[brenellic2000]

Don't use sump oil - its full of acids! The only reason people use sump oil of paraffin is because they are not prepared to do the job properly.... likewise so called CCA/Tanalised posts.

CCA salts are fixed - they don't leach out so are harmless to the immediate area. The tin based chemical (can't for the life of me remember its name!) deserves to be banned.

Many CCA/tanalised posts rot simply because they were never properly vac-vac treated in the first place - penny pinching cheapskates! We used the Bethell full-cell pressure impregnation at 250psi. (BS specs are by gallons/cu.ft not depth of penetration which can only be determined by destructive testing! Vac-Vac gives limited penetration.

Larch is naturally durable and will last up 20/25 years in ground contact without treatment! But many 'larch' posts are nothing more than common fir whitewoods while the new water-borne treatments are intentionally pretty useless to be 'safe'!!

Sue Butcher will likely know of the 'Turpentine' tree in Oz - it naturally repels white ants and sea-worms and was thus much used in marine work. In the 1890s some bright spark patented whale oil treatment for marine work as whales don't get attacked by sea-worms (honest)! His son likely recommended used paraffin and engine oil!

Drink turpentine and it will kill you; but you'll survive paraffin and paraffin wax!

Wood doesn't need protection from sun or water! Linseed oil will retard UV degradation while intelligent design prevents the trapped water which encourages insect and fungal attack! Back to square one!!!