When it comes to mixing mortar, screed, terrazzo, self-leveling compounds, render, or concrete-based materials, a forced action mixer delivers significantly better mixing quality than a conventional drum mixer. By forcing the material through multiple mixing blades rather than relying on gravity, forced action mixers provide faster, more consistent, and lump-free results.
Forestwest offers three popular commercial-grade forced action mixers:
- BM678 – 120L Maintenance-Free Forced Action Mixer
- BM680 – 160L High-Capacity Maintenance-Free Forced Action Mixer
- BM679C – 120L Portable Forced Action Mixer
While all three machines are designed for professional construction applications, each model targets a different type of user and workload.
Specification Comparison
|
Specification |
BM678 |
BM680 |
BM679C |
|
Drum Capacity |
120L |
160L |
120L |
|
Batch Output |
90L |
120L |
90L |
|
Motor Power |
2000W |
2500W |
2200W |
|
Mixing System |
3-arm mixing blades |
3-arm mixing blades |
4-arm mixing blades |
|
Mixing Arm Removal |
Mixing arm can be lifted out directly for easier cleaning and inspection |
Mixing arm can be lifted out directly for easier cleaning and inspection |
Mixing arm is secured by a nut, which needs to be released before removal |
|
Gearbox Type |
Higher-grade Helical Type-R Reducer (maintenance-free) |
Higher-grade Helical Type-R Reducer (maintenance-free) |
Traditional Cycloidal Reducer |
|
Paddle Speed |
30 RPM |
30 RPM |
30 RPM |
|
Weight |
124kg |
133kg |
136kg |
|
Maintenance Requirement |
Maintenance-free gearbox; general cleaning and inspection only |
Maintenance-free gearbox; general cleaning and inspection only |
Periodic gearbox grease replacement required; lithium-based grease recommended |
|
Commercial Duty Rating |
Heavy Duty |
Heavy Duty |
Medium-Heavy Duty |
The BM678 and BM680 use Forestwest's higher-grade Helical Type-R reducer gearbox, a maintenance-free design with permanently lubricated bearings. This R-type gearbox requires no routine gearbox maintenance or grease replacement under normal use, improving long-term reliability and reducing downtime. The BM679C adopts a traditional cycloidal reducer system combined with a four-blade mixing arrangement. While highly effective, the BM679C gearbox requires periodic grease replacement, with lithium-based grease recommended.
BM678 – The Best All-Round Commercial Mixer
The BM678 is arguably the most balanced machine in the range.
Its 120L drum capacity and 90L batch output make it ideal for:
- Screed installation
- Mortar mixing
- Terrazzo work
- Residential construction
- Small commercial projects
Key Advantages
Maintenance-Free Gearbox
The BM678 uses a higher-grade Helical Type-R reducer gearbox designed for continuous commercial use. Its permanently lubricated gearbox design means no routine gearbox maintenance or grease replacement is required under normal use, giving it a clear advantage over traditional gearbox systems.
Excellent Mixing Consistency
The three-arm paddle system continuously moves material from the outer edge toward the center of the pan, producing a highly homogeneous mix.
Easy Transportation
At 124kg, the BM678 is lighter than the larger BM680 and can be loaded onto a ute or trailer by a single operator using ramps.
Best For
Contractors who require a reliable, low-maintenance machine for daily use without needing maximum production volume.
BM680 – Maximum Productivity for Professional Contractors
The BM680 is essentially the larger and more powerful version of the BM678.
With a 160L drum and 120L batch output, it offers approximately 33% more production capacity per batch.
Key Advantages
Larger Batch Capacity
The increased output means:
- Fewer mixing cycles
- Reduced labour costs
- Higher daily productivity
This is particularly important for:
- Large screed installations
- Commercial flooring projects
- Terrazzo production
- Concrete repair works
More Powerful Motor
The 2500W motor provides additional torque when mixing heavier materials or operating with near-full loads.
Same Maintenance-Free Design
Like the BM678, the BM680 uses the same higher-grade maintenance-free R-type reducer system:
- Permanently lubricated bearings
- Higher-grade Helical Type-R reducer gearbox
- No routine gearbox maintenance or grease replacement required
- Commercial-duty steel construction
Best For
Professional contractors who run continuous daily operations and require the highest productivity from a portable mixer.
BM679C – The Economical Heavy-Duty Alternative
The BM679C follows a different design philosophy.
Rather than using a three-arm paddle system, it employs four mixing blades positioned at different heights throughout the drum.
Key Advantages
Aggressive Mixing Action
The multi-level blade arrangement creates excellent vertical material movement throughout the mix.
This makes the BM679C particularly effective for:
- Mortar
- Render
- Cement-based compounds
- Dry and semi-dry screed
Traditional Cycloidal Reducer
The BM679C uses a traditional cycloidal reducer. It delivers strong torque and shock-load resistance, but unlike the BM678 and BM680 R-type reducers, it is not maintenance-free.
- High torque output
- Compact design
- Strong shock-load resistance
Commercial Construction
The heavy-duty steel drum and 2200W drive system provide plenty of power for demanding applications.
Considerations
Compared with the BM678 and BM680, the BM679C requires more routine gearbox and drive-system attention, including:
- Gearbox grease condition and periodic grease replacement
- Drive components
- Blade wear
For BM679C gearbox servicing, lithium-based grease is recommended when replacing the grease. For users prioritizing simplicity and minimal maintenance, the BM678 and BM680 maintenance-free R-type gearbox models offer a clear advantage.
Best For
Users seeking a cost-effective commercial mixer with strong mixing performance and proven gearbox technology.
Which Mixer Should You Choose?
Choose BM678 If:
- You want the best balance between price and performance.
- You need a maintenance-free gearbox with no routine grease replacement.
- Your projects are primarily residential or small commercial.
Choose BM680 If:
- Production volume is your highest priority.
- You regularly mix large batches.
- You operate on commercial construction sites.
Choose BM679C If:
- Budget is important.
- You are comfortable with a traditional cycloidal gearbox that requires periodic grease replacement.
- You mainly mix mortar, render, or standard cement products.
Daily Maintenance Guide for Forced Action Mixers
Cleaning and general inspection are important for all models, but gearbox maintenance differs by model: BM678 and BM680 use maintenance-free R-type reducer gearboxes, while BM679C requires periodic gearbox grease replacement.
After Every Use
Clean Immediately
Never allow mortar or concrete to harden inside the drum.
Recommended procedure:
- Empty the mixer completely.
- Add water and a small amount of aggregate.
- Run the mixer for several minutes.
- Wash all internal surfaces thoroughly.
- Remove remaining residue manually if required.
Failure to clean promptly can lead to:
- Reduced mixing efficiency
- Blade damage
- Excessive motor load
Inspect Mixing Blades
Check for:
- Excessive wear
- Bent blades
- Loose fasteners
Worn blades reduce mixing efficiency and increase cycle times.
Weekly Maintenance
Check Fasteners
Inspect:
- Blade bolts
- Frame bolts
- Wheel hardware
- Hopper guard fixings
Vibration can gradually loosen fasteners during operation.
Inspect Electrical Components
Check:
- Power cable condition
- Plug connections
- Safety switch operation
- Emergency stop functions
Replace damaged electrical components immediately.
Monthly Maintenance
Inspect Gearbox and Drive System
Check for:
- Oil leaks
- Abnormal noise
- Excessive vibration
- Overheating
Any unusual gearbox noise should be investigated before continued operation. BM678 and BM680 do not require routine gearbox grease replacement. For BM679C, check the gearbox grease condition periodically and replace it with lithium-based grease as required.
Check Bearings
Inspect shaft bearings for:
- Play
- Noise
- Heat generation
Early detection prevents costly failures.
Long-Term Storage
When storing the mixer for extended periods:
- Thoroughly clean the machine.
- Dry all components completely.
- Protect exposed metal surfaces with light oil.
- Store indoors.
- Cover electrical components from moisture.
Proper storage prevents corrosion and extends machine lifespan.
Final Verdict
All three Forestwest mixers are capable commercial-grade machines, but they serve different users.
The BM678 is the most balanced choice for contractors seeking reliability and minimal maintenance.
The BM680 is the productivity leader, offering the highest batch output and best efficiency for commercial operations.
The BM679C remains an excellent heavy-duty mixer with a robust traditional cycloidal drive system and powerful four-blade mixing action, making it a strong value option for professional users who are comfortable with periodic gearbox grease replacement using lithium-based grease.
For most contractors, the BM678 provides the best combination of performance, portability, maintenance-free R-type gearbox design, and long-term ownership value. The BM680 becomes the preferred choice when daily production volume is the primary consideration, while still offering the same higher-grade maintenance-free gearbox advantage.