FAQ: Flap Discs

Can I use a ceramic discs on a right angle grinder that is lower wattage?

You are able to use flap discs on a lower watt tool, but keep in mind that these products are designed for tools with more power.

Can I use flap discs for a similar application related to a resin fiber disc?

You can use a flap disc, but You need to choose a coarser grit because of the multiple layers and shorter life in comparison to the single layer and supporting backing plate of a resin fiber disc.

What are the most common arbor sizes?

The most common sizes are 7/8″ and 5/8-11″.

What are the two types of flap discs?

The two types of discs are Type 27 and type 29.

Which type has a flat face?

Type 27 is a flat face disc.

Which type has an angle face?

Type 29 is an angled face disc.

What size is the arbor for a 4” disc?

The arbor size for a 4″ disc is 5/8″.

What are the dimensions listed for a flap disc?

The dimensions are listed as follows: diameter x arbor hole size.

What backings are available for a flap disc?

Available flap disc backings are fiberglass, plastic/nylon, and aluminum.

Why would you use an aluminum backed flap disc?

Aluminum backed flap discs are more rigid, which makes them suited for heavier grinding.

What does HD stand for on a flap disc?

HD stands for high density, which means it has more flaps than a standard flap disc.

Whats the advantage of a high density flap disc?

High density flap discs are less aggressive, but may last longer due to the extra flaps.

What are most common backing plates for flap discs?

The most common flap disc backing is fiberglass.

What is the advantage of the 5/8-11″ on a flap disc?

The advantage is that a lock nut is not needed to secure the flap disc to the grinder, therefore making it faster to change.

What are the common grain for flap discs?

The common flap disc grains are aluminum oxide, zirconia, and ceramic.

What flap disc grain should I use on stainless steel?

Ceramic is the best grain suited for stainless steel.

What kind of grain is on a blue flap disc?

If the flap disc is blue, it’s most likely a zirconia grain.

What color is a zirconia flap disc?

A zirconia flap disc is most commonly a blue color.

Why would someone use a plastic backing on a flap disc?

A plastic/nylon backed flapped disc is more cost effective, and can be trimmed.

What are common applications for flap discs?

Flap discs can be used for weld removal, spatter clean-up, and beveling edges.

What is the advantage of a flap disc over resin fiber disc?

A flap disc can leave a finer finish and last longer.

What is a flap disc?

A flap disc is a layer of abrasive flaps that are designed to expose the new grain on each single flap as the others wear away.

Why would someone use a Type 29 instead of Type 27 flap disc?

A type 29 is designed to remove material faster, especially if the grinder is held at an angle to have more cutting points touching the work piece.

Why would someone use a type 27 flap disc?

A type 27 flap disc is used for blending and smoothing on flat surfaces.

What is the arbor size of a 4″ flap disc?

A 4″ flap disc arbor size is usually 5/8″ or 3/8-24″.

What type of grain on the flap disc should be used on mild steel?

Zirconia or ceramic grains are proven optimal on mild steel.

What is a flapper wheel?

A flap disc can often be called a flapper wheel.

What are the available sizes for flap discs?

Flap disc sizes are available in 4″, 4-1/2″, 5″, 6″, and 7″.

What is the arbor size for a 7″ flap disc?

A 7″ flap disc arbor size is usually 7/8″ or 5/8-11″.

What flap disc grain is a bright red color?

A bright red grain is typically ceramic.

What flap disc grain is a dull red color?

A dull red grain is typically aluminum oxide.

What is a tiger paw?

A flap disc is also called a tiger paw.

What type of grain should be used on aluminum?

A zirconia or aluminum oxide flap disc is typically used on aluminum.

What does the size of a flap disc mean?

The size of the flap disc refers to the diameter of the disc.

What metals is a ceramic flap disc used on?

The recommended metals are stainless steel or mild steel.

What information do I need to ask about a flap disc?

You need the diameter, arbor size, what grit, what type (27 or 29), and the type of grain (aluminum oxide, zirconia, or ceramic).

What are the measurements of a flap disc?

Flap disc measurements are diameter first, and then the arbor size.

What tool is a flap disc used on?

The recommended tool for a flap disc is a right angle grinder.

What flap disc size should I use?

The size should be determined by the size of the grinder. Make sure the grinder does not exceed the max RPM on the disc.