GrassFlap® Plastic vs. Steel Blocker Plate: Which One Is Right for You?

Choosing between the GrassFlap® plastic blocker plate and the GrassFlap steel blocker plate comes down to three things: 

• Ease of installationHow much assembly you're willing to do

• Forgiveness when accidently hung up

• The shape of your discharge opening

Both kits have the same price and do the core job of blocking grass and debris from discharging out the side of the mower deck. The kits operate the same way. 

Quick Answer

Plastic blocker plate:

• Ships as a blank requiring fitment at installation

• Is less expensive to replace if damaged.

• Provides some forgiveness when hung up.

Steel blocker plate 

• Ships pre-assembled, making installation easier

• Strong, less forgiving if hung up.

• Often comes pre-bent for rounded openings.

• More expensive to replace.

• More likely to transfer impact damage to the hinge.

Both kits cost the same up front.

Plastic vs. Steel Blocker Plate at a Glance

• Price: Both the Plastic and Steel blocker plates are priced the same.

• Ships as:

• Plastic: Unassembled (hinge, plate, deflector angle, hardware)

• Steel: Fully pre-assembled

• Install time:

• Plastic: Longer — trimming and drilling required

• Steel: Shorter — bolt on and go

• Rounded/tapered openings:

• Plastic: Can be cut and drilled using wood working tools, form using heat.Bendable by hand with a wrench and heat (torch or heat gun)

• Steel: Often pre-bent out of the box

• Impact behavior:

• Plastic: Plate absorbs the hit; hinge usually survives

• Steel: More rigid; can damage what it contacts. Also could damage hinge as well as blocker plate

• Replacement part cost:

• Plastic: Lower

• Steel: Higher

Frequently Asked Questions

Is the plastic blocker plate kit cheaper than the steel one?

No, the plastic and steel GrassFlap® kits are the same price at purchase. 

The cost difference shows up later if you ever need replacement parts: plastic replacements are less expensive than steel replacements.

What's included in the plastic blocker plate kit?

Plastic kits ship unassembled and comes with:

• Heavy-duty metal hinge

• UHMW plastic blocker plate 

• Separate plastic deflector angle

• Mounting hardware: 8 screws with matching T-nuts

What's included in the steel blocker plate kit?

• Heavy-duty metal hinge

• Steel blocker plate

• Deflector angle, built in on some units plastic on others. 

• Attaching hardware

• The steel kit ships fully assembled

Do I actually need the deflector angle, or can I skip it?

Install it: the deflector angle is a functional part, not an optional extra. 

The deflector angle creates a barrier above the discharge to shield the operator from clippings escaping out the top of the blocker. When initially opening the blocker plate a portion of the clippings go up rather than down until the blocker is open to enough of an angle that all the clippings get deflected down. Open to release built-up grass clippings, grass shoots either down or up. 

The deflector angle blocks the upward path so clippings don't fly back into the operators face.

How do I install the plastic blocker plate?

Trim the blocker plate to length, position the blocker to cover deck opening and drill mounting holes in blocker plate

Secure the blocker to the hinge plate with the deflector angle between the blocker and hinge plate.

Secure the blocker with the included 8 screws and T-nuts (the T-nuts sit on the outside). 

The kit arrives in separate pieces so plan on more hands-on assembly time than you would with the steel version.

How do I install the steel blocker plate?

Steel blocker plate come pre-assembled to the hinge plate. Certain steel blockers come with the deflector angle built in. Others may include plastic deflector. You will need to position the deflector if it is plastic. 

My mower has a rounded or tapered discharge opening. Will these fit?

Both will, but the effort differs. 

The plastic plate arrives as a blank, it can be modified to fit the discharge opening including cutting to length and forming it to match the curve of the deck. Heating the plastic with a propane torch or heat gun lets you set the bend. 

Most steel plates have with required bends already complete. Those that do require adding a bend are designed with a slot precut that makes it easy to bend as needed without special tools.

Which one holds up better if I hit an obstacle while mowing?

The plastic blocker plate is flexible and allows for some give. If it is bent it can typically be bent back with hand force.

The steel plate is more rigid: you can hammer a bent steel plate back into shape but it takes more effort. A hard-enough impact is more likely to bend the hinge along with the plate, necessitating a costlier repair.

Are replacement parts interchangeable or priced the same?

Plastic replacement parts cost less than steel replacement parts. The plastic blocker requires fitting at installation whereas the steel is bolt-on and go.

Which blocker plate should I choose for my mower?

Choose the plastic blocker plate if you: 

• Are hard on equipment

• Want lower-cost replacement parts

• Don't mind extra assembly time or hand-bending the plate for a tapered opening

Choose the steel blocker plate if:

• You want the fastest possible install with minimal assembly

• Your discharge opening matches one of the common pre-formed shapes

Can I switch from a plastic blocker plate to steel later?

Yes, GrassFlap® has a Plastic to Steel Conversion kit for owners who want to upgrade after starting with the plastic version.

Where can I find installation help for my specific mower?

GrassFlap® maintains manufacturer-specific instructional videos and installation guides. This includes, among others: 

• Scag

• Wright

• Toro

• John Deere

• Exmark

• Ferris

• Hustler

• Spartan
  

Use the GrassFlap® Lookup tool to match your mower's brand, deck size, and model year to the correct unit. 

If your make and model isn't listed, email support@grassflap.com with your mower brand, deck size, model year, and photos of your discharge opening, and our team will help you select the right fit. Connect with us on social media for more essential information for our chute blockers.