How to Choose the Right Surface Finishing Product for the Job

There are many options on the market for completing grinding and surface finishing jobs. Abrasive tools are available in different sizes, grains and styles. So how do you know which choice is right for your application? Consider these key factors to help you make the decision:

WHICH PRODUCT CATEGORY?
The first step is to understand the three most common products used with a right-angle grinder for grinding and surface finishing:

• Grinding wheels provide the greatest durability and longest product life, but also offer the slowest cut and roughest finish.
• Flap discs offer a fast cut and moderate product life. Compared to using two different products for the job, flap discs grind and finish at the same time, helping save time in applications where surface finish is important. Flap discs also grind and finish at a consistent rate for the duration of disc life.
• Resin fiber discs have by far the shortest product life and are the least durable of the three options, but they also have the least expensive initial purchase price. These products typically cut very fast initially, but the cut rate and surface finish continually degrade since the grains wear and become dull from the first use.

To determine which product offers the most benefits for your application, ask the following questions:

Are There Surface Finish Requirements?
The desired surface finish impacts product choice. A flap disc is often preferred because it can blend and provide a consistent finish in one pass. Resin fiber discs will do the job of finishing, but can provide inconsistent appearance on large surface areas, which is not ideal for jobs with specific finish requirements. Grinding wheels are another option. However, since they leave a rough finish it is necessary to use a second tool for surface finishing, which increases labor time. Still, when surface appearance isn’t important, grinding wheels can offer cost savings and longer life compared to flap discs.

Is Damaging the Workpiece a Concern?
Flap discs or resin fiber discs are typically a better choice to avoid damaging the workpiece. Flap discs are generally more forgiving, so there is less chance of gouging the base material if you push too hard or slip. Resin fiber discs can also be forgiving, depending on the hardness of the backing pad being used. In comparison, grinding wheels are more rigid so they tend to have a greater potential for damaging the workpiece if you push too hard or the wheel slips. For this reason, it’s important to pull the wheel toward you rather than pushing it away on the first stroke. This reduces the chance of gouging, especially when using a new grinding wheel. By avoiding damaging the workpiece, you reduce the time and money spent on rework.

Do You Need to Increase Productivity?
The type of finishing tool you’re using impacts overall costs and labor time spent on the job. Choosing the right product can help improve productivity or throughput and reduce labor costs. When the application calls for a finer surface finish, flap discs deliver the greatest benefits for productivity and time savings since they grind and finish in one pass. In jobs where surface finish isn’t important, grinding wheels help improve productivity. They offer a better overall cut rate, longer product life and durability.

Is Initial Purchase Cost a Factor?
If initial purchase price is a key factor in your decision, resin fiber discs are the least expensive option. However, because these discs have a quick cut rate, they wear rapidly – and require more frequent replacement – compared to flap discs and grinding wheels. Resin fiber discs also require purchase of a backing pad. Since they have the shortest product life and a decline in cutting and finish appearance from the first use, resin fiber discs are best suited to smaller projects. When looking at purchase cost, be sure to also consider how much grinding and finishing you will do to ensure the best value. For example, one flap disc may provide the same life as 15 or 20 resin fiber discs, providing a greater return on investment.

CHOOSING THE RIGHT TOOL FOR THE BEST RESULTS
To reduce confusion when choosing among the many tools available for grinding and surface finishing jobs, consider the advantages and disadvantages of each product. Think about your priorities and what you need to accomplish: whether it’s product longevity, fastest cut or improved productivity. Knowing your goals and objectives helps you choose the tool best suited for the job, which can help you save time and money.