But, being usenet, it certainly can't/won't slow down conjucture,
can/will it?

--

I don't believe arcing itself generated the heat, I believe arcing
caused a fire in the wall cavity that generated the heat before it self
extinguished. I'd put 80% odds on the OP finding significant fire damage
in the wall cavity when he opens it up.

I'll take that bet -- I think it's external by about 90%...

--

Guess well have to await the OPs next response and photos to see who
wins.

Pete C.