paulw
New member
- Joined
- Dec 21, 2001
- Messages
- 18
- Location
- Mooresville, NC area
- Tractor
- NH TN65 FEL+4x4 and IH 364 (does any body have one of these other than me)
Both pentachlorophenol and creosote are restricted use pesticides and can’t be easily obtained. In pressure treatment, normally creosote is used as a 50% solution in petroleum oil or without dilution while a 5% penta solution in oil is used. Copper naphthenate is still available used at a dilution in oil (diesel or #2) to 2% copper for brush or dip application. Copper naphthenate has a characteristic odor that persists.
One treatment method that was used years ago was the hot and cold bath technique. The poles are immersed in a hot preservative solution that expands the air in the poles. They are then placed in the cold preservative solution. The cooling cause the air to contract creating a partial vacuum that draws in solution as the pressure equalizes. Another technique is double diffusion that works better with unseasoned wood. Soak the poles in a water solution of sodium fluoride followed by soaking in copper sulfate solution. The fluoride and copper ions react forming the water insoluble copper fluoride compound in the wood. Each soak period must be long enough to allow the water-soluble salts to diffuse into the wood. These non-pressure methods will provide fair decay and termite protection but not equivalent to pressure treated wood treated to specification.
For fence posts dip treatment would work OK, treat from the bottom to couple feet above the expected ground line. Then after the posts are in soak the tops with preservative. However, for structural applications you would be much better off settling the posts on concrete piers above the ground line also soaking the concrete exposed end with preservative. Fence posts can be replaced relatively easily and a few failures will be of little consequence compared with structural members.
The USDA Forest Products Laboratory has a publication on wood preservation. This mainly covers industrial pressure treatment chemicals and processes but also discusses non-pressure methods and treatability of various wood species. The link is http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch14.pdf
One treatment method that was used years ago was the hot and cold bath technique. The poles are immersed in a hot preservative solution that expands the air in the poles. They are then placed in the cold preservative solution. The cooling cause the air to contract creating a partial vacuum that draws in solution as the pressure equalizes. Another technique is double diffusion that works better with unseasoned wood. Soak the poles in a water solution of sodium fluoride followed by soaking in copper sulfate solution. The fluoride and copper ions react forming the water insoluble copper fluoride compound in the wood. Each soak period must be long enough to allow the water-soluble salts to diffuse into the wood. These non-pressure methods will provide fair decay and termite protection but not equivalent to pressure treated wood treated to specification.
For fence posts dip treatment would work OK, treat from the bottom to couple feet above the expected ground line. Then after the posts are in soak the tops with preservative. However, for structural applications you would be much better off settling the posts on concrete piers above the ground line also soaking the concrete exposed end with preservative. Fence posts can be replaced relatively easily and a few failures will be of little consequence compared with structural members.
The USDA Forest Products Laboratory has a publication on wood preservation. This mainly covers industrial pressure treatment chemicals and processes but also discusses non-pressure methods and treatability of various wood species. The link is http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch14.pdf
