On Tue, 15 Dec 2009 00:53:17 -0800 (PST), chris
wrote:

On 14 Dec, 23:16, Bruce wrote:
On Mon, 14 Dec 2009 23:06:19 -0000, "Cash"

wrote:

Dear Chris,

Not seen the reply by "Bruce" in this thread, nor will I if he posts via
google groups (all killfiled to ease the spam a bit).

You certainly wouldn't be able to recognise my reply from Chris's
response, because I said the exact opposite of what he is alleging.

For the record, I agree with you.

Chaps
For the record
Where I was agreeing with Bruce was when he said " You would be
removing the timber with the highest
concentration of preservative." He is quite right.
The facts are that Tanalith treatment was until about a decade ago
pretty good for protection because it contain CCA copper chrome and
arsenic. The heavy metal ions combined with the carboxyl groups
chemically and so the treatment was "fixed" as opposed to
"deposited". The end grain got penetrations of up to 50 mm. The side
grain varies with the porosity and permeablity of the wood - Scots
pine good Spruce bad/non existent. It could vary between say 0.5 mm to
perhaps 5mm (estimated figures). Thus, if you plane the side grain -
dependeding on the degree of initial treatment you remove some or all
of the protection. If the fence post is in the air and has been
treated with Sadolins or the like that ceases to be a problem as it
will not rot but if it is in ground contact and particularly at soil
level and 150mm above and below it will rot. Nitrogen salts get wicked
up the fence post and encourage decay at this point where the water
evaporates out (Ed Bains circa 1976)
It wont rot below as it is anaerobic and it wont rot above as it is
too dry. If you cut the end grain off and do not treat it the face of
the timber is no better protected than untreated timber and depending
on its natural durability and percentage sapwood it will rot if wet.
These are the facts
Chris


yawn