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Substrate Technology, Inc.

Prep/Master Jr.

Prep/Master Jr. The Prep/Master Jr. (formerly known as the Eco/Prep II) grinder from STI is ideal for polishing projects over 1,000 SF (93 m2). The new and improved design gives increased performance. Heavier head pressure allows a better grind and polish than the old Eco/Prep 500. Features include: an 8-gallon (30 liters) water tank; magnetic LED Light to illuminate front of machine or behind machine on the cutting path; screw-in carrying poles for easy two to three person lifting; and an on-board USB charger & phone carrier. The Prep/Master Jr. is easy to disassemble into two sections for quick transportation in the back of an SUV or pickup.

Features and Benefits

Specifications: Motor 7.5 HP, Variable Speed Drive (5.6kW) Power Source 220-240V Single Phase, 40A RPM 250-500 RPM Variable Tools Needed 6 Tools Attachment Style EG Proprietary Attachment System Vacuum Hose Connection 2” (50 mm) — sold separately Recommended Vacuum 3003G (300CFM) or equivalent Production Rates: Mastic Removal 200SF / 19 M2 per hour Thin Set Removal 200 SF / 19 M2 per hour Mil Coatings Removal 50SF / 5 M2 per hour Concrete Polishing 300SF / 28 M2 per hour STI Diamond Systems that can be used on the Eco/Prep II: Polished Concrete: EGT Polishing System (dry) & CLC Polishing System (wet-dry) Polished Terrazzo: TPS Polishing System


50” L x 23” W x 48” H (127cm x 58cm x 122cm)

Working Width 23in. (58 cm)


7.5 HP, Variable Speed Drive (5.6kW) / 7.5 HP



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