USr OF PERISHABLE WOODS FOE FENCE POSTS 201 



The most effective method of preserving fence posts is 

 without doubt by destroying the food value, so that the fungus 

 cannot live in ■ it. The substances most commonly used for 

 this purpose are poisonous salts, like copper sulphate, corrosive 

 sublimate and zinc chloride, and oils such as crude oil and 

 creosote. The use of salts for preserving fence posts is of 

 value only in regions of scanty rainfall. In a moist climate 

 salts are easily leached out of the wood. Creosote, which is 

 a product of the distillation of coal tar, is the most important 

 wood preservative. It not only poisons the wood so that fungi 

 cannot live in it, but, being an oil, it tends to exclude moisture. 

 Most of the patented wood preservatives on the market have 

 creosote as their base. It can be obtained through hardware 

 dealers. 



METHODS OF TREATING FENCE POSTS WITH CREOSOTE 



There are three methods of treating fence posts with creo- 

 sote, the brush method, the dipping method and the open tank 

 method. 



The Brush Method of Treating Fence Posts. — The brush 

 method consists in painting the posts with creosote. The 

 posts are thoroughly dried and seasoned so that the creosote, 

 which is applied hot, will be absorbed by the wood. The 

 creosote is painted on the posts with an ordinary paint brush, 

 and at least two coats should be given each coat being allowed 

 to sink into the wood befoi-e another is applied. While the 

 brush method will prolong the life of posts somewhat it is 

 not an effective method because the creosote does not sink 

 deeply into the wood and is easily leached out, and it is im- 

 possible to get the creosote into all cracks and season checks 

 and defects, through each of which the fungus can gain en- 

 trance to the wood. The life of all timbers used in contact 

 with the ground or where subject to damp conditions can be 

 lengthened many years by this method. 



