Please login with your username and password.


Can’t remember your accounts password?

Can't access your account?

Select your language.

This page is available in the following languages:

    Please select your location

    MasterFlow 640

    Grout accelerator for MasterFlow 648

    Formerly: MasterFlow 648 CP Grout Accelerator

    How does MasterFlow 640 work?

    When MasterFlow 640 is added to MasterFlow 648, it accelerates the cure rate at low temperatures. MasterFlow 640 should be used in temperatures below 60º F (16º C).

    Recommended uses:

    • Where heating exterior spaces is impractical
    • Where temperatures fall below 60º F (16º C)
    • Where high early strengths are required

    What are the unique features of MasterFlow 640?

    • Accelerated cure rate
    • Early strength development

    What are the benefits of MasterFlow 640?

    • Enables cold-weather applications
    • Early return to service​

    Direct contact

    Master Builders Solutions Technical Support

    Construction Systems


    Safety Data Sheet (SDS)

    Find all available safety data sheets for this product.

    Product Certifications

    Generate a free certificate of conformance for a specific Master Builders Solutions construction product.

    LEED v4 & v4.1 Teaser Image

    LEED v4 & v4.1

    Search by product or CSI code and download up to date LEED information.

    Related Literature

    Certification Letter

    pdf (89.67 Kb)

    Data Guide

    pdf (190.92 Kb)

    MasterFlow 640

    pdf (490.55 Kb)

    MasterFlow 640

    pdf (377.56 Kb)

    MasterFlow 640

    pdf (360.51 Kb)

    MasterFlow 640

    pdf (476.23 Kb)

    MasterFlow 640 Data Guide (French)

    pdf (281.21 Kb)