Using Power Tools 101

The power tools of today are not the same as the ones that were carefully placed on the pegboard near your grandfather's workbench- they are actually quite far from it. Modern technology has made amazing advances in the simplest of features, including automatic shut-off, enhanced guarding and more resilient materials just to name a few. But one trait has come to be worth its weight in gold within the power tool industry, and that's the owner's manual.

Today's manuals not only have better graphics showing its users what each part of the device should look like (and what to do when it doesn't), many individual manufacturers will have explicit directions and instructions for the safety and maintenance of each individual power tool. Of course, no instructions are completely fool proof, especially if the content of such manuals isn't completely understood by the user. This is why many manufacturers have implemented training seminars and classes for both companies and individuals on the proper procedures for optimum performance and safety. Local home improvement stores often hold such classes and seminars on a regular basis.

However, a bit of common sense and know-how never hurt anyone, so there are a few safety guidelines which should be followed by all users of power tools. For example, wearing the proper clothing is essential, and you should never wear loose clothing that could easily get caught in a power tool. Safety gear is crucial- hard hat, safety goggles and gloves, along with the proper footwear. Using the right tool, whether it be size or something else, for the job at hand, including the right type of extension cord (indoor, outdoor, proper length) if applicable. The work area should be clean, uncluttered and well lit. Keep all electric tools away from water and flammables. Do not use power tools with frayed or damaged cords. Damaged parts anywhere in a power tool, including saw blades and drill bits, can cause damage to the tool itself or the individual performing the task. Unplug all electric power tools when finished with or before changing to another tool.

As far as the maintenance aspect of such power tools, common sense is again of the highest importance. For example, making sure that the proper guards are placed on saw blades when not in use is both a safety and maintenance issue. Saw blades need to be sharp to deliver the best performance possible, but can also be incredibly dangerous, so taking the proper preventive measures will yield the best results in all aspects, not just project outcome. For more information on power tool basics, the U.S. government has many publications that can be of high value to consumers. The U.S. Consumer Product Safety Commission offers product recall information, and OSHA has a few such publishings regarding both general industry and personal use of power tools.

About the Author
Debbie Johnston recommends Makita power tools from BigScrewdriver.com.

Corrosion in Metals - Principles and Prevention

Corrosion is the tendency of metals to return to their natural condition, abandoning their current one, that is: the destruction or deterioration of a material because of chemical and/or electrochemical reactions.

A chemical reaction or dry environment reaction can occur by the contact with vapors or gases, without the presence of liquids. With frequency, the dry environment reaction is closely associated with high temperatures.

A electrochemical reaction or humid environment reaction, is present in liquid atmospheres, by sprayed or immersed means.

Corrosion processes tend to return materials back to a more thermodynamically stable state by their combination with substances in the environment, particularly with oxygen. It is from such a state that the materials were transformed through the metallurgic process of extraction and refinement, by the means of the supply of electric, chemical or heat work.

The most widely used metals for technology have a great affinity for oxygen and their corrosion process depends exclusively on the phenomenon denominated "oxidation". Some metals are more prone to oxidation than others.

For example: metals like gold or platinum hardly oxidize because of their low affinity with oxygen. They are known as noble metals. Other metals as iron oxidize easily due to their high affinity with oxygen.

Classification
The electrochemical nature of corrosion leads to diverse forms of assault. These are determined by the succession of a series of environmental, mechanical and geometrical factors. The identification of the form of corrosion is of vital importance for the diagnosis of the cause that determines the corrosive process, as well as the prevention, control, and protection of the element.

According to this, the corrosion classification goes as follows:
- Generalized corrosion
- Localized corrosion
- Selective corrosion

Generalized corrosion affects the whole surface of the metal and translates into a more or less rapid slimming of the metallic wall in contact with the electrolyte. Depending on the uniformity of the superficial attack, it can be differentiated into generalized uniform and generalized not uniform corrosions.

Localized corrosion affects a limited part of the metallic surface and causes cavity formation. These cavities, depending on their external diameter vs. depth relation, are named ulcers, craters, pittings, or criccas. The pitting or punctures, can sometimes be penetrating. The cricca or fissure can be intergranular or transgranular, depending if it follows the edge of the grain or through it.

Selective corrosion produces the preferential dissolution of a certain part of the metal that, for chemical or metallographic reasons, proves to be more easily attackable.
We can speak of cristalographic, intergranular or interdendritic corrosion, if the corroded material results in certain crystalline species in the grain borders or the immediately adjacent zone.

Another form of selective corrosion, the dealloying, happens when the preferential dissolution of one of two components of an alloy is verified, leaving an inconsistent and frothy residue of the other metal in the alloy.

Methods of control and prevention:
The general methods for corrosion control more widely accepted on the industry are: the use of special construction materials resistant to corrosion, the application of inert barriers as paint, the use of methods of cathodic or anodic protection, the adjustments on the electrolyte or corrosive medium's chemistry, the application of specific inhibitors to control corrosion, and the application of anticorrosive systems.

An anticorrosive system is made up of two components which form a set. This set works as a barrier that controls oxidation and prevents the attack of external factors.

The components of an anticorrosive system are:
- Firstly, the base or primer, whose function is to provide the system with the sufficient adherence to the substrate and to act as a cathodic corrosion inhibitor (because of its high proportion of zinc).

- The finishing, which consists of a film or layer that complements the system and provides a high resistance to the attack of the environment.

About the Author
The information for this article about metal corrosion was provided by Sika Mexico Plant. Sika is a world renowned manufacturer of specialty chemicals for the construction and manufacturing industries. For more info visit http://www.sika.com.mx