1384 Bungalow Rd.
Morris, Illinois, U.S.A.
Prep/Master Sr. – 27″ Electric Concrete Floor Grinder
4409 https://substratetechnology.com/wp-content/uploads/2021/06/Pm-Sr-Full-View-5-e1781127104910-830x1024.png
Weight: 923.00lb
Dimensions: 46.00in x 27.00in x 46.00in
Attachments: STI-Sales-Sheet_PMSr.pdf
Heavy-Duty Production Without the Bulk
The Prep/Master® Sr. gives you the production capacity of a heavy-duty concrete floor grinder in a maneuverable, transportable package. Built for professional surface preparation and polishing, it features a 27-inch grinding width and a powerful 20HP motor for consistent performance on commercial and production flooring projects.
The moveable pocket weight system adjusts head pressure to the job, and the standard water tank makes it easy to switch from dry to wet work. Recommended for project sizes up to 5,000 SF (500m²).
Ready to put the PM Sr. to work? Call for pricing and availability, or request a quote — and you’ll talk to a real surface-prep expert, not a call center.
Speak directly with a surface preparation expert — fast answers and real recommendations.
New to grinders? Read our guide on choosing the right one!
Improved and Tested Before It Ships
The Prep/Master Sr. isn’t a cheap import pulled off a shelf. Before it reaches you, we improve it:
- Upgraded couplers — we replace the cheap originals with better, more durable ones built for real work
- Better tool plates — for more reliable tooling attachment and performance
- An improved electrical drive — for more dependable, consistent operation
- Every component tested — we test every component and run the machine before it ships, so it arrives ready to work
And we back it with genuine parts, real service, and surface-prep experts a phone call away — support a cheap import can’t match. Weighing the Sr. against a cheaper import? See what you’re really paying for →
Key Features
- 27″ Grinding Width — efficient coverage for faster production
- 20HP Electric Motor — high torque for demanding, high-production applications
- Variable Speed Drive — adjust for grinding or polishing conditions
- 4 Tool Plates / 12 Tools with EG Quick-Change Plates — consistent multi-head grinding
- Adjustable Weight System — customize head pressure to the application
- Wet or Dry Operation — built-in water tank for versatility
Special Features
- Two 44 lb attached weights
- Heavy head pressure for a better grind and polish — 60% of its weight is on the head
- LED Light to illuminate the cutting path
- Compact, foldable frame that separates into two pieces for easy transport and storage
- Carrying poles for two-to-three-person lifting
- 10-gallon (37 L) water tank
- On-board USB charger & phone carrier
Specifications
- Working Width: 27″ (68 cm)
- Motor: WEG 20 HP (14 kW), 1 or 3 phase
- Voltage: 230V
- Weight: approx. 923 lbs (420 kg)
- Dimensions: 46″ L × 27″ W × 46″ H
- Tool Plates: 4 · Total Tooling: 12 tools
- Recommended Project Size: up to 5,000 sq ft
Applications
- Concrete grinding and polishing
- Epoxy, coating, adhesive, and mastic removal
- Warehouse and commercial floor prep
- Terrazzo, stone, and marble finishing (with proper tooling)
- Commercial and production flooring projects
Sr. or Jr. — Which Prep/Master Is Right for You?
- Prep/Master Sr. (this machine) — 27″, for larger commercial and production jobs up to 5,000 sq ft; warehouses, bigger floors
- Prep/Master Jr. — 23″, for residential and small jobs up to 1,000 sq ft; garages, basements, tight areas
Not sure which fits your work? Call us and we’ll help you choose.
Financing Available
For a production machine like the Sr., financing lets you put it to work now and spread the investment into manageable monthly payments — keeping your cash flow flexible. Ask about our financing options →
Warranty & Support
Every Prep/Master Sr. is backed by our Prep/Master® warranty and our in-house service and parts — so you’re supported long after the sale.
Frequently Asked Questions
What size jobs is the PM Sr. best for? Projects up to 5,000 square feet — ideal for commercial, warehouse, and production flooring.
Can it polish concrete? Yes — with proper tooling, it handles both grinding and polishing.
What power does it require? 230V, available in 1 or 3 phase.
What surfaces can it handle? Concrete, terrazzo, marble, and stone.
How is it different from the Jr.? The Sr. is larger (27″ vs. 23″) and more powerful (20HP vs. 7.5HP), built for bigger commercial and production jobs up to 5,000 sq ft.
What makes it different from a cheap import? We upgrade the couplers, tool plates, and electrical drive, test every component before shipping, and back it with genuine parts and real support.
Compact design and foldable
frame, that can be also separated
in two pieces for easy
transportation and storage
Uses 12 Tools and EG Quick Change Tool Plates!
Order Your Prep/Master Sr. Today
Call (815) 941-4800 x 1 or fill out our contact form. New to grinders? Read our guide on choosing the right one. See our diamond tooling and dust collectors.
Item #718000220
Surface Preparation
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