Understanding surface preparation.
As the applications are diverse, so too are the products and equipment: shot-blasting equipment, acids and chemicals, surface planers (scarifiers), and surface grinders. Chemicals and acids are often used for stripping floors, but as concerns about disposal grow, surface preparation contractors are beginning to search for other means. This search has lead to increased demand for planers and grinders.
Planers vs. Grinders
If I had to use one word to describe a surface planer, I would say it is a "destroyer," since it destroys surfaces. It uses flails and an enormous amount of energy to impact a surface.
A surface grinder on the other hand is much more relaxed and can be defined as a "restorer." There is less impact energy, and the effects are realized more slowly.
Often a planer and grinder will be used on the same application because the machines complement one another. The planer will perform the tough applications (remove coatings that need the impact energy of flails), and the grinder will smooth the surface before re-coating.
When determining the proper surface preparation equipment five factors must be considered.
* What type of material is being removed? There are thousands of coatings or epoxies on the market that are being applied, and obviously, people do not always remember what material was used. Knowing the type of material is critical in determining the right process for effective removal of the coating.
* How thick is the material? Generally speaking, a thick coat is easier to remove because it will have a weaker mechanical bond to the cap surface.
* What type of base surface is it? It is essential to determine whether the base surface is concrete or asphalt to determine the most effective process.
* What is the condition of the base surface? The base surface may be relatively new and smooth, and it will be fairly easy to remove a coating. Conversely, the surface may be cracked, broken, or eroded, making it difficult to remove material from the hills and valleys in the concrete.
* What are the environmental factors of the application? If removing material inside a building, engine exhaust and chemical fumes may be a concern. In that case, an electric-powered machine may be preferred. When purchasing an electric machine, power requirements and additional equipment requirements must be considered.
The answers to these questions will enable contractors to make better decisions regarding surface preparation equipment. However, the trouble with surface preparation is that we are dealing with a subjective process. I always tell people it is not like pumping water because water is water wherever you go in this world. With surface preparation there are so many different coatings that you never really know what you are getting into until you start the job - but that is also what makes it exciting and interesting.
Obviously, for removing traffic line material and grinding down a misaligned sidewalk you would always use a surface planer. However, there are few cases where the solutions are that clear. We encourage customers to call the manufacturer for advice.
Choosing the right flail configuration is frequently an overwhelming task. The answer can be quite simple. For the majority of planer applications, the pentagonal shaped tungsten-carbide tip flail is the most practical. Unfortunately, this flail is also the most expensive. But, it offers an extended surface life and is much more aggressive than other flail configurations.
When purchasing surface preparation equipment, there are several key factors to consider.
What am I getting for my money? Obviously, features and benefits are crucial when buying equipment. A well designed machine will be very productive - something extremely important to contractors. But there is something else customers should receive with the equipment - a link to the manufacturer. A sound manufacturing company will stand behind its product and provide unparalleled support and service for its equipment.
Most manufacturers will encourage a dialogue with customers to assist problem solving. Supplying the product and supporting it is paramount for any manufacturer. It is not uncommon for me to get a call at home on a Saturday from someone trying to figure out the best equipment to use for a particular application. I think most manufacturers would encourage those calls. We would rather be contacted for advice than have a customer use a product incorrectly or use the wrong flail configuration and not be satisfied. Anybody can build surface preparation equipment. Providing background and support for people in the field is what sets a manufacturer apart.
What is the utility value of the machine? The number of applications a piece of equipment is suited for will affect its return on investment. If a machine just sits in a shed gathering dust because it can only be used for one application, it is not making any money. For years, this was the case with a surface grinder, but that has changed with the introduction of attachments such as the SCRAPE-R-TECH[R]. Many companies make similar attachments, enabling a surface grinder to do more then grind down concrete. The attachment utilizes a series of tungsten carbide inserts to enable a grinder to remove coatings and prepare surfaces for re-coating. By designing these attachments, manufacturers increase a surface grinder's utility value.
The size of the machine also impacts utility. Generally the heavier the machine, the more productive it will be, due to a reduction in recoil energy. The more a machine bounces around, the less productive it is because recoil energy is wasted energy.
Mr. Von Ruden is the president of General Equipment Company, Owatonna, Minnesota.