CRL Gunther Extra/Build® Mirror Mastic Cartridge - Mirror Adhesive

• Available in two high-strength formulas
• Builds out to 2-1/2" (64 mm) without sag
• Ideal for large mirrored walls, vanities, and uneven surfaces
• Available in 10.1 Fl. Oz. cartridges or gallon cans

CRL Gunther Ultra/Bond® and Extra/Build® Mirror Mastics are premium mirror adhesives formulated to provide a strong, permanent bond between electro-copper-plated glass mirror and common substrates. Field tested for compatibility with silver, copper and mirror backing, these mirror mastics offer year‑round working consistency and adhere to drywall, wood, metal, glass, marble and tile. SKU: GN200A.

Gunther Extra/Build® has a high-viscosity formula that allows build-out up to 2-1/2" (64 mm) without sag—ideal for custom mirrored walls or installations with gaps greater than 3/4" (19 mm).

Approximate Cure Profile for Gunther Extra/Build®
Approximate percent of maximum strength:
@ 24 hours — 25%
@ 3 days — 50%
@ 7 days — 75%
@ 30 days — 100%

• Curing time depends on temperature and air exposure; smaller spots cure faster than larger ones.
• Mounting time: mirrors can be mounted up to 20 minutes after application.
• Adjusting time: adhesive can be adjusted for up to 24 hours after installation to ensure proper alignment.

Application Notes:
For best results, apply Gunther Extra/Build® in 4" diameter patties for every square foot. Not for exterior use. Test for bleeding on porous or treated substrates prior to full installation.

Limitations

• Not for outdoor use.
• Do not use on acrylic mirrors.
• Do not apply directly to wallpaper, safety films made of vinyl, or treated wood.
• For full instructions and technical details, consult the product data sheets.

Product Warning:
Keep away from heat, sparks and open flame. Vapors may ignite; avoid smoking and eliminate ignition sources. Use only with adequate ventilation—vapors can cause dizziness, headaches or nausea and repeated/prolonged inhalation can affect the central nervous system, liver or kidneys. Avoid skin, eye and clothing contact. ABUSE OR INTENTIONAL INHALATION MAY RESULT IN SERIOUS INJURY.

CRL, Gunther Mirror Mastics, the manufacturer or Royal Adhesives and Sealants LLC shall not be liable for consequential damages arising from product use. Liability is limited to the purchase price of the goods. Users are responsible for determining suitability for specific mirror backing