On the topic of funky wood coats, did you consider linseed oil/turps
mix?

Brian W

On 7 Oct 2004 00:19:35 -0700, wrote:

And in tribute to Dave Carnell, if he still walks the earth, this is
not marine but is the biggest risk I've tried so far:

My house is sided in 1" roughsawn vertical shiplapped pine boards from
my woodlot. Don't ask why I did this 16 years ago, because today I
could sell the beautiful old-growth air-dried pumpkin pine which looks
rather funky on my house on its best day, buy expensive cedar
clapboards plus paint them, and have enough cash left for a long trip
to an enchanting place. It was originally bleached/brush-cleaned
after erection & "sealed" (not) with Clear Solution 3000. FWIW this
was gunned with air & not backbrushed.

Naturally no pigmentless coating protects for long, and 3-4 years
later it was gray-streaking & ready for another bleach/clean/respray
routine.

But it didn't get started until last week, 12 years too late. :-) Of
course by then a lot of it was totally gray, and bleaching/cleaning
also meant removal of a lot of wasted cellulose (strongly adhering
residue that must be brushed or pressure-washed off, or both). Having
avoided this onerous, weather-dependent and not-free task for 3x as
long as prudent to defer, I considered some way to make the next
cleaning & coating last longer.

I didn't want any coating that would color the wood beyond the slight
ambering of the 3000, because it is full of pinks & oranges & nutty
browns, and I wasn't about to Cetol or Watco the whole house to get
high durability or longer life.

I reasoned that after bleaching, cleaning & drying, only a single
spray-to-runoff of EG with a garden sprayer might penetrate enough of
the wood - say, 1/8" or more - to make the Clear Solution job last a
lot longer. I also felt that this method on vertical siding would end
up wetting the lower ends more - which mildew & discolor first &
fastest from backsplash etc. The ph of rain here is about 4.0, which
doesn't help things either along with the acid red oak leaves, pine
needles, etc.

So while looking at my now-beautiful clean, dry pine, I poured cheapo
WalMart green antifreeze into the sprayer, prayed it wouldn't make any
green hue or destroy my little handbuilt home, knew it would be
irreversible, donned a face shield, took it to the steel roof & went
for it on the upper half-storey.

The first thing I learned, is that antifreeze turns pitched galvanized
steel into something more slick than ice. :-) This dictated some
careful planning & antics related to the order of spraying. I am
chicken enough on a low-pitched roof on land (I can climb kingposts &
stacks all day at sea), without this added terror. I wouldn't want to
be depending on gelcoat for traction while spraying EG.

The second lesson, it that it takes 2 - 3x as much EG to wet wood this
way than a sprayed coating takes to cover well. So at $7 a gallon, it
costs as much as a conventional coating to apply thinly like this.

After spraying, the wood appeared darker than it had when simply still
wet from cleaning, and the color balance was very different. It
looked horrible and I was very worried.

After 3-4 days of good drying weather, it has come back to the same
tones it had right after cleaning. There is no hint of any greenness
whatsoever. I was *very* relieved & inspired.

But the third thing I learned, is that hygroscopic EG (with a bit of
DEG & other minor junk thrown into auto antifreeze) takes *forever* to
dry in open air at midrange RH at 60 - 70 F. A poplar pallet I had
lightly sprayed had dried quickly in 80F weather.

It is still wet, and it is unclear whether it will be coatable before
encroaching late fall weather precludes it. Even directing fans at it
during the day to greatly increse outdoor airflow aren't doing much to
speed things up. I am concerned that whenever atmospheric moisture is
high, it may hygroscopically rewet itself - or never dry enough to
accept the 3000 via airless.

I am concerned about getting it dry & coated before the EG is leached
back out of the wood by weather.

But it looks beautiful.

So far. :-)

It will take me at least 3-4 years after I'm able to recoat it, to
begin meaningfully knowing how it has worked.

But at high risk I've demonstrated that it will not noticeably change
the appearance of clean wood, possibly excepting *very* light wood.
Included in this treatment are a sheltered outdoor overhead of planed
(5/4) pine, and exposed 6x8 hemlock timbers. The pallet referred to
is very light wood and shows no greening, though it was also only
lightly sprayed to runoff.

The lower 4' of my house is a curved double stone wall of the usual
3:1 porous mortar mix, with wide joints & carefully-selected stones of
many colors. Getting them soaked with antifreeze runoff had no visual
effect whatsoever. Ditto for other granite & brick around the place.
Neither do I have any dead grass from EG runoff.