In this article, we'll go over flap disc basics and flap disc features including backing and density. We'll also compare flap discs with grinding wheels and fiber discs, so you can better identify when a flap disc best suits your metalworking application.
What is a flap disc?
Flap discs were developed as an alternative to resin bonded grinding wheels and fiber discs. Due to advances in the welding processes over the years (i.e. smaller welds from TIG and MIG wire), a flap disc requires less weld to be removed than other processes (including stick welding). With a flap disc, the operator can still remove the weld quickly and blend/finish it in minimal steps.
- Flap discs are constructed by layering multiple coated abrasive flaps so as they wear away, new, sharp grain is exposed.
- Flap discs increase productivity and reduce total overall costs by grinding, blending & finishing in one simple step.
- Flap discs are quieter and smoother running than traditional abrasive wheels.
backing Shape
There are two basic shapes of flap discs:
Type 29 (Conical ShapE):
- Built-in, higher angle for increased contact area and more aggressive stock removal.
- Best for use on contoured surfaces and edge work.
- Minimizes workpiece gouging.
- 15°-25° working angle.
Type 27 (Flat ShapE):
- Best for use on miter joints, corners and edges.
- Best choice for finishing intricate and ornate surfaces.
- Ideal for smooth finishing.
- 0°-15° working angle.
BACKING TYPE
The backing type, or backing material, of a flap disc supports the flap disc’s abrasive material and acts as the surface the abrasive flaps are adhered to.
- Polyester: Able to withstand extremely high pressure without degrading the flap. For extreme stock removal and edge grinding.
- Cotton: Used where maximum conformability and soft feel is the goal. Must be used under lighter pressure to maximize performance and life.
- Polyester/Cotton blend: The best of both worlds. Can withstand high pressure while still maintaining good stock removal and finishing. Often used as the starting point for flap disc operations for first time users.
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United Abrasives Fiberglass Backing: Custom engineered fiberglass backing plates provide outstanding strength, durability, and safety. United Abrasives fiberglass backing is composed of more fiberglass than competitors, making United Abrasives flap discs among the safest on the market.
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United Abrasives Plastic Backing: Non-scratching, high strength backing is resistant to extreme temperatures, common chemicals, and solvents. United Abrasives Plastic backings are available with your choice of:
- Soft ABS Plastic Backing: designed to be trimmed to expose more abrasives material.
- Hard Plastic Backing: designed for high strength and rigidity promoting ease of use and long-life.
Density
Flap Disc Density refers to the thickness of the abrasive material on the flap disc.
Regular (Standard) Density Flap Discs: regular density flap discs are excellent choices for aggressive stock removal and demanding industrial applications.
High Density Flap Discs: high density flap discs contain approximately 40% more material than regular (standard) density flap discs. High density flap discs are best suited for uneven or curved surfaces, or for blending and finishing rather than heavy stock removal.
the United Abrasives FLap Disc difference
Adhesive System: Specially formulated adhesive system, designed to effectively secure the abrasive flaps to the backing, maximizes abrasive performance and safety.
Coated Material: United Abrasives has its own unique coated material that has been specifically designed for flap discs.
Flap Design: United Abrasives utilizes a larger quantity of flaps per wheel and larger-sized flaps than competitors to yield great performance and product life.
Abrasive Grains: The grains within any abrasive are what actually do the cutting or grinding. The grain used in a flap disc determines that particular disc’s cut, life and cost ratio. You’ll find two different types in United Abrasive flap discs, which include:
- Ceramic: opt for a ceramic flap disc when grinding on steel, stainless steel or aluminum. Ceramics tend to grind cooler, minimizing discoloration while maximizing product life
- Zirconium: zirconium flap discs are used for general steel grinding, stock removal and finishing. Zirconium flap discs offer an economical choice when cost is the driving factor.
FLap Disc comparison
Ultimately, the right choice of abrasive solution depends on your application, material and preference. We've compared flap discs against grinding wheels and fiber discs to help you quickly identify when to choose a flap disc vs an alternative solution.
FLap DiscS Vs. Grinding Wheels
- Flap discs provide faster stock removal and smoother finish.
- Flap discs offer quieter operation and reduced vibration, minimizing operator fatigue.
- Flap discs are cooler cutting, and reduce the loading and glazing that is common to grinding wheel usage.
- Flap discs are easier to use than grinding wheels, reducing risk of gouging and rework.
FLap DiscS Vs. Fiber discs
- Flap discs offer up to 20 times longer life than a fiber discs.
- No backing pad is needed with flap discs.
- Flap discs allow easier storage – no curling!
- Flap discs provide a more consistent finish.
Need More help selecting the right Flap Disc?
Download the United Abrasive Technical Info & Safety Guide for comprehensive selection charts and technical data on their wide offering of flap discs, cutting wheels, grinding wheels, and more.
