January 15, 2010
What Different Types of Wood Preservatives Are There?
When it comes to the many different kinds of construction materials which are present in your home or place of business, perhaps the most difficult to care for over the course of time is wood. Coincidentally, wood also happens to be one of the most popular and fashionable construction materials to be found in homes: the pattern of the wood grain and the rich tones which many of the more prized varieties of wood exhibit are highly appreciated in the fields of architecture and home design, appealing to our noblest sense of aesthetics. It is precisely these exceptional qualities which make it so important and which give us such a tremendous desire to care for and preserve wooden structures and surfaces throughout the home from the many threats that inevitably present themselves. These include but are not limited to exposure to moisture, direct sunlight, and infestation by various insects among which the woodworm (which is not one species but rather a handful of different kinds of beetles in the larval stage of development).
Fortunately for home owners, modern chemists have identified many kinds of natural wood preservatives and helped develop many additional synthetic wood treatments which, when used in the proper combination and sequence, can work wonders on wooden installations small and large, whether the item at hand is a piece of furniture or is part of the structure of the home itself. So, let’s take a look at a few examples of effective wood preservatives available on the market today:
The lumber or timber industry has come a long way in the kinds of chemicals which it uses to preserve wood: in the past it was common for highly toxic chemicals such as arsenic or chromium to be used for not only industrial but even for residential wood supplies. While some risky chemicals continue to be used for industrial installations, residential supplies are now treated with safer wood preservatives pursuant to stricter human safety and environmental protection legislation.
All the same, wood preservatives in general fall under the category of pesticides, and as a result it is important that treated wood be handled with certain precautions. The treatment of wood with such preservatives generally occurs through a pressurized or vacuum process. It is of course a much different story when talking about at-home applications of wood preservatives, which is the topic of interest here.
There are three principal varieties of wood preservatives available at the moment, and they are: water-borne preservatives, oil-borne preservatives, and light organic solvent preservatives. Each has distinct advantages and drawbacks, and each should be used in specific (though occasionally overlapping) circumstances.
Water-borne preservatives are usually among the cheapest options available to consumers and this is perhaps their greatest virtue; conversely, their greatest drawback is the fact that, due to the presence of water in such preservatives, their application can and often will lead to swelling and/or warping of the wood to be treated, especially if it is already porous. Many water-borne preservatives use copper or a copper-based compound as the main ingredient, as is the case with chromated copper arsenate, alkaline copper quaternary, and copper azole (three of the most widely used water-borne preservatives). Additional copper compounds such as copper HDO, copper citrate, and acid copper chromate are frequently employed.
Apart from copper compounds, this category includes various other sodium silicate- and potassium silicate-based preservatives (in certain cases referred to as “waterglass” preservatives), which in the latter case are largely extracted from natural products such as plants.
Moving on to the oil-borne preservatives category, the most common varieties here include creosote and pentachlorophenol, neither of which are very common for consumer products though they may be included in certain structural wooden components of a home.
Then, the category of light organic solvent preservatives is dominated by paraffin-based solvents (such as white spirit), which despite their lack of heavy-metals as compared to other categories have been jeopardized by the passage of recent regulations on volatile organic compounds.
Finally, there are new wood preservative technologies such as wood acetylation and heat treatments. A notable trend in the development of modern wood preservatives points in the direction of more environmentally friendly compounds that require simpler handling by consumers, making it easier for the average person to put such products to use.
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