H.B. Fuller Ultra/Bond® Mirror Mastic

H.B. Fuller Ultra/Bond® Mirror Mastic is a proven formula for professional mirror installations. Gunther Ultra/Bond® is blended to achieve maximum adhesion, providing a permanent bond between the mirror and a variety of substrates. Ultra/Bond® can compress to 1/32", making it ideal for mirror installations requiring close tolerances, such as overlays and mirrored furniture. For those uneven surfaces, Ultra/Bond® will build up to 3/4". Bonds metal, glass, mirror, wood and stone.

Product Type: Adhesive

Application Area: Mirror

Compatible Substrates & Surfaces: Glass, Metal, Stone, Wood

Application Method: Gun

Technical Data Sheet
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Identification & Functionality

Features & Benefits

Ready-to-Use Product Features
Key Attributes
  • Strong - Over 600 lbs per square inch Tested strength, totally cured after 28 days. In most cases Gunther Ultra/Bond® is much stronger than the surfaces to which it is applied.
  • Quality Proven - Many years of extensive laboratory testing and field use has given Gunther Ultra/Bond® a record of quality mirror Installations.
  • Easy Working Consistency Year-round - At operating temperatures ranging from 10°F to 125°F, Gunther Ultra/Bond® remains easy to apply. For best adhesion the two surfaces must be dry, clean and above 60°F.
  • Versatile - Ultra/Bond® can compress to 1/32”, making it ideal for mirror installations requiring close tolerances such as overlays and mirrored furniture. For those uneven surfaces, Ultra/Bond® will build up to 3/4”. Bonds metal, glass, mirror, wood and stone.
  • Convenient Drying - Gunther Ultra/Bond® cures to 30% of maximum strength in 24 hours. Cures to 100% strength in 28 days at normal room temperatures.

Applications & Uses

Application Area
Application Method
Compatible Substrates & Surfaces
Application Instructions

Installation Instructions

  1. The surface must be clean, dry and free from dust, dirt, greasy film, loose or powdery paint or primer. For assurance sand to the base surface. Clean and seal with Gunther Prime-N-Seal™, let fully dry. When applying mirror to vertical unpainted plaster, wallboard, wood, particle board, hardboard and concrete, the surface to be covered must be sealed with Gunther Prime-N-Seal™. Do not apply on wallpaper, painted surfaces, vinyl safety backing, acrylic mirror, or treated woods. Not for external applications. Sealant, wall and mirror surfaces must be above 60°F. For additional information and Installation procedure, refer to Specification Data Sheet.
  2. Gunther Ultra/Bond® should be applied in vertical beads the full length of the mirror, 5-6” apart. Allow 3” from the mirror edge to begin or end a bead. Install the mirror within 10 minutes after Ultra/Bond® has been applied.
  3. Use a mechanical support system to support mirror during and after installation.
  4. Gunther Ultra/Bond® will create a skin in twenty seconds after application that will feel dry to the touch. This will prevent dust or dirt from adhering to the Ultra/Bond® surface. When the mirror is set in place on the wall, the surface skin will dissolve for maximum contact with both the mirror backing and the wall. Once the mirror has been placed on the wall do not remove for the purpose of “air tacking”. Maximum strength is obtained by letting Gunther Ultra/Bond® cure to both surfaces without breaking the bond. MIRROR OVERLAYS: Working with mirror strips can be difficult. For overlays, use Gunther Ultra/Bond® or Premier® Plus to achieve a fast set and strength along with double-faced tape. Ultra/Bond® has the capability to compress to 1/32”, Premier® Plus to 1/16”, providing a professional installation. Double-faced tape is used only for initial adhesion to support the mirror. The mastic is for long term adhesion and strength. Mastic beads of 1/4” to 3/8” thick by 6” long, leaving a 3” gap between where the bead starts will improve curing time. NOTE: Check with mirror manufacturer on recommended double-faced tape.
  5. Acutal curing time for Ultra/Bond® may vary depending on conditions.


For easy cleanup use mineral spirits. Test the material to be cleaned to make sure mineral spirits will not cause any damage.

Safety & Health


FLAMMABLE vapors from Extra/Build® may ignite explosively; prevent build-up of vapors. Open all windows and doors. Use only with cross ventilation. Do not smoke. Extinguish all flames and pilot lights and turn off stoves, heaters, electric motors and other sources of ignition during use and until all vapors are gone. Close container after use. Keep away from heat, sparks and open flame.

Packaging & Availability

Packaging Type
  • 20 fl oz sausage
  • 300 ml cartridge
  • 1 gallon can
  • 5 gallon pail

Storage & Handling

Shelf Life
1 Year
Storage Conditions

Shelf life is one year in original unopened containers when stored between 40°F - 80°F.