Bill, just curious, but why do you use raw linseed oil? Is it better
than boiled for protecting?
I've always used boiled linseed oil mixed 1:1 with turpentine & a dash
of Japan drier to coat tool handles. Makes a much better coating than
poly, IMO. I like the feel of it better. I was taught to use boiled
because it dried better. I've never used raw, though, so I don't
know. I think it would be pretty expensive to coat a fence in, at
least the way I soak it into the tool handles.
I've used old motor oil on stuff before & it's a really good protector.
Made a rabbit cage stand that sat in dirt out of cheap, SPF 1x3's &
coated it liberally with the stuff. It was about 10 or 12 years in
service before we moved & tossed it. Even where the boards dug into
the ground with a good seasoning of rabbit manure, were still in pretty
good condition. It's kind of messy though. Lean against the fence &
you'd stain clothes for quite a long time.
For a fence, to really protect it, you need to get the preservative in
where the rot sets in. That's the couple of inches either side of the
ground line & where the boards attach to the post. Those are the bug
infested, moisture retaining areas. I've never cared for face boards
or caps because they just promote rot, IMO.
If it were me, I'd probably go with something like Olympic or Cuprinol
stains. They're pretty good & come in lots of colors. They also dry
thoroughly, which motor oil doesn't. I think motor oil would be better
at protecting at the ground line, though.