Lawn mower blades -- How to extend their life

Lawn mower blades get mechanical abuse a lot during the normal course of operations. Grass is actually very abrasive. After getting yourself a very expensive lawn mower and spending a lot of money, what is the point of still using old style blades that have no additional features. It is now time to start thinking of innovative methods to extend the life of your lawn mower blades.

This life extension can be done using a process called thermal spray. The procedural steps are as follows. The first step in thermal spraying your lawn mower blades is to clean it thoroughly with a solvent such as acetone. Then mask the body of the blade where no cutting takes place using a thermal spray masking tape. These are usually a high temperature tape designed specially for thermal spray coating operations. This will expose the surface of the blade just a little bit beyond the cutting edges. The third operation is abrasive grit blasting to develop a roughened mechanical profile on the blade surface. Note that thermal spray coatings are bonded to the surface by mechanical means and hence a well cleaned surface with an excellent profile goes a long way in developing a good mechanical bond.

Now a bond coat with a material such as nickel-aluminum or nickel-chrome-aluminum is preferred. Such a bond coat will improve and enhance the mechanical and metallurgical adhesion of the subsequent top coat; just like you would use primer before a standard coat of paint. For the top coat, use tungsten-carbide-cobalt as the preferred choice and deposit using the plasma thermal spray process. Apply a reasonable thickness. The next step is to remove all masking. The following step is to grind the applied coating properly to develop the sharpness of the blade profile.

Now you have a high quality tungsten-carbide coated lawn mower blade. It is preferable that you use the services of a reputable thermal spray shop, because the parameters used in depositing the coating are important and they can be the difference between getting good wear resistance and not so good results. Again, as always, check with the original equipment manufacturer if your process is acceptable or not, because they may have clauses that relate to warranties and the like. They may even advice on the safety aspects involved.

The more you learn more about thermal spray coatings the more you might find other applications in your day to day life.